[Federal Register Volume 61, Number 77 (Friday, April 19, 1996)]
[Proposed Rules]
[Pages 17358-17536]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 96-7872]




[[Page 17357]]


_______________________________________________________________________

Part II





Environmental Protection Agency





_______________________________________________________________________



40 CFR Part 60, et al.



Hazardous Waste Combustors; Revised Standards; Proposed Rule

Federal Register / Vol. 61, No. 77 / Friday, April 19, 1996 / 
Proposed Rules

[[Page 17358]]



ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60, 63, 260, 261, 264, 265, 266, 270, and 271

[FRL-5447-2]
RIN 2050-AF01


Revised Standards for Hazardous Waste Combustors

agency: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: The Agency is proposing revised standards for hazardous waste 
incinerators, hazardous waste-burning cement kilns, and hazardous 
waste-burning lightweight aggregate kilns. These standards are being 
proposed under joint authority of the Clean Air Act (CAA) and Resource 
Conservation and Recovery Act (RCRA). The standards limit emissions of 
chlorinated dioxins and furans, other toxic organic compounds, toxic 
metals, hydrochloric acid, chlorine gas, and particulate matter. These 
standards reflect the performance of Maximum Achievable Control 
Technologies (MACT) as specified by the Clean Air Act. The MACT 
standards also should result in increased protection to human health 
and the environment over existing RCRA standards. The nature of this 
proposal requires that the following actions also be proposed: 
proposing the addition of hazardous waste-burning lightweight aggregate 
kilns to the list of source categories in accordance with 112(c)(5) of 
the Act; exempting from RCRA emission controls secondary lead 
facilities subject to MACT; considering an exclusion for certain 
``comparable fuels''; and revising the small quantity burner exemption 
under the BIF rule.

DATES: EPA will accept public comments on this proposed rule until June 
18, 1996.

ADDRESSES: Commenters must send an original and two copies of their 
comments referencing docket number F-96-RCSP-FFFFF to: RCRA Docket 
Information Center, Office of Solid Waste (5305W), U.S. Environmental 
Protection Agency Headquarters (EPA, HQ), 401 M Street, SW., 
Washington, DC 20460. Deliveries of comments should be made to the 
Arlington, VA, address listed below. Comments may also be submitted 
electronically through the Internet to: RCRA-Docket@epamail.epa.gov. 
Comments in electronic format should also be identified by the docket 
number F-96-RCSP-FFFFF. All electronic comments must be submitted as an 
ASCII file avoiding the use of special characters and any form of 
encryption.
    Commenters should not submit electronically any Confidential 
Business Information (CBI). An original and two copies of CBI must be 
submitted under separate cover to: RCRA CBI Document Control Officer, 
Office of Solid Waste (5305W), U.S. EPA, 401 M Street, SW, Washington, 
DC 20460.
    Public comments and supporting materials are available for viewing 
in the RCRA Information Center (RIC), located at Crystal Gateway One, 
1235 Jefferson Davis Highway, First Floor, Arlington, VA. The RIC is 
open from 9 a.m. to 4 p.m., Monday through Friday, excluding federal 
holidays. To review docket materials, the public must make an 
appointment by calling (703) 603-9230. The public may copy a maximum of 
100 pages from any regulatory docket at no charge. Additional copies 
cost $.15/page. The index and some supporting materials are available 
electronically. See the ``Supplementary Information'' section for 
information on accessing them.
    A public hearing will be held, if requested, to discuss the 
proposed standards for hazardous waste combustors, in accordance with 
section 307(d)(5) of the Act. Persons wishing to make an oral 
presentation at a public hearing should contact the EPA at the address 
given in the ADDRESSES section of this preamble. Oral presentations 
will be limited to 5 minutes each, unless additional time is feasible. 
Any member of the public may file a written statement before, during, 
or within 30 days after the hearing. Written statements should be 
addressed to the RCRA Docket Section address given in the ADDRESSES 
section of this preamble and should refer to Docket No. F-96-RCSP-
FFFFF. A verbatim transcript of the hearing and written statements will 
be available for public inspection and copying during normal working 
hours at the EPA's RCRA Docket Section in Washington, D.C. (see 
ADDRESSES section of this preamble).

FOR FURTHER INFORMATION CONTACT: For general information, contact the 
RCRA Hotline at 1-800-424-9346 or TDD 1-800-553-7672 (hearing 
impaired). In the Washington metropolitan area, call 703-412-9810 or 
TDD 703-412-3323.
    For more detailed information on specific aspects of this 
rulemaking, contact Larry Denyer, Office of Solid Waste (5302W), U.S. 
Environmental Protection Agency, 401 M Street, SW., Washington, DC 
20460, (703) 308-8770, electronic mail: Denyer.Larry@epamail.epa.gov. 
For more detailed information on implementation of this rulemaking, 
contact Val de la Fuente, Office of Solid Waste (5303W), U.S. 
Environmental Protection Agency, 401 M Street, SW., Washington, DC 
20460, (703) 308-7245, electronic mail: DeLaFuente.Val@epamail.epa.gov. 
For more detailed information on regulatory impact assessment of this 
rulemaking, contact Gary Ballard, Office of Solid Waste (5305), U.S. 
Environmental Protection Agency, 401 M Street, SW., Washington, DC 
20460, (202) 260-2429, electronic mail: Ballard.Gary@epamail.epa.gov. 
For more detailed information on risk analyses of this rulemaking, 
contact David Layland, Office of Solid Waste (5304), U.S. Environmental 
Protection Agency, 401 M Street, SW., Washington, DC 20460, (202) 260-
4796, electronic mail: Layland.David@epamail.epa.gov.

SUPPLEMENTARY INFORMATION: The index and the following supporting 
materials are available on the Internet: (List documents) Follow these 
instructions to access the information electronically:
Gopher: gopher.epa.gov
WWW: http://www.epa.gov
Dial-up: (919) 558-0335.
    This report can be accessed off the main EPA Gopher menu, in the 
directory: EPA Offices and Regions/Office of Solid Waste and Emergency 
Response (OSWER)/Office of Solid Waste (RCRA)/(consult with 
Communication Strategist for precise subject heading)
FTP: ftp.epa.gov
Login: anonymous
Password: Your Internet address
    Files are located in /pub/gopher/OSWRCRA
    The official record for this action will be kept in paper form. 
Accordingly, EPA will transfer all comments received electronically 
into paper form and place them in the official record, which will also 
include all comments submitted directly in writing. The official record 
is the paper record maintained at the address in ADDRESSES at the 
beginning of this document.
    EPA responses to comments, whether the comments are written or 
electronic, will be in a notice in the Federal Register or in a 
response to comments document placed in the official record for this 
rulemaking. EPA will not immediately reply to commenters electronically 
other than to seek clarification of electronic comments that may be 
garbled in transmission or during conversion to paper form, as 
discussed above.

Glossary of Acronyms

APCD--Air Pollution Control Device

[[Page 17359]]

BDAT--Best Demonstrated Available Technology
BIFs--Boilers and Industrial Furnaces
BTF--Beyond-the-Floor
CAA--Clean Air Act
Cl2--Chlorine
CO--Carbon Monoxide
D/F--Dioxins/Furans
D/O/M--Design/Operation/Maintenance
ESP--Electrostatic Precipitator
EU--European Union
FF--Fabric Filter
HAP--Hazardous Air Pollutant
HC--Hydrocarbons
HCl--Hydrochloric acid
Hg--Mercury
HHE--Human Health and the Environment
HON--Hazardous Organic NESHAPs
HSWA--Hazardous and Solid Waste Amendments
HWC--Hazardous Waste Combustion/Combustor
ICR--Information Collection Request
LDR--Land Disposal Restrictions
LVM--Low-volatile Metals
LWAK--Lightweight Aggregate Kiln
MACT--Maximum Achievable Control Technology
MTEC--Maximum Theoretical Emission Concentration
NESHAPs--National Emission Standards for Hazardous Air Pollutants
PM--Particulate Matter
PICs--Products of Incomplete Combustion
RCRA--Resource Conservation and Recovery Act
RIA--Regulatory Impact Assessment
SVM--Semivolatile Metals
TCLP--Toxicity Characteristic Leaching Procedure
UTS--Universal Treatment Standards

Part One: Background
    I. Overview
    II. Relationship of Today's Proposal to EPA's Waste Minimization 
National Plan
Part Two: Devices That Would Be Subject To The Proposed Emission 
Standards
    I. Hazardous Waste Incinerators
    A. Overview
    B. Summary of Major Incinerator Designs
     C. Number of Incinerator Facilities
     D. Typical Emission Control Devices For Incinerators
    II. Hazardous Waste-Burning Cement Kilns
    A. Overview of Cement Manufacturing
    B. Summary of Major Design and Operating Features of Cement 
Kilns
    C. Number of Facilities
    D. Emissions Control Devices
    III. Hazardous Waste-Burning Lightweight Aggregate Kilns
    A. Overview of Lightweight Aggregate Kilns (LWAKs)
    B. Major Design and Operating Features
    C. Number of Facilities
    D. Air Pollution Control Devices
Part Three: Decision Process for Setting National Emission Standards 
for Hazardous Air Pollutants (NESHAPs)
    I. Source of Authority for NESHAP Development
    II. Procedures and Criteria for Development of NESHAPs
    III. List of Categories of Major and Area Sources
    A. Clean Air Act Requirements
    B. Hazardous Waste Incinerators
    C. Cement Kilns
    D. Lightweight Aggregate Kilns
    IV. Proposal to Subject Area Sources to the NESHAPs under 
Authority of Section 112(c)(6)
    V. Selection of MACT Floor for Existing Sources
    A. Proposed Approach: Combined Technology-Statistical Approach
    B. Another Approach Considered But Not Used
    C. Identifying Floors as Proposed in CETRED
    D. Establishing Floors One HAP or HAP Group at a Time
    VI. Selection of Beyond-the-Floor Levels for Existing Sources
    VII. Selection of MACT for New Sources
    VIII. RCRA Decision Process
    A. RCRA and CAA Mandates to Protect Human Health and the 
Environment
    B. Evaluation of Protectiveness
     C. Use of Site-Specific Risk Assessments under RCRA
Part Four: Rationale for Selecting the Proposed Standards
    I. Selection of Source Categories and Pollutants
    A. Selection of Sources and Source Categories
    B. Selection of Pollutants
    C. Applicability of the Standards Under Special Circumstances
    II. Selection of Format for the Proposed Standards
    A. Format of the Standard
    B. Averaging Periods
    III. Incinerators: Basis and Level for the Proposed NESHAP 
Standards for New and Existing Sources
    A. Summary of MACT Standards for Existing Incinerators
    B. Summary of MACT Standards For New Incinerators
    C. Evaluation of Protectiveness
    IV. Cement Kilns: Basis and Level for the Proposed NESHAP 
Standards for New and Existing Sources
    A. Summary of Standards for Existing Cement Kilns
    B. MACT for New Hazardous Waste-Burning Cement Kilns
    C. Evaluation of Protectiveness
    V. Lightweight Aggregate Kilns: Basis and Level for the Proposed 
NESHAP Standards for New and Existing Sources
    A. Summary of MACT Standards for Existing LWAKs
    B. MACT for New Sources
    C. Evaluation of Protectiveness
    VI. Achievability of the Floor Levels
    VII. Comparison of the Proposed Emission Standards With Emission 
Standards for Other Combustion Devices
    VIII. Alternative Floor (12 Percent) Option Results
    A. Summary of Results of 12 Percent Analysis
    B. Summary of MACT Floor Cost Impacts and Emissions Reductions
    C. Alternative Floor Option: Percent Reduction Refinement
    IX. Additional Data for Comment
Part Five: Implementation
    I. Selection of Compliance Dates
    A. Existing Sources
    B. New Sources
    C. One year extensions for Pollution Prevention/Waste 
Minimization
    II. Selection of Proposed Monitoring Requirements
    A. Monitoring Hierarchy
    B. Use of Comprehensive Performance Test Data to Establish 
Operating Limits
    C. Compliance Monitoring Requirements
    D. Combustion Fugitive Emissions
    E. Automatic Waste Feed Cutoff (AWFCO) Requirements and 
Emergency Safety Vent (ESV) Openings
    F. Quality Assurance for Continuous Monitoring Systems
    III. MACT Performance Testing and Related Issues
    A. MACT Performance Testing
    B. RCRA Trial Burns
    C. Waiver of MACT Performance Testing for HWCs Feeding De 
Minimis Levels of Metals or Chlorine
    D. Relative Accuracy Tests for CEMS
    IV. Selection of Manual Stack Sampling Methods
    V. Notification, Recordkeeping, Reporting, and Operator 
Certification Requirements
    A. Notification Requirements
    B. Reporting Requirements
    C. Recordkeeping Requirements
    VI. Permit Requirements
    A. Coordination of RCRA and CAA Permitting Processes
    B. Permit Application Requirements
    C. Clarifications on Definitions and Permit Process Issues
    D. Pollution Prevention/Waste Minimization Options
    E. Permit Modifications Necessary to Come Into Compliance With 
MACT Standards
    VII. State Authorization
    A. Authority for Today's Rule
    B. Program Delegation Under the Clean Air Act
    C. RCRA State Authorization
    VIII. Definitions
    A. Definitions Proposed in Sec. 63.1201
    B. Conforming Definitions Proposed in Secs. 260.10 and 270.2
    C. Clarification of RCRA Definition of Industrial Furnace
Part Six: Miscellaneous Provisions and Issues
    I. Comparable Fuel Exclusion
    A. EPA's Approach to Establishing Benchmark Constituent Levels
    B. Sampling, Analysis, and Statistical Protocols Used
    C. Options for the Benchmark Approach
    D. Comparable Fuel Specification
    E. Exclusion of Synthesis Gas Fuel
    F. Implementation of the Exclusion
    G. Transportation and Storage
    H. Speculative Accumulation
    I. Regulatory Impacts
    II. Miscellaneous Revisions to the Existing Rules
    A. Revisions to the Small Quantity Burner Exemption under the 
BIF Rule
    B. The Waiver of the PM Standard under the Low Risk Waste 
Exemption of the

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BIF Rule Would Not Be Applicable to HWCs
    C. The ``Low Risk Waste'' Exemption from the Emission Standards 
Provided by the Existing Incinerator Standards Would Be Superseded 
by the MACT Rules
    D. Bevill Residues
    E. Applicability of Regulations to Cyanide Wastes
    F. Shakedown Concerns
    G. Extensions of Time Under Certification of Compliance
    H. Technical Amendments to the BIF Rule
    I. Clarification of Regulatory Status of Fuel Blenders
    J. Change in Reporting Requirements for Secondary Lead Smelters 
Subject to MACT
Part Seven: Analytical and Regulatory Requirements
    I. Executive Order 12866
    II. Regulatory Options
    III. Assessment of Potential Costs and Benefits
    A. Introduction
    B. Analysis and Findings
    C. Total Incremental Cost per Incremental Reduction in HAP 
Emissions
    D. Human Health Benefits
    E. Other Benefits
    IV. Other Regulatory Issues
    A. Environmental Justice
    B. Unfunded Federal Mandates
    C. Regulatory Takings
    D. Incentives for Waste Minimization and Pollution Prevention
    V. Regulatory Flexibility Analysis
    VI. Paperwork Reduction Act
    VII. Request for Data
Appendix--Comparable Fuel Constituent and Physical Specifications
PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES
PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS 
FOR SOURCE CATEGORIES
PART 260--HAZARDOUS WASTE MANAGEMENT SYSTEM: GENERAL
PART 261--IDENTIFICATION AND LISTING OF HAZARDOUS WASTE
PART 264--STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE 
TREATMENT, STORAGE, AND DISPOSAL FACILITIES
PART 265--INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF 
HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES
PART 266--STANDARDS FOR THE MANAGEMENT OF SPECIFIC HAZARDOUS WASTES 
AND SPECIFIC TYPES OF HAZARDOUS WASTE MANAGEMENT FACILITIES
PART 270--EPA ADMINISTERED PERMIT PROGRAMS: THE HAZARDOUS WASTE 
PERMIT PROGRAM
PART 271--REQUIREMENTS FOR AUTHORIZATION OF STATE HAZARDOUS WASTE 
PROGRAMS

PART ONE: BACKGROUND

I. Overview

    The U.S. Environmental Protection Agency (EPA) is proposing to 
revise standards for hazardous waste incinerators and hazardous waste-
burning cement kilns and lightweight aggregate kilns (LWAKs) under 
joint authority of the Clean Air Act, as amended, (CAA) and the 
Resource Conservation and Recovery Act, as amended (RCRA). The emission 
standards in today's proposal have been developed under the CAA 
provisions concerning the maximum level of achievable control over 
hazardous air pollutants (HAPs), taking into consideration the cost of 
achieving the emission reduction, any non-air quality health and 
environmental impacts, and energy requirements. These maximum 
achievable control technology (MACT) standards, also referred to as 
National Emission Standards for Hazardous Air Pollutants (NESHAPs), are 
proposed in today's rule for the following HAPs: dioxins/furans, 
mercury, two semivolatile metals (lead and cadmium), four low 
volatility metals (antimony, arsenic, beryllium, and chromium), 
particulate matter, and hydrochloric acid/chlorine gas. Other toxic 
organic emissions are addressed by standards for carbon monoxide (CO) 
and hydrocarbons (HC).
    This action is being taken for several reasons. First, this 
proposal is consistent with the terms of the 1993 settlement agreement 
between the Agency and a number of groups who challenged EPA's final 
RCRA rule entitled ``Burning of Hazardous Waste in Boilers and 
Industrial Furnaces'' (56 FR 7134, Feb. 21, 1991). These groups include 
the Natural Resources Defense Council, Sierra Club, Inc., Hazardous 
Waste Treatment Council (now the Environmental Technology Council), 
National Solid Waste Management Association, and a number of local 
citizens' groups. Under this settlement agreement, the Agency is to 
propose this rulemaking by September-November, 1995, and finalize it by 
December 1996.
    Second, EPA has scheduled rulemakings to develop maximum achievable 
control technology (MACT) standards for hazardous waste incinerators 
and cement kilns. To minimize the burden on the Agency and the 
regulated community, the Agency has combined its efforts under the CAA 
and RCRA into one rulemaking to establish MACT standards, which also 
would satisfy the RCRA settlement agreement obligations.
    Third, the Agency's Hazardous Waste Minimization and Combustion 
Strategy, first announced in May 1993, in addition to stressing waste 
minimization, also made a commitment to upgrade the emission standards 
for hazardous waste-burning facilities. The three categories of 
facilities covered in this proposal burn over 80 percent of the total 
amount of hazardous waste being combusted each year. [The remaining 15-
20 percent is burned in industrial boilers and other types of 
industrial furnaces, which are to be addressed in the next rulemaking 
for which a proposal is to be issued by December 1998 or sooner.]
    Finally, as relates to the development of revised standards under 
concurrent Clean Air Act and RCRA authority, most of these hazardous 
waste combustion facilities are major sources of HAP emissions. They 
therefore must be regulated under section 112(d) of the Clean Air Act. 
In addition, EPA noted, when promulgating the RCRA rules for boilers 
and industrial furnaces in 1991 and in a proposal to revise the 
incinerator rules, that existing standards did not fully consider the 
possibility of exposure via indirect (non-inhalation) exposure 
pathways. 56 FR at 7150, 7167, 7169-70 (Feb. 21, 1991); 54 FR at 43720-
21, 43723, 43757 (Oct. 26, 1989). The Agency reiterated these concerns 
in the Combustion Strategy announced in 1993 as one of the major 
factors leading to its decision to undertake revisions to the standards 
for hazardous waste combustors. As also noted in the Combustion 
Strategy and elsewhere, site-specific RCRA omnibus authority, whereby 
permit writers can impose additional conditions as are necessary to 
protect human health and the environment, can be used to buttress the 
existing regulations. See, e.g., 56 FR 7145, at n.8. Nevertheless, this 
process is expensive, time-consuming, and not always sufficiently 
certain in result. The Agency thus indicated, in the Combustion 
Strategy, that technology-based standards could provide a superior 
means of control by providing certainty of operating performance.
    Because of the joint authorities under which this rule is being 
proposed, the proposal also contains an implementation scheme that is 
intended to harmonize the RCRA and CAA programs to the maximum extent 
permissible by law. In pursuing a common-sense approach towards this 
objective, the proposal seeks to establish a framework that: (1) 
Provides for combined (or at least coordinated) CAA and RCRA permitting 
of these facilities; (2) allows maximum flexibility for regional, 
state, and local agencies to determine which of their resources will be 
used for permitting, compliance, and enforcement efforts; and (3) 
integrates the monitoring, compliance testing, and recordkeeping 
requirements of the CAA and RCRA so that facilities will be able

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to avoid two potentially different regulatory compliance schemes.
    In addition, this proposal addresses the variety of issues, to the 
extent appropriate at this time, raised in several petitions filed with 
the Agency. These petitions are from the Cement Kiln Recycling 
Coalition (Jan. 18, 1994), the Hazardous Waste Treatment Council (May 
18, 1994), and the Chemical Manufacturers Association (Oct. 14, 1994).

II. Relationship of Today's Proposal to EPA's Waste Minimization 
National Plan

    EPA believes that today's proposed rule will create significant 
incentives for source reduction and recycling by waste generators that 
would, in turn, help facilities achieve compliance with the MACT 
standards. RCRA, as well as the Pollution Prevention Act of 1990 (PPA), 
encourage pollution prevention at the source, and the Clean Air Act 
mentions pollution prevention as a specific means of achieving MACT. In 
Sec. 112(d)(2) of the CAA, Congress expressly defined MACT as the 
``application of measures, processes, methods, systems, or techniques 
including, but not limited to, measures which reduce the volume of, or 
eliminate emissions of, such pollutants through process changes, 
substitution of materials and other modifications.''
    In addition, in the Hazardous and Solid Waste Amendments of 1984 
(HSWA) to RCRA, Congress established a national policy for waste 
minimization. Section 1003 of RCRA states that, whenever feasible, the 
generation of hazardous waste is to be reduced or eliminated as 
expeditiously as possible. Section 8002(r) requires EPA to explore the 
desirability and feasibility of establishing regulations or other 
incentives or disincentives for reducing or eliminating the generation 
of hazardous waste. In 1990, the PPA reinforced these policies by 
declaring it ``to be the national policy of the United States that 
pollution should be prevented at the source whenever feasible'' and, 
when not feasible, waste should be recycled, treated, or disposed of--
in that order of preference.
    Although the Agency has devoted significant effort to evaluation 
and promotion of waste minimization in the past 1, the Hazardous 
Waste Minimization and Combustion Strategy, first announced in May 
1993, recently provided a new impetus to this effort. The Strategy had 
several components, among which was reducing the amount and toxicity of 
hazardous waste generated in the United States. Other components of the 
Strategy included strengthening controls on emissions from hazardous 
waste combustion units; enhancing public participation in facility 
permitting; establishing risk assessment policies with respect to 
facility permitting; and continued emphasis on strong compliance and 
enforcement.
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    \1\ For example, EPA prepared a report to Congress, 
``Minimization of Hazardous Wastes'' (October 1986), that summarized 
existing waste minimization activities and evaluated options for 
promoting waste minimization.
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    EPA held a National Roundtable and four Regional Roundtables 
throughout the nation in 1993-94 to facilitate a broad dialogue on the 
spectrum of waste minimization and combustion issues. The major 
messages from these Roundtables became the building blocks for EPA's 
further efforts to promote source reduction and recycling and 
specifically for EPA's Waste Minimization National Plan, released in 
November 1994.
    The Waste Minimization National Plan focuses on the goal of 
reducing persistent, bioaccumulative, and toxic constituents in 
hazardous waste nationally by 25 percent by the year 2000 and 50 
percent by the year 2005. The central themes of the National Plan are: 
(1) Developing a framework for setting national priorities for the 
minimization of hazardous waste; (2) promoting multimedia environmental 
benefits and preventing cross-media transfers; (3) demonstrating a 
strong preference for source reduction by shifting attention to 
hazardous waste generators to reduce generation at its source; (4) 
defining and tracking progress in minimizing the generation of wastes; 
and (5) involving citizens in waste minimization implementation 
decisions. The Agency intends to continue its pursuit of hazardous 
waste minimization under the National Plan and other Agency initiatives 
in concert with the actions proposed in today's rule.
    Of the 3.0 million tons of hazardous waste combusted in 1991, 
approximately two-thirds of that amount were combusted at on-site 
facilities (i.e., the same facilities at which the waste was 
generated). Combustion at an on-site facility therefore presents a 
situation in which the same facility owners and operators may have some 
measure of control over generation of wastes at its source and its 
ultimate disposition. Although close to 400 industries generated wastes 
destined for combustion in 1991, much of the quantity was concentrated 
in a few sectors. As a companion to this proposed rule, EPA is focusing 
its waste minimization efforts on reducing the generation and 
subsequent release to the environment of the most persistent, 
bioaccumulative, and toxic constituents in hazardous wastes (i.e., 
metals, halogenated organics).
    Analysis of waste minimization potential suggests that generators 
currently burning wastes may have a number of options for eliminating 
or reducing these wastes. We believe that roughly 15 percent of all 
combusted wastes may be amenable to waste minimization. Three waste 
generating processes appear to have the most potential in terms of 
tonnage reduction: (1) Solvent and product recovery/distillation 
procedures, primarily in the organic chemicals industry, (2) product 
processing wastes, and (3) process waste removal and cleaning. In 
addition, preliminary analyses of Toxics Release Inventory and 
hazardous waste stream data indicate that over 3 million pounds of 
hazardous metals are contained in waste streams being combusted. The 
top 5 ranking metals (with respect to health risk considering 
persistence, bioaccumulation, and toxicity) are mercury, cadmium, lead, 
copper, and selenium. Additional analyses are underway to identify the 
industry sectors and production processes that are chief sources of 
these and other high priority hazardous constituents.2
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    \2\ USEPA, Office of Solid Waste, ``Setting Priorities for 
Hazardous Waste Minimization'', July 1994.
---------------------------------------------------------------------------

    In today's rule, EPA is soliciting comment on two options to 
promote the use of pollution prevention/waste minimization measures as 
methods for helping meet MACT standards. These options (regarding feed 
stream analysis and permitting requirements) are described in Part 
Five, Section VI, Subsection D of this preamble. EPA is also seeking 
comment on a proposal to consider, on a case-by-case basis, extending 
the compliance deadlines for this rule by one year if a facility can 
show that extra time is needed to implement pollution prevention/waste 
minimization measures in order for the facility to meet the MACT 
standards and that implementation cannot be practically achieved within 
the allotted three-year period after promulgation of this rule (see 
Part V, Section 1, Subsection C).

PART TWO: DEVICES THAT WOULD BE SUBJECT TO THE PROPOSED EMISSION 
STANDARDS

I. Hazardous Waste Incinerators

A. Overview

    A hazardous waste incinerator is an enclosed, controlled flame 
combustion

[[Page 17362]]

device, as defined in 40 CFR 260.10, and is used to treat primarily 
organic and/or aqueous wastes. These devices may be in situ (fixed), or 
consist of mobile units (such as those used for site remediation and 
superfund clean-ups) or may consist of units burning spent or unusable 
ammunition and/or chemical agents that meet the incinerator definition.

B. Summary of Major Incinerator Designs

    The following is a brief description of the typical incinerator 
designs used in the United States.3
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    \3\ For a more detailed description of incineration technology, 
see ``Combustion Emissions Technical Resource Document (CETRED)'', 
USEPA EPA530-R-94-014, May 1994.
---------------------------------------------------------------------------

1. Rotary Kilns
    Rotary kiln systems typically contain two incineration chambers: 
the rotary kiln and an afterburner. The kiln itself is a cylindrical 
refractory-lined steel shell 10-20 feet in diameter, with a length-to-
diameter ratio of 2 to 10. The shell is supported by steel trundles 
that ride on rollers, allowing the kiln to rotate around its horizontal 
axis at a rate of 1-2 revolutions per minute. Wastes are fed directly 
at one end of the kiln and heated by primary fuels. Waste continues to 
heat and burn as it travels down the inclined kiln. Combustion air is 
provided through ports on the face of the kiln. The kiln typically 
operates at 50-200 percent excess air and temperatures of 1600-
1800 deg.F. Flue gas from the kiln is routed to an afterburner 
operating at 2000-2500 deg.F and 100-200 percent excess air where 
unburnt components of the kiln flue gas are more completely combusted. 
Auxiliary fuel and/or pumpable liquid wastes are typically used to 
maintain the afterburner temperature.
    Some rotary kiln incinerators, known as slagging kilns, operate at 
high enough temperatures such that residual materials leave the kiln in 
a molten slag form. The molten residue is then water-quenched. Another 
kiln, an ashing kiln, operates at a lower temperature, producing a 
residual ash, which leaves as a dry material.
2. Liquid Injection Incinerators
    A liquid injection incinerator system consists of an incineration 
chamber, waste burner and auxiliary fuel system. The combustion chamber 
is a cylindrical steel shell lined with refractory material and mounted 
horizontally or vertically. Liquid wastes are atomized as they are fed 
into the combustion chamber through waste burner nozzles. Typical 
combustion chamber temperatures are 1300-3000 deg.F and residence times 
are from 0.5 to 3 seconds.
3. Fluidized Bed Incinerators
    A fluidized bed system is essentially a vertical cylinder 
containing a bed of granular material at the bottom. Combustion air is 
introduced at the bottom of the cylinder and flows up through the bed 
material, suspending the granular particles. Waste and auxiliary fuels 
are injected into the bed, where they mix with combustion air and burn 
at temperatures from 840-1500 deg.F. Further reaction occurs in the 
volume above the bed at temperatures up to 1800 deg.F.
4. Fixed Hearth Incinerators
    Fixed hearth incinerators typically contain two furnace chambers: a 
primary and a secondary chamber. Some designs have two or three step 
hearths on which ash and waste are pushed with rams through the system. 
A controlled flow `underfire' combustion air is introduced up through 
the hearths. The primary chamber operates in ``starved air'' mode and 
the temperatures are around 1000 deg.F. The unburnt hydrocarbons reach 
the secondary chamber where 140-200 percent excess air is supplied and 
temperatures of 1400-2000 deg.F are achieved for more complete 
combustion.

C. Number of Incinerator Facilities

    Currently, 162 permitted or interim status incinerator facilities, 
having 190 units, are in operation in the U.S. Another 26 facilities 
are proposed 4 (i.e., new facilities under construction or 
permitting). Of the above 162 facilities, 21 facilities are commercial 
facilities that burn about 700,000 tons of hazardous waste annually. 
The remaining 141 are on-site or captive facilities and burn about 
800,000 tons of waste annually.
---------------------------------------------------------------------------

    \4\ USEPA ``List of hazardous waste incinerators,'' November 
1994.
---------------------------------------------------------------------------

D. Typical Emission Control Devices for Incinerators

    Incinerators are equipped with a wide variety of air pollution 
control devices (APCDs), which range from no control (for devices 
burning low ash and low chlorine wastes) to sophisticated state-of-the-
art units providing control for several pollutants. Hot flue gases from 
the incinerators are cooled and cleaned of the air pollutants before 
they exit the stack. Cooling is mostly done by water quenching, wherein 
atomized water is sprayed directly into the hot gases. The cooled gases 
are passed through various pollution control devices to control PM, 
metals and organic emissions to desired or required levels. Most 
incinerators use wet APCDs to scrub acid emissions (3 facilities use 
dry scrubbers). Typical APCDs used include packed towers, spray dryers, 
or dry scrubbers for acid gas (e.g., HCl, Cl2) control, and 
venturi-scrubbers, wet or dry electrostatic precipitators (ESPs) or 
fabric filters for particulate control.
    Activated carbon injection for controlling dioxin and mercury is 
being used at only one incinerator. Newer APC technologies (such as 
catalytic oxidizers and dioxin/furan inhibitors) have recently emerged, 
but have not been used on any full scale facilities in the U.S. For 
detailed description of APCDs, see Appendix A of ``Combustion Emissions 
Technical Resource Document (CETRED),'' US EPA Document #EPA530-R-94-
014, May 1994.

II. Hazardous Waste-Burning Cement Kilns

A. Overview of Cement Manufacturing

    Cement refers to the commodities that are produced by heating 
mixtures of limestone and other minerals or additives at high 
temperature in a rotary kiln, followed by cooling, grinding, and finish 
mixing. This is the manner in which the vast majority of commercially-
important cementitious materials are produced in the United States. 
Cements are used to chemically bind different materials together. The 
most commonly produced cement type is ``Portland'' cement, though other 
standard cement types are also produced on a limited basis (e.g., 
sulfate-resisting, high-early-strength, masonry, waterproofed). 
Portland cement is a hydraulic cement, meaning that it sets and hardens 
by chemical interaction with water. When combined with sand, gravel, 
water, and other materials, Portland cement forms concrete, one of the 
most widely used building and construction materials in the world. 
Cement produced and sold in the U.S. must meet specifications 
established by the American Society for Testing and Materials (ASTM). 
Each type requires specific additives or changes in the proportions of 
the raw material mix to make products for specific applications.

B. Summary of Major Design and Operating Features of Cement Kilns

    Cement kilns are horizontally inclined rotating cylinders, 
refractory-brick lined, and internally-fired, that calcine a blend of 
raw materials

[[Page 17363]]

containing calcium (typically limestone), silica and alumina (typically 
clay, shale, slate, and/or sand), and iron (typically steel mill scale 
or iron ore) to produce Portland cement. Generally, there is a wet 
process and a dry process for producing cement. In the wet process, the 
limestone and shale are ground up, wetted and fed into the kiln as a 
slurry. In the dry process, raw materials are ground dry and fed into 
the kiln dry. Wet process kilns are typically longer than dry process 
kilns in order to facilitate water evaporation from the slurried raw 
material. Wet kilns can be more than 450 feet in length. Dry kilns are 
more thermally efficient and frequently use preheaters or precalciners 
to begin the calcining process (i.e., the essential function of driving 
CO2 from raw materials) before the raw materials are fed into the 
kiln.
    Combustion gases and raw materials move in a counterflow direction, 
with respect to each other, inside a cement kiln. The kiln is inclined, 
and raw materials are fed into the upper end (i.e., the ``cold'' end) 
while fuels are normally fired into the lower end (i.e., the ``hot'' 
end). Combustion gases move up the kiln counter to the flow of raw 
materials. The raw materials get progressively hotter as they travel 
down the length of the kiln. The raw materials eventually begin to 
soften and fuse at temperatures between 2,250 and 2,700  deg.F to form 
the clinker product. Clinker is then cooled, ground, and mixed with 
other materials, such as gypsum, to form cement.
    Combustion gases leaving the kiln typically contain from 6 to 30 
percent of the free solids as dust, which are often recycled to the 
kiln feed system, though the extent of recycling varies greatly among 
cement kilns.
    Dry kilns with a preheater (PH) or precalciner (PC) often use a by-
pass duct to remove from 5 to 30 percent of the kiln off-gases from the 
main duct. The by-pass gas is passed through a separate air pollution 
control system to remove particulate matter. Collected by-pass dust is 
not reintroduced into the kiln system to avoid a build-up of metal 
salts that can affect product quality.
    Some cement kilns burn hazardous waste-derived fuels to replace 
from 25 to 100 percent of normal fossil fuels (e.g., coal). Most kilns 
burn liquid waste fuels but several also burn bulk solids and small 
(e.g., six gallon) containers of viscous or solid hazardous waste 
fuels. Containers are introduced either at the upper, raw material end 
of the kiln or at the midpoint of the kiln. EPA has also found that 
hazardous waste-fired precalciners can still be considered part of the 
cement kiln and, thus, would be part of an industrial furnace (per the 
definition in 40 CFR 260.10). See 56 FR at 7184-85 (February 21, 1991). 
This finding is codified at Sec. 266.103(a)(5)(I)(c). This is the only 
time (and the only rulemaking) in which the Agency found that a device 
not enumerated in the list of industrial furnaces in Sec. 260.10 can be 
considered part of the industrial furnace when it burns hazardous 
wastes separate from those burned in the main combustion device.

C. Number of Facilities

    The Agency has emissions data from 26 facilities representing 49 
cement kilns in the U.S. It should be noted that some facilities no 
longer burn or process hazardous waste since they were required to 
certify compliance with the BIF regulations in August 1992.
    Of the hazardous waste-burning kilns for which we have emissions 
data, 14 facilities use a wet process, 5 facilities use a dry process, 
and the remaining 7 facilities employ either preheaters or preheater/
precalciners in the cement manufacturing process.

D. Emissions Control Devices

    All hazardous waste-burning cement kilns either use fabric filters 
(baghouses) or electrostatic precipitators (ESPs) as air pollution 
control devices. ESPs have traditionally been employed in the cement 
industry and are currently used at 17 of the facilities. Nine 
facilities use fabric filters. A detailed description of these and 
other air pollution control devices is contained in the technical 
support document. 5
---------------------------------------------------------------------------

    \5\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume I: Description of Source Categories'', February 
1996.
---------------------------------------------------------------------------

III. Hazardous Waste-Burning Lightweight Aggregate Kilns

A. Overview of Lightweight Aggregate Kilns (LWAKs)

    The term lightweight aggregate refers to a wide variety of raw 
materials (such as clay, shale, or slate) which after thermal 
processing can be combined with cement to form concrete products. 
Lightweight aggregate concrete is produced either for structural 
purposes or for thermal insulation purposes. A lightweight aggregate 
plant is typically composed of a quarry, a raw material preparation 
area, a kiln, a cooler, and a product storage area. The material is 
taken from the quarry to the raw material preparation area and from 
there is fed into the rotary kiln.

B. Major Design and Operating Features

    A rotary kiln consists of a long steel cylinder, lined internally 
with refractory bricks, which is capable of rotating about its axis and 
is inclined at an angle of about 5 degrees to the horizontal. The 
length of the kiln depends in part upon the composition of the raw 
material to be processed but is usually 30 to 60 meters. The prepared 
raw material is fed into the kiln at the higher end, while firing takes 
place at the lower end. The dry raw material fed into the kiln is 
initially preheated by hot combustion gases. Once the material is 
preheated, it passes into a second furnace zone where it melts to a 
semiplastic state and begins to generate gases which serve as the 
bloating or expanding agent. In this zone, specific compounds begin to 
decompose and form gases such as SO2, CO2, SO3, and 
O2 that eventually trigger the desired bloating action within the 
material. As temperatures reach their maximum (approximately 
2100 deg.F), the semiplastic raw material becomes viscous and entraps 
the expanding gases. This bloating action produces small, unconnected 
gas cells, which remain in the material after it cools and solidifies. 
The product exits the kiln and enters a section of the process where it 
is cooled with cold air and then conveyed to the discharge.
    Kiln operating parameters such as flame temperature, excess air, 
feed size, material flow, and speed of rotation vary from plant to 
plant and are determined by the characteristics of the raw material. 
Maximum temperature in the rotary kiln varies from 2050  deg.F to 2300  
deg.F, depending on the type of raw material being processed and its 
moisture content. Exit temperatures may range from 300  deg.F to 1200  
deg.F, again depending on the raw material and on the kiln's internal 
design. Approximately 80 to 100 percent excess air is forced into the 
kiln to aid in expanding the raw material.

C. Number of Facilities

    EPA has identified 36 lightweight aggregate kiln locations in the 
United States. Of these, EPA has identified seven facilities that are 
currently burning hazardous waste in a total of 15 kilns.

D. Air Pollution Control Devices

    Lightweight aggregate kilns use one or a combination of air 
pollution control devices, including fabric filters, venturi scrubbers, 
spray dryers, cyclones and wet scrubbers. All of the facilities utilize 
fabric filters as the main type of emissions control, although one 
facility uses a spray dryer, venturi scrubber and

[[Page 17364]]

wet scrubber in addition to a fabric filter. For detailed descriptions 
of these and other air pollution control devices, please see Appendix A 
of the draft EPA document Combustion Emissions Technical Resource 
Document (CETRED). 6
---------------------------------------------------------------------------

    \6\ USEPA, ``Draft Combustion Emission Technical Resource 
Document (CETRED)'', EPA 530-R-94-014, May 1994.
---------------------------------------------------------------------------

PART THREE: DECISION PROCESS FOR SETTING NATIONAL EMISSION STANDARDS 
FOR HAZARDOUS AIR POLLUTANTS (NESHAPs)

I. Source of Authority for NESHAP Development

    The 1990 Amendments to the Clean Air Act significantly revised the 
requirements for controlling emissions of hazardous air pollutants. EPA 
is now required to develop a list 7 of categories of major and 
area sources 8 of the hazardous air pollutants (HAPs) enumerated 
in section 112 and to develop technology-based performance standards 
for such sources over specified time periods. See Clean Air Act (the 
Act or CAA) Secs. 112(c) and 112(d). Section 112 of the Act replaces 
the previous system of pollutant-by-pollutant health-based regulation 
that proved ineffective at controlling the high volumes, 
concentrations, and threats to human health and the environment posed 
by HAPs in air emissions. See generally S. Rep. No. 228, 101st Cong. 
1st Sess. 128-32 (1990).
---------------------------------------------------------------------------

    \7\ The Agency published an initial list of categories of major 
and area sources of HAPs on July 16, 1992. See 57 FR 31576.
    \8\ See Part Three, Section III of today's proposal for a 
discussion of major and area sources. Generally, a major source is a 
stationary source that emits, or has the potential to emit 
considering controls, 10 tons per year of a HAP or 25 tons per year 
of a combination of HAPs. CAA Sec. 112(a)(1). An area source is 
generally a stationary source that is not a major source. Id. 
Sec. 112(a)(2).
---------------------------------------------------------------------------

    Section 112(f) also requires the Agency to report to Congress by 
the end of 1996 on estimated risk remaining after imposition of 
technology-based standards and to make recommendations as to 
legislation to address such risk. CAA Sec. 112(f)(1). If Congress does 
not act on the recommendation, then EPA must address any significant 
remaining residual risks posed by sources subject to the section 112(d) 
technology-based standards within 8 years after promulgation of these 
standards. See Sec. 112(f)(2). The Agency is required to impose 
additional controls if such controls are needed to protect public 
health with an ample margin of safety, or to prevent adverse 
environmental effects. Id. In addition, if the technology-based 
standards for carcinogens do not reduce the lifetime excess cancer risk 
for the most exposed individual to less than one in a million 
(1 x 10-6), then the Agency must promulgate additional standards. 
See Sec. 112(f)(2)(A).

II. Procedures and Criteria for Development of NESHAPs

    NESHAPs are developed in order to control HAP emissions from both 
new and existing sources according to the statutory directives set out 
in Sec. 112. The statute requires a NESHAP to reflect the maximum 
degree of reduction of HAP emissions that is achievable taking into 
consideration the cost of achieving the emission reduction, any non-air 
quality health and environmental impacts, and energy requirements. 
Sec. 112(d)(2). In regulatory parlance, these are often referred to as 
maximum achievable control technology (or MACT) standards.
    The Clean Air Act establishes minimum levels, usually referred to 
as MACT floors, for the emission standards. Section 112(d)(3) requires 
that MACT floors be determined as follows: for existing sources in a 
category or sub-category with 30 or more sources, the MACT floor cannot 
be less stringent than the ``average emission limitation achieved by 
the best performing 12 percent of the existing sources * * *''; for 
existing sources in a category or sub-category with less than 30 
sources, then the MACT floor cannot be less stringent than the 
``average emission limitation achieved by the best performing 5 sources 
* * *''; for new sources, the MACT floor cannot be ``less stringent 
than the emission control that is achieved by the best controlled 
similar source * * *''. See Sec. 112(d)(3) (A) and (B).
    EPA must, of course, consider in all cases whether to develop 
standards that are more stringent than the floor (``beyond the floor'' 
standards). To do so, however, EPA must consider the enumerated 
statutory criteria such as cost, energy, and non-air environmental 
implications.
    Emission reductions may be accomplished through application of 
measures, processes, methods, systems, or techniques, including, but 
not limited to: (1) Reducing the volume of, or eliminating emissions 
of, such pollutants through process changes, substitution of materials, 
or other modifications; (2) enclosing systems or processes to eliminate 
emissions; (3) collecting, capturing, or treating such pollutants when 
released from a process, stack, storage, or fugitive emissions point; 
(4) design, equipment, work practice, or operational standards 
(including requirements for operator training or certification); or (5) 
any combination of the above. See Sec. 112(d)(2).
    Application of techniques (1) and (2) of the previous paragraph are 
consistent with the definitions of pollution prevention under the 
Pollution Prevention Act and the definition of waste minimization under 
RCRA/HSWA. These terms have particular applicability in the discussion 
of pollution prevention/waste minimization options presented in the 
permitting and compliance sections of today's proposal.
    To develop a NESHAP, the EPA compiles available information and in 
some cases collects additional information about the industry, 
including information on emission source quantities, types and 
characteristics of HAPs, pollution control technologies, data from HAP 
emissions tests (e.g., compliance tests, trial burn tests) at 
controlled and uncontrolled facilities, and information on the costs 
and other energy and environmental impacts of emission control 
techniques. EPA uses this information in analyzing and developing 
possible regulatory approaches. EPA, of course, does not always have or 
collect the same amount of information per industry, but rather bases 
the standard on information practically available.
    Although NESHAPs are normally structured in terms of numerical 
emission limits--the preferred means of establishing standards--
alternative approaches are sometimes necessary and appropriate. In some 
cases, for example, physically measuring emissions from a source may be 
impossible, or at least impractical, because of technological and 
economic limitations. Section 112(h) authorizes the Administrator to 
promulgate a design, equipment, work practice, or operational standard, 
or a combination thereof, in those cases where it is not feasible to 
prescribe or enforce an emissions standard.
    EPA is required to develop emission standards based on performance 
of maximum achievable control technology for categories or sub-
categories of major sources of hazardous air pollutants. 
Sec. 112(d)(1). As explained more fully in the following section, a 
major source emits, or has the potential to emit considering controls, 
either 10 tons per year of any hazardous air pollutant or 25 tons or 
more of any combination of those pollutants. Sec. 112(a)(1). EPA also 
can establish lower thresholds where appropriate. Id. EPA

[[Page 17365]]

may in addition require sources emitting particularly dangerous 
hazardous air pollutants (such as particular chlorinated dioxins and 
furans) to be regulated under the MACT standards for major sources. 
Sec. 112(c)(6).
    Area sources are any source which is not a major source. Such 
sources must be regulated by technology-based standards if they are 
listed, pursuant to Sec. 112(c)(3), based on the Agency's finding that 
these sources (individually or in the aggregate) present a threat of 
adverse effects to human health or the environment warranting 
regulation. After such a determination, the Agency has a further choice 
as to require technology-based standards based on MACT or on generally 
achievable control technology (GACT). Sec. 112(d)(5).
    In this rulemaking, EPA is proceeding pursuant to Sec. 112(c)(6) 
(i.e., imposing MACT controls on area sources), because these hazardous 
waste combustion units emit a number of the HAPs singled out in that 
provision, including the enumerated dioxins and furans, mercury, and 
polycyclic organic matter. (See discussion below.)

III. List of Categories of Major and Area Sources

A. Clean Air Act Requirements

    As just discussed, Section 112 of the CAA requires that the EPA 
promulgate regulations requiring the control of hazardous air 
pollutants emissions associated with categories or subcategories of 
major and area sources. These source categories and subcategories are 
to be listed pursuant to Sec. 112(c)(1). EPA published an initial list 
of 174 categories of such major and area sources in the Federal 
Register on July 16, 1992 (57 FR 31576).

B. Hazardous Waste Incinerators

    ``Hazardous waste incinerators'' is one of the 174 categories of 
sources listed. The category consists of commercial and on-site 
(including captive) incinerating facilities. The listing was based on 
the Administrator's determination that at least one hazardous waste 
incinerator may reasonably be anticipated to emit several of the 189 
listed HAPs in quantities sufficient to designate them as major 
sources. EPA used two emission rate values to evaluate the available 
hazardous waste incinerator emissions data: the maximum emission rate 
measured during the compliance test, and the average emission rate. The 
data indicate that approximately 30 percent of the facilities meet the 
major source criteria when using the maximum emissions rate value. When 
using the average emissions rate value approximately 15 percent of 
facilities meet the major source criteria.9 Those facilities 
meeting the major source criteria do so for HCl and Cl2 emissions, 
and one facility is also a major source for antimony emissions.
---------------------------------------------------------------------------

    \9\ For further details see USEPA, ``Draft Technical Support 
Document for HWC MACT Standards, Volume I: Description of Source 
Categories'', February 1996.
---------------------------------------------------------------------------

    It should be noted that a major source and boundary for considering 
whether a source is a major includes all potential emission points of 
HAPs at that contiguous facility, including storage tanks, equipment 
leaks, and other hazardous waste handling facilities. The above 
calculations for incinerators on whether a source is a major source 
under Sec. 112 do not reflect these potential emission points.
    Notwithstanding the fact that most HW incinerators are not likely 
to meet the HAP emission thresholds for major sources, the Agency is 
proposing to subject all HWCs to regulation under MACT as major 
sources, under the authority of Sec. 112(c)(6). See Section IV below.

C. Cement Kilns

    Another of the 174 categories of major and area sources of HAPs is 
Portland Cement Manufacturing (cement kilns). In evaluating the 
emissions data for the hazardous waste-burning cement kilns, 85 percent 
of the cement kilns were determined to meet the major source criteria 
when using the maximum emission rate value. Using the average emission 
rate value, just over 80 percent of the hazardous waste-burning cement 
kilns meet the major source criteria.10 Those facilities meeting 
the major source criteria do so for HCl and Cl2 emissions, and one 
facility is also a major source for organic emissions. It should be 
noted that the calculation on whether a cement kiln is a major source 
did not include potential emission points of HAPs at that contiguous 
facility.
---------------------------------------------------------------------------

    \10\ Ibid.
---------------------------------------------------------------------------

    Notwithstanding the fact that some hazardous waste-burning cement 
kilns may not meet the definition of major source, the Agency is 
proposing to subject all HWCs to regulation under MACT, as major 
sources, under the authority of Sec. 112(c)(6). See Section IV below.

D. Lightweight Aggregate Kilns

    Section 112(c)(5) authorizes EPA to amend the source category list 
at any time to add categories or subcategories that meet the listing 
criteria. EPA is proposing to exercise that authority by adding HW-
burning lightweight aggregate kilns to the list of source categories.
    In analyzing the emissions data, EPA found that all hazardous 
waste-burning LWAKs met the major source criteria for two HAPs, HCl and 
Cl2, using either the average or maximum emission rate 
value.11 It should be noted that the calculation on whether a LWAK 
is a major source did not include potential emission points of HAPs at 
that contiguous facility. EPA is therefore proposing today the addition 
of hazardous waste-burning LWAKs as a source category in accordance 
with section 112(c)(5) of the Act. In addition, as discussed below, 
even if a LWAK would otherwise be an area source, EPA is proposing to 
subject it to the same NESHAPS as major LWAK sources.
---------------------------------------------------------------------------

    \11\ Ibid.
---------------------------------------------------------------------------

IV. Proposal To Subject Area Sources to the NESHAPs Under Authority of 
Section 112(c)(6)

    EPA is today proposing to subject all hazardous waste incinerators, 
hazardous waste-burning cement kilns, and hazardous waste-burning 
lightweight aggregate kilns (i.e., both area and major sources) to 
regulation as major sources pursuant to CAA Sec. 112(c)(6). That 
provision states that, by November 15, 2000, EPA must list and 
promulgate Sec. 112 (d)(2) or (d)(4) standards (i.e., standards 
reflecting MACT) for categories (and subcategories) of sources emitting 
specific pollutants, including the following HAPs emitted by HWCs: 
polycyclic organic matter, mercury, 2,3,7,8-tetrachlorodibenzofuran, 
and 2,3,7,8-tetrachlorodibenzo-p-dioxin. (Although the Agency has not 
prepared the list, it is the Agency's intention to include hazardous 
waste combustors.) EPA must assure that sources accounting for not less 
than 90 percent of the aggregate emissions of each enumerated pollutant 
are subject to MACT standards.
    The chief practical effect of invoking Sec. 112(c)(6) for this 
rulemaking is to subject area sources that emit 112(c)(6) pollutants to 
the same MACT standards as major sources, rather than to the 
potentially less stringent 112(d)(5) or ``GACT'' (``generally 
achievable control technology'') standards.12 Today's proposal 
constitutes one of many EPA actions to assure that sources accounting 
for at least 90 percent of

[[Page 17366]]

emissions of Sec. 112(c)(6) pollutants are subject to MACT standards.
---------------------------------------------------------------------------

    \12\ EPA also solicits comment on an alternative reading of 
Sec. 112(c)(6), whereby the provision would require MACT control for 
the enumerated pollutants but not necessarily for other HAPs emitted 
by the source, which HAPs are not enumerated in Sec. 112(c)(6).
---------------------------------------------------------------------------

    Although Sec. 112(c)(6) requires the Agency to regulate source 
categories that emit not less than 90 percent of the aggregate 
emissions of the high priority HAPs, the Agency will use its discretion 
to avoid regulating area source categories with trivial aggregate 
emissions of specific Sec. 112(c)(6) HAPs. However, as an example of 
the emissions that are possible from the HWC source categories, it is 
estimated that HWCs presently emit in aggregate 11.1 tons of mercury 
per year. Of this quantity, 4.6 tons per year can be attributed to 
hazardous waste incinerators and 6.5 tons per year to hazardous waste-
burning cement and lightweight aggregate kilns. Also, it is estimated 
that HWCs presently emit in aggregate 122 pounds of dioxins/furans (or 
2.15 pounds TEQ) per year. Of this quantity, 9 pounds (or 0.2 pounds 
TEQ) per year can be attributed to hazardous waste incinerators and 113 
pounds (or 1.95 pounds TEQ) per year to hazardous waste-burning cement 
and lightweight aggregate kilns. To show an example of how today's 
proposal constitutes an action to assure that sources accounting for at 
least 90 percent of emissions of Sec. 112(c)(6) pollutants are subject 
to MACT standards, the document Estimating Exposure to Dioxin-Like 
Compounds, Vol. II: Properties, Sources, Occurrence and Background 
Exposures (EPA, 1994) estimates (on p. 29) that national emissions of 
dioxins and furans (D/F) total 4.18 pounds TEQ per year. Based on this 
estimation, HWCs account for 51 percent of the annual national 
emissions of D/F. (Consequently, EPA expects these source categories to 
be included in the list of sources to be controlled to achieve the 
requisite 90 percent reduction in aggregate emissions of section 
112(c)(6) pollutants.)
    Congress singled out the HAPs enumerated in Sec. 112(c)(6) as being 
of ``specific concern'' not just because of their toxicity but because 
of their propensity to cause substantial harm to human health and the 
environment via indirect exposure pathways (i.e., from the air through 
other media, such as water, soil, food uptake, etc.). S. Rep. No. 228, 
101st Cong. 1st Sess., pp. 155, 166. These pollutants have exhibited 
special potential to bioaccumulate, causing pervasive environmental 
harm in biota (and, ultimately, human health risks). Id. Indeed, as 
discussed later, the data appear to show that much of the human health 
risk from emissions of these HAPs from HWCs comes from these indirect 
exposure pathways. Id. at p. 166. Congress' express intention was to 
assure that sources emitting significant quantities of Sec. 112(c)(6) 
pollutants received a stricter level of control. Id.

V. Selection of MACT Floor for Existing Sources

    The starting point in developing MACT standards is determining 
floor levels, i.e. the minimum (least stringent) level at which the 
standard can be set.
    All of the hazardous waste combustion units subject to this 
proposed rule are already subject to RCRA regulation under 40 CFR Parts 
264, 265, or 266. As a result, the Agency has a substantial amount of 
data reflecting performance of these devices. These data consist 
largely of trial burn data for hazardous waste incinerators and data 
from certifications of compliance for hazardous waste-burning cement 
kilns and LWAKs obtained pursuant to 266.103(c). These data consist of 
at least three runs for any given test condition.
    In using these ``short term'' test data to establish a MACT floor, 
the Agency has developed an approach that ensures the standards are 
achievable, i.e. reflect the performance over time of properly designed 
and operated air pollution control devices (or operating practices) 
taking into account intrinsic operating variability.
    In addition, the Agency notes that the floor calculations were 
performed on individual HAPs or, in the case of metals, in two groups 
of HAPs that behave similarly (i.e., separate floor levels for each 
hazardous air pollutant or group of metal pollutants). However, for 
HAPs that are controlled by the same type of air pollution control 
device (APCD), EPA has ensured that all HAP floors are simultaneously 
achievable by identifying the APCD and APCD treatment train that can be 
used to meet all floor levels. The ultimate floor levels thus derived 
can be achieved using the identified technology. This approach is 
consistent with methods used by EPA in other rules to calculate MACT 
requirements where the HAP species present must be treated by a 
treatment train. See, e.g., MACT Rules for Secondary Lead Smelters. 60 
FR 32589 (June 23, 1995).
    The Agency is not, however, treating hazardous waste-burning 
incinerators, cement kilns, and LWAKs as a single source category for 
purposes of developing the MACT floor (or for any other purpose). The 
Agency's initial view is that there are technical differences in 
performance for particular HAPs among the three source categories, and 
therefore that the technology-based floors must reflect these operating 
differences.

A. Proposed Approach: Combined Technology-Statistical Approach

    This analysis first identified the best performing control 
technology(ies) for each source category (i.e., incinerators, cement 
kilns, and lightweight aggregate kilns) and each HAP of concern by 
arraying from lowest to highest all the particular HAP emissions data 
from existing units within the source category by test condition 
averages. These technologies comprise MACT floor. In cases where a 
source had emissions data for a HAP from several different test 
conditions of a compliance test, the Agency arrayed each test condition 
separately. The Agency then identified the emission control technology 
or technologies (and normalized feedrate of metals and chlorine in 
hazardous waste) used by sources with emissions levels at or below the 
level emitted by the median of the best performing 12 percent of 
sources. The sources are termed ``the best performing 6 percent'' of 
the sources, or ``MACT pool'', and the controls they use comprise MACT 
floor.
    The next step was to identify an emissions level that MACT floor 
control could achieve. Thus, emissions data from all sources (in the 
source category) that use MACT floor control were arrayed in ascending 
order by average emissions. [This is referred to as the ``expanded MACT 
pool'' or ``expanded universe''.] The Agency evaluated the control 
technologies used by the additional sources within the ``expanded 
universe'' as available data allowed to ensure that they were in fact 
equivalent in design to MACT floor. The Agency then selected the test 
condition in the expanded MACT pool with the highest mean emissions to 
identify the emission level that MACT floor could achieve.
    Because the emissions database was comprised of ``short-term'' test 
data, the Agency used a statistical approach to identify an emission 
level that MACT floor could achieve routinely. The Agency then 
identified the test condition in the expanded MACT pool with the 
highest mean emissions to statistically calculate a ``design level'' 
and a floor standard. The design level was calculated as the log mean 
of the emissions for the test condition. The standard was calculated as 
a level that a source (that is designed and operated to routinely meet 
the design level) could meet 99 percent of the time if it has the 
average within-test-condition emissions variability of the expanded 
MACT pool. Although the Agency evaluated 90th and 95th percentile 
limits, the 99th

[[Page 17367]]

percentile limit was chosen to: (1) More accurately reflect the 
variability that could be present in emissions data, and (2) 
appropriately characterize this variability in light of the consequence 
of failing to achieve the emissions standards. Additional information 
on how MACT floor levels were identified is provided in the ``Draft 
Technical Support Document for HWC MACT Standards, Volume III: 
Selection of Proposed MACT Standards and Technologies''.
    In accounting for operating variability, the Agency solicits 
comment on whether it may have overcompensated so that the identified 
floor levels are unduly lenient. The test data on which the proposal is 
based to some extent reflect worst-case performance conditions because 
RCRA sources try to obtain maximum operating flexibility by conducting 
test burns at extreme operating conditions. For example, many sources 
spike wastes with excess metals and chlorine during compliance testing. 
In addition, sources operate their emissions control devices under low 
efficiency conditions (while still meeting emission standards) to 
ensure lenient operating limits. It thus may be that the Agency's 
emissions database is so inflated that separate consideration of 
emissions variability may not be warranted. A floor level could be the 
highest mean of the test conditions in the expanded MACT pool.
    The Agency emphasizes that it would be preferable, for purposes of 
setting these MACT standards, to have operational and emissions data 
that better reflect long-term, more routine day-to-day facility 
operations from all of the source categories. We believe that this type 
of data would enable the MACT process to articulate a set of HAP 
standards that would not create some of the issues raised in subsequent 
sections of this preamble (such as the most appropriate resolution of a 
variability factor, the optimum approach for considering the 
contribution of cement and lightweight aggregate kiln raw material feed 
to HAP emissions, and better identification among sources that are now 
in an expanded MACT pool but which, with better data, would be 
determined not to be employing the identified floor controls). As noted 
in these subsequent sections, the Agency urges commenters to submit 
these types of data.

B. Another Approach Considered but not Used

    Although the Agency believes the proposed approach reflects a 
reasonable interpretation of the statute, there are other possible 
interpretations. One of these interpretations, termed the ``12 percent 
approach'', was raised and, in fact, evaluated during the process 
already outlined. This approach is presented here, along with the 
results of the process in Part Four, Section VIII, for public 
inspection.
    This ``12 percent approach'' was evaluated in a like manner to the 
Agency's preferred approach just described. Again, the best performing 
control technology(ies) for each source category and each HAP were 
identified by arraying the data by test condition averages. However, 
the Agency identified the technology or technologies used by the best 
performing 12 percent of the sources. After arraying emissions data 
from all facilities in the source category that use the identified MACT 
floor technology(ies) (i.e., the expanded MACT pool), the Agency 
selected an emissions floor level based on the statistical average of 
the 12 percent MACT pool, to which was added the average within-test 
condition variability within the expanded MACT pool. The emissions 
floor was then calculated at a level that a source with average 
emissions variability would be expected to achieve 99 percent of the 
time. The approach was not proposed because it could not be 
demonstrated that sources within the expanded MACT pool using MACT 
floor controls could achieve the floor levels. Again, the details of 
the statistical methods employed are presented in the ``Draft Technical 
Support Document for HWC MACT Standards, Volume III: Selection of 
Proposed MACT Standards and Technologies''.

C. Identifying Floors as Proposed in CETRED

    The discussion in the Draft Combustion Emissions Technical Resource 
Document (CETRED) (U.S. EPA, EPA530-R-94-014, May 1994) presented one 
methodology for establishing particulate matter (PM) and dioxin/furan 
(D/F) technology-based emission levels for hazardous waste combustors 
(HWCs). The document presented a procedure for establishing numerical 
levels which took into account the natural variability that was present 
in the Agency's PM and D/F emissions data. EPA received numerous 
comments on the document.
    The approaches outlined in CETRED were an initial and preliminary 
attempt to apply the process by which the NESHAPs are to be established 
for the existing types of hazardous waste combustors. The approaches in 
CETRED focused solely on the performance of MACT and how to establish 
the ``floor'' emission level under the MACT process.
    In CETRED, determination of the MACT floor involved: (1) screening 
unrepresentative data; (2) ranking all HWC sources based on the data 
average, considering variability; (3) identifying the top 12 percent of 
sources as the MACT pool; and (4) statistically evaluating the MACT 
pool to set the MACT floor. These elements and considerations are 
described in further detail in CETRED and the ``Draft Technical Support 
Document for HWC MACT Standards, Volume III: Selection of Proposed MACT 
Standards and Technologies''. The Agency specifically indicated the 
preliminary nature of the CETRED approaches and, in light of further 
deliberations and comments received, has considered and adopted other 
approaches for this proposal. The comments received are found in the 
docket.
    In considering the use of a purely statistical approach to setting 
MACT floors, the Agency recognized that whether sources could actually 
achieve a statistically-derived MACT floor level on a regular basis was 
significant in determining whether a purely statistical approach could 
be appropriate or not. The Agency encountered difficulties in 
identifying an appropriate purely statistical model for the combined 
source category (HW incinerators, HW-burning cement kilns, and HW-
burning lightweight aggregate kilns) emissions database. Consequently, 
the Agency abandoned a purely statistical approach and examined an 
approach--referred to here as the ``technology approach''--that used 
demonstrated technological capabilities as a key factor in selecting 
MACT floor levels.

D. Establishing Floors One HAP or HAP Group at a Time

    EPA believes it is permissible to establish MACT floors separately 
for individual HAPs or group of HAPs that behave the same from a 
technical standpoint (i.e., based on separate MACT pools and floor 
controls), provided the various MACT floors are simultaneously 
achievable. As set out below, Congress has not spoken to this precise 
issue. An interpretation that allows this approach is consistent with 
statutory goals and policies, as well as established EPA practice in 
developing MACT standards.
    As described earlier, Congress specified in section 112(d)(3) the 
minimum level of emission reduction that could satisfy the requirement 
to adopt MACT. For new sources, this floor level is to be ``the 
emission control that is achieved in practice by the best

[[Page 17368]]

controlled similar source''. For existing sources, the floor level is 
to be ``the average emission limitation achieved by the best performing 
12 percent of the existing sources'' for categories and subcategories 
with 30 or more sources, or ``the average emission limitation achieved 
by the best performing 5 sources'' for categories and subcategories 
with fewer than 30 sources. An ``emission limitation'' is ``a 
requirement * * * which limits the quantity, rate, or concentration of 
emissions of air pollutants'' (section 302 (k)) (although the extent, 
if any, the section 302 definitions need to apply to the terms used in 
section 112 is not clear).
    This language does not expressly address whether floor levels can 
be established HAP-by-HAP. The existing source MACT floor achieved by 
the average of the best performing 12 percent can reasonably be read as 
referring to the source as a whole or performance as to a particular 
HAP. The statutory definition of ``emission limitation'' (assuming it 
applies) likewise is ambiguous, since ``requirements limiting quantity, 
rate, or concentration of pollutants'' could apply to particular HAPs 
or all HAPs. The reference in the new source MACT floor to ``emission 
control achieved by the best controlled similar source'' can mean 
emission control as to a particular HAP or achieved by a source as a 
whole.
    Here, Congress has not spoken to the precise question at issue, and 
the Agency's interpretation effectuates statutory goals and policies in 
a reasonable manner. See Chevron v. NRDC, 467 U.S. 837 (1984) 
(indicating that such interpretations must be upheld). The central 
purpose of the amended air toxics provisions was to apply strict 
technology-based emission controls on HAPs. See, e.g., H. Rep. No. 952, 
101st Cong. 2d sess. 338. The floor's specific purpose was to assure 
that consideration of economic and other impacts not be used to ``gut 
the standards''. While costs are by no means irrelevant, they should by 
no means be the determining factors. There needs to be a minimum degree 
of control in relation to the control technologies that have already 
been attained by the best existing sources. Legislative History of the 
Clean Air Act Vol. II at 2897 (statement of Rep. Collins).
    Furthermore, an alternative interpretation would tend to result in 
least common denominator floors where multiple HAPs are emitted, 
whereby floors would no longer be reflecting performance of the best 
performing sources. For example, if the best performing 12 percent of 
facilities for HAP metals did not control organics as well as a 
different 12 percent of facilities, the floor for organics and metals 
would end up not reflecting best performance. Indeed, under this 
reading, the floor would be no control, because no plant is controlling 
both types of HAPs.
    EPA is convinced that this result is not compelled by the statutory 
text, and does not effectuate the evident statutory purpose of having 
floor levels reflect performance of an average of a group of best-
performing sources. Conversely, using a HAP-by-HAP approach (or an 
approach that groups HAPs based on technical factors) to identify 
separate floors for metals and organics in this example promotes the 
stated purpose of the floor to provide a minimum level of control 
reflecting what best performing existing sources have already 
demonstrated an ability to do.
    EPA notes, however, that if optimized performance for different 
HAPs is not technologically possible due to mutually inconsistent 
control technologies (for example, metals performance decreases if 
organics reduction is optimized), then this would have to be taken into 
account in establishing a floor (or floors). (Optimized controls for 
both types of HAPS would not be MACT in any case, since the standards 
would not be mutually achievable.) The Senate Report indicates that in 
such a circumstance, EPA is to optimize the part of the standard 
providing the most environmental protection. S. Rep. No. 228, 101st 
Cong. 1st sess. 168. It should be emphasized, however, that ``the fact 
that no plant has been shown to be able to meet all of the limitations 
does not demonstrate that all the limitations are not achievable''. 
Chemical Manufacturers Association v. EPA, 885 F. 2d at 264 (upholding 
technology-based standards based on best performance for each pollutant 
by different plants, where at least one plant met each of the 
limitations but no single plant met all of them).
    All available data for HWCs indicate that there is no technical 
problem achieving the floor levels for each HAP or HAP metal group 
simultaneously, using the MACT floor technology. In the case of metals 
and PM, the characteristics of the MACT floor technology associated 
with the hardest-to-meet floor (e.g., the fabric filter with lowest 
air-to-cloth ratio) would define the MACT floor technology for purposes 
of determining achievability of floors and for purposes of costing out 
the impact of the standards. Existing data show that approximately 9 
percent of existing hazardous waste incinerators, approximately 8 
percent of hazardous waste-burning cement kilns, and approximately 25 
percent of hazardous waste-burning LWAKs are already achieving the 
proposed floor standards for all HAPs.
    Finally, EPA notes that the HAP-by-HAP or HAP group approach to 
establishing MACT floor levels is not unique to this rule. For example, 
the Agency has adopted it for the NESHAP for the secondary lead source 
category (60 FR 32589 (June 23, 1995)) and proposed the same approach 
for municipal waste combustors (59 FR 48198 (September 20, 1994)).
    As discussed above, EPA has the authority to establish MACT floors 
on a HAP group by HAP group basis and has done so in this case. In 
doing so, EPA will ensure that such floors, taken as a whole, are 
reasonably achievable for facilities subject to the MACT standards.

VI. Selection of Beyond-the-Floor Levels for Existing Sources

    As discussed in Section V above, the MACT floor defines the minimum 
level of emission control for existing sources, regardless of cost or 
other considerations. The process of considering emissions levels more 
stringent than the MACT floor for existing sources is called a 
``beyond-the-floor'' (BTF) analysis and involves consideration of 
certain additional factors, including cost, any non-air quality health 
and environmental impacts and energy requirements, technologies 
currently in use within these industry sectors, and also other more 
efficient and appropriate technologies that have been demonstrated and 
are available on the market (e.g., carbon bed for dioxin/furan 
control).
    Because there are virtually unlimited BTF emissions levels that the 
Agency could consider, the Agency used several criteria in this 
proposal to identify when to examine a particular beyond-the-floor 
emissions level in detail, and also whether to propose a MACT standard 
based on the beyond-the-floor emissions levels for existing sources.
    The primary factor is the cost-effectiveness of setting MACT 
standards based upon a more efficient technology than the MACT floor 
technology(ies). If the Agency's economic analysis suggested that BTF 
levels could be cost-effectively achieved (particularly if significant 
health benefits would result from a lower emission level), then an 
applicable BTF emission level control technology was identified to 
achieve that level. The associated costs were then weighed along with 
the other criteria. Dioxin/furans is an example

[[Page 17369]]

where the Agency considered a BTF level because a beyond-the-floor 
emission level can be achieved in a cost-effective manner, achieving, 
in addition, significant non-air quality environmental benefits.

VII. Selection of MACT for New Sources

    For new sources, the standards for a source category (or sub-
category) cannot be less stringent than the emission control that is 
achieved in practice by the best-controlled similar source. See 
Sec. 112(d)(3). The following discussion summarizes the methodology 
used by the Agency in developing today's proposed emissions standards 
for new HWC sources.
    The approach used to identify MACT for new sources parallels in 
most ways the approach used to determine the MACT floor for existing 
sources. For each HAP, the Agency identified the technology associated 
with the single best performing source (for each source category). The 
Agency used this best performing technology then looked at all 
facilities operating the control technology, and determined the 
achievable emission levels that represent ``the emission control that 
is achieved in practice by the best controlled similar source'' by 
using the maximum value achieved by properly-operated technology 
(adjusted upwards by a statistically derived variability factor). For 
further details, see the technical background documents \13\ supporting 
today's proposal.
---------------------------------------------------------------------------

    \13\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
---------------------------------------------------------------------------

    Since MACT for new sources is to reflect optimized achievable 
performance and is not necessarily limited to performance levels 
currently achieved, the Agency also considered several other factors in 
selecting the MACT new emissions limit. These factors included: (1) 
Comparisons to other emissions standards which may indicate that a 
technology is demonstrated and its level of performance (e.g., proposed 
municipal waste combustors and medical waste incinerators regulations 
and the European Union waste incineration standards); and (2) test 
condition emissions variability.
    As mentioned earlier, the Agency believes that it is appropriate to 
compare the proposed emissions standards for new sources to other 
existing or recently proposed standards applicable to hazardous waste 
combustors or similar devices as a type of ``reality check'' that we 
are developing the most rigorous emissions limits for new sources based 
upon the best technologies available today.
    The extracted data and data plots are presented in the background 
document \14\ located in the docket.
---------------------------------------------------------------------------

    \14\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
---------------------------------------------------------------------------

VIII. RCRA Decision Process

    It is EPA's intention to eliminate duplicative or potentially 
duplicative regulation wherever possible. In this section, we discuss: 
(1) The RCRA mandate to ensure protection of human health and the 
environment and how that mandate relates to the CAA technology-based 
MACT standards; (2) how, for RCRA purposes, we evaluated the 
protectiveness of the proposed MACT standards; (3) how, for RCRA 
purposes, the Agency intends to continue its policies with respect to 
site-specific risk assessments and permitting so that, in appropriate 
situations, additional RCRA permit conditions can be developed as 
necessary to protect human health and the environment; and (4) how 
waste minimization opportunities may be considered at individual 
facilities during the permitting process.

A. RCRA and CAA Mandates To Protect Human Health and the Environment

    The Agency is proposing emission standards for HWCs under joint 
authority of the Clean Air Act Amendments of 1990 and the Resource 
Conservation and Recovery Act (RCRA). As noted earlier, section 3004(a) 
of RCRA requires the Agency to promulgate standards for hazardous waste 
treatment, storage, and disposal facilities as necessary to protect 
human health and the environment. The standards for incinerators 
generally rest on this authority. In addition, Sec. 3004(q) requires 
the Agency to promulgate standards as necessary to protect human health 
and the environment specifically for facilities that burn hazardous 
waste fuels (e.g., cement and light-weight aggregate kilns). Using RCRA 
authority, the Agency has historically established emission (and other) 
standards for HWCs that are either entirely risk-based (e.g., site-
specific standards for metals under the BIF rule), or are technology-
based but determined by a generic risk assessment to be protective 
(e.g., the DRE standard for incinerators and BIFs).
    The MACT standards proposed today implement the technology-based 
regime of CAA Sec. 112. There is, however, a residual risk component to 
air toxics standards. Section 112(f) of the Clean Air Act requires the 
Agency to impose, within eight years after promulgation of the 
technology-based standards promulgated under Sec. 112(d) (i.e., the 
authority for today's proposed standards), additional controls if 
needed to protect public health with an ample margin of safety or to 
prevent adverse environmental effect. (Cost, energy, and other relevant 
factors must be considered in determining whether regulation is 
appropriate in the case of environmental effects.)
    As noted earlier, EPA's express intent is to avoid regulatory 
duplication. RCRA Sec. 1006 directs that EPA ``integrate all provisions 
of [RCRA] for purposes of administration and enforcement and * * * 
avoid duplication, to the maximum extent possible, with the appropriate 
provisions of the Clean Air Act * * *.'' The overall thrust of the 
proposed rule is to have the CAA standards supplant independent RCRA 
standards wherever possible (i.e., to have the CAA standards, wherever 
possible, also serve to satisfy the RCRA mandate so that additional 
RCRA regulation is unnecessary).
    Under RCRA, EPA must promulgate standards ``as may be necessary to 
protect human health and the environment.'' RCRA Sec. 3004(a) and (q). 
Technology-based standards developed under CAA Sec. 112 do not 
automatically satisfy this requirement, but may do so in fact. See 59 
FR at 29776 (June 6, 1994) and 60 FR at 32593 (June 23, 1995) (RCRA 
regulation of secondary lead smelter emissions unnecessary at this time 
given stringency of technology-based standard and pendency of 
Sec. 112(f) determination). If the MACT standards, as a factual matter, 
are sufficiently protective to also satisfy the RCRA mandate, then no 
independent RCRA standards are required. Conversely, if MACT standards 
are inadequate, the RCRA authorities would have to be used to fill the 
gap.
    It should be noted that this RCRA risk evaluation can inform the 
MACT decision process as well. For example, the RCRA risk evaluations 
indicate the potential for significant risk via indirect pathways from 
dioxins and furans originating in today's baseline air emissions for 
HWCs. EPA is explicitly authorized to consider non-air environmental 
impacts (such as exposure to HAPS which, after emission, enter into the 
food chain and are eventually consumed by humans and other biota) in 
determining whether to adopt standards more stringent than the MACT 
floor. Thus, EPA can consider benefits from curbing these

[[Page 17370]]

indirect exposures as part of its beyond-the-floor determinations.
    As discussed below, the Agency has conducted an evaluation, for the 
purposes of satisfying the RCRA statutory mandates, of the degree of 
protection afforded by the MACT standards being proposed today. 
However, the Agency's current RCRA evaluation is not intended to have 
any bearing on what we may or may not determine is necessary in several 
years to satisfy the Sec. 112(f) provisions.

B. Evaluation of Protectiveness

    To determine whether the MACT standards are consistent with the 
Agency's mandate under RCRA to establish standards for hazardous waste 
management facilities and to issue permits that are protective of human 
health and the environment, the Agency conducted two types of analyses 
to assess the extent to which potential risks from current hazardous 
waste combustion emissions would be reduced through implementation of 
MACT standards.
    The first of these analyses was designed to assess the potential 
risks to individuals living near hazardous waste combustion facilities 
and to nearby aquatic ecosystems. The procedures used in this analysis 
are discussed in detail in the background document contained in the 
docket for today's proposal.15 The results are summarized in Part 
Four of today's notice, ``Rationale for Selecting Proposed Standards''.
---------------------------------------------------------------------------

    \15\ ``Risk Assessment Support to the Development of Technical 
Standards for Emissions from Combustion Units Burning Hazardous 
Wastes: Background Information Document,'' February 20, 1996.
---------------------------------------------------------------------------

    The second analysis of potential risk reduction was a more 
qualitative evaluation of risks at the national level for those two 
constituents (dioxins and mercury) which the Agency believes pose 
significant health risks at the national level and which are found at 
significant concentrations in hazardous waste combustor emissions. The 
results of this analysis are presented in Section Seven, ``Regulatory 
and Administrative Requirements'', as part of the discussion of 
potential costs and benefits required under Executive Order 12866.
1. Individual Risk Analysis
    The Agency assessed potential risks to individuals from both direct 
inhalation of emissions (after dispersion in the ambient air) and 
indirect exposure to emissions through deposition onto soils and 
vegetation and subsequent uptake through the food chain. The analysis 
focussed primarily on dioxins and related compounds since these have 
been of major concern to the Agency from a risk perspective and because 
there is enough information about the properties of these constituents 
to allow for a quantitative analysis. The individual risk analysis did 
also include risks from inhalation of metals, hydrogen chloride, and 
chlorine (Cl2).
    The Agency conducted an evaluation of risks from metals through 
indirect exposure routes. With the exception of mercury, most of the 
metals are not expected to accumulate significantly in the food chain, 
and the risks from other indirect exposure routes (such as deposition 
on soil and incidental ingestion of the soil) are not projected to be 
significant, even with conservative assumptions.
    With respect to mercury, the Agency suspects that there may be 
significant individual risks near hazardous waste combustion 
facilities, primarily through deposition, erosion to surface waters, 
and accumulation in fish which are then consumed. However, the current 
state of knowledge concerning the behavior of mercury in the 
environment does not allow for a meaningful quantitative risk 
assessment of emission sources which is precise enough to support 
regulatory decisions at the national level. Specifically, there is 
insufficient information with respect to speciation of the mercury into 
various forms in emissions and with respect to the deposition and 
cycling of mercury species in the environment to conduct a defensible 
national quantitative assessment of mercury deposition, erosion to 
surface waters, and bioaccumulation in fish. The Agency solicits 
comment and information on the issue of the risks posed by mercury 
emissions from hazardous waste combustion facilities.
    The Agency also considered potential risks from emissions of non-
dioxin semi-volatile organics that are products of incomplete 
combustion (PICs). However, the Agency was not able to conduct an 
appropriate analysis for several reasons. First, the limited emissions 
data now available to the Agency on non-dioxin PICs are not 
sufficiently reliable to conduct an adequate assessment of risk. 
Second, there is not a universally accepted set of parameter values for 
some non-dioxin PICs with which to assess potential exposures (e.g., 
the use of octanol-water partition coefficients (Kow) to predict 
bioaccumulation versus the use of empirical data and the extent to 
which bioaccumulation of compounds such as phthalates and polycyclic 
aromatic hydrocarbons (PAHs) occurs in domestic animals). The Agency 
solicits comment on these issues and, in particular, requests data on 
bioaccumulation of PAHs, phthalates, and other non-dioxin PICs in farm 
animals used for food production and in other mammals and birds. The 
Agency also intends to obtain a better set of data relating to the non-
dioxin PIC emissions from hazardous waste combustion facilities.
2. Individual Risks From Dioxins
    In order to evaluate potential risks from dioxins to individuals 
living near hazardous waste combustion facilities, the Agency selected 
eleven example facility locations, consisting of areas in which five 
actual cement kilns, four incinerators, and two lightweight aggregate 
kilns are located. The example facility locations represent a variety 
of environmental settings and facility characteristics. The purpose of 
using example facilities was to incorporate as much realism as possible 
into the Agency's risk assessment and to reduce the reliance on 
hypothetical, conservative assumptions about either location or source 
type characteristics. Site-specific characteristics considered in the 
analysis include meteorological conditions, topography, and land use as 
well as stack height and gas flow rates. However, the stack gas 
concentrations used in the modeling of the example facilities were 
derived from national emissions data. Therefore, while the example 
facility analyses are useful for providing information to evaluate 
national standards on a generic basis, they are not site-specific 
assessments of any individual facility and cannot be regarded as such.
    The Agency has identified a number of indirect exposure pathways 
which are most likely to present significant risks. These include: 
consumption of locally-produced meat, eggs, and dairy products and 
consumption of fish from local waterways. Contamination of food occurs 
from deposition of toxic emissions onto plants and soil with subsequent 
ingestion by farm animals or, in the case of fish contamination, from 
deposition directly into water bodies or onto soil and runoff into 
surface waters with subsequent uptake in fish.
    In assessing risks to the more highly exposed individuals, the 
Agency assumed that certain segments of the population subsisted in 
part on home-produced foods or fish obtained from nearby lakes or 
streams. In addition, the Agency assumed that these individuals were 
exposed in the farming and fishing areas most affected by the example 
facilities' emissions. In its analysis of the eleven example 
facilities, the

[[Page 17371]]

Agency attempted to identify the actual location of farms and water 
bodies where subsistence activities might be expected to occur. For 
dioxins, the highest exposures are expected to occur for individuals 
whose diets include significant amounts of home-produced meat and eggs 
or locally caught fish. Individuals likely to have high exposures 
include subsistence farmers that raise beef cattle, dairy cows, or 
chickens along with their families as well as subsistence fishers and 
recreational anglers and their families.
    In evaluating individual risks, the Agency projected both ``high 
end'' and ``central tendency'' estimates of risks to the individuals of 
concern in the analysis. The central tendency estimates were derived by 
setting all emission rates, fate and transport parameters, and exposure 
assumptions at central tendency values, as described in the risk 
assessment background document. To derive high end risk estimates, the 
Agency set the emission levels at the 90th percentile of the 
distribution of available dioxin concentrations and, for most exposure 
scenarios, set one exposure parameter to a high end value while keeping 
all other parameters at central tendency values. For purposes of 
evaluating the protectiveness of the standards, the Agency used a 
target risk level of 10-5 for the high end individual risk, which is 
consistent with the approach taken in the 1991 BIF rule.
3. Uncertainties in the Individual Dioxin Risk Estimates
    Much of the information used to derive the individual risk 
estimates for dioxins was taken from the Agency's draft Dioxin 
Reassessment documents \16\ \17\ \18\. Those documents discuss in 
considerable detail a number of the uncertainties associated with both 
the cancer slope factor (the dose-response descriptor) and the many 
parameters used in the exposure assessment. Some of these uncertainties 
are also discussed in the risk assessment background document for 
today's proposal.
---------------------------------------------------------------------------

    \16\ ``Health Assessment Document for 2,3,7,8-
Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds Volume I 
and II'', Office of Research and Development, June 1994.
    \17\ ``Health Assessment Document for 2,3,7,8-
Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds Volume 
III'', Office of Research and Development, August 1994.
    \18\ ``Estimating Exposure to Dioxin-Like Compounds Volume I, 
II, and III'', Office of Research and Development, June 1994.
---------------------------------------------------------------------------

    In addition, there have been a large number of public comments on 
the Dioxin Reassessment, which the Agency is now considering. If the 
Agency decides to revise its assessment of either the toxicity or 
exposure associated with dioxins prior to the final promulgation of 
this rule, those revisions will be considered in the development of the 
final rule.
    The Agency is also conducting an external peer review of its risk 
analysis supporting today's proposal. The results of this peer review, 
which are expected during the comment period, will be available in the 
public record for this rule and will be considered in developing the 
final rule.
4. Qualitative Assessments of National Risks
    While the individual risk assessment discussed above provides a 
quantitative measure of the protectiveness of the proposed MACT 
standard, there are other ways of evaluating potential impacts of 
reducing emissions of hazardous constituents. One approach taken by the 
Agency is to describe to the extent practicable what is known about the 
national extent of risks from constituents such as dioxins and mercury. 
To put that information in context with respect to this rule, the 
relative contribution of hazardous waste combustion to other known air 
releases of these constituents to the environment is then presented. 
The Agency recognizes that it is not appropriate to quantitatively 
correlate emissions with risk on a national scale; nevertheless, this 
type of information is useful for qualitatively evaluating the 
potential impact of the proposed MACT rule.

C. Use of Site-Specific Risk Assessments Under RCRA

    As part of the Agency's Hazardous Waste Minimization and Combustion 
Strategy, EPA currently has a national RCRA policy of strongly 
recommending to all federal and state RCRA permit writers that, under 
the omnibus permit provisions of RCRA Sec. 3005(c)(3), site-specific 
risk assessments be performed as part of the RCRA permitting process if 
necessary to protect human health and the environment. Regions and 
authorized states have been implementing this national policy since 
mid-1993 under the aegis of the omnibus and other applicable 
authorities.
    The Combustion Strategy announced this policy encouraging site-
specific risk assessments as part of the overall effort to ensure that, 
under appropriate legal authorities, all RCRA combustion permits being 
issued are sufficiently protective. Specifically, these site-specific 
risk assessments were intended to address potential concerns about a 
suite of hazardous air pollutants, among them dioxins, furans, metals, 
and non-dioxin PICs, during the time it took for the Agency to upgrade 
the technical standards for hazardous waste incinerators, boilers, and 
industrial furnaces. This proposal is the first rulemaking that the 
Agency has issued in the upgrading effort.
    The question has arisen as to the status of the Agency's current 
policy with respect to site-specific risk assessments, particularly 
with respect to the HAPs for which standards are being proposed today 
as well as for other non-dioxin PICs. As noted above, the Agency has 
conducted a risk evaluation under RCRA of the degree of protection 
afforded by the proposed MACT standards for the HAPs addressed in 
today's rule. However, with respect to mercury and non-dioxin PICs, the 
Agency does not at this time have sufficient reliable data to be able 
to assess, on a national basis, the magnitude of the risks that can 
routinely be expected from burning hazardous waste in HWCs. Although 
the Agency has plans to obtain extensive and detailed PIC emissions 
data from hazardous waste combustors in the coming months, it may be 
some time before the Agency is in a proper position to make any type of 
regulatory and policy judgment about the need, if any, for additional 
national standards for these toxic organics. Indeed, at several sites, 
the levels of some non-dioxin PICs have not previously been shown to be 
of concern, at least to the extent that site-specific testing revealed 
their presence and to the extent evaluated in site-specific risk 
assessments.
    The Agency is continuing its policy of recommending that, if 
necessary to protect human health and the environment, site-specific 
risk assessments be conducted as part of RCRA permitting for all 
hazardous waste combustors (incinerators, boilers, and industrial 
furnaces alike) until national standards for HAPs of concern are in 
place. We expect that, in most situations prior to actual 
implementation of facility measures to appropriately control the HAPs 
addressed in this rule, the EPA regional and authorized state 
permitting officials will find there is a necessity to conduct site-
specific risk assessments prior to final permit determinations. We also 
note that the remaining uncertainties about the risks from non-dioxin 
PICs and mercury would likely bear upon implementation of the national 
policy. However, small on-site facilities are not likely to present the 
same level of potential risk as other facilities. This industry segment 
may not warrant site specific risk assessments with the same frequency 
as the large on-site or

[[Page 17372]]

commercial facilities. Among the factors that the regions and states 
should consider in their evaluation of the necessity for a site-
specific risk assessment are: (1) The current level of HAPs being 
emitted by a facility, particularly in comparison to the MACT standards 
being proposed and in comparison to the emissions assumptions and 
exposure scenarios used in the RCRA risk evaluation of the proposed 
MACT standards (detailed in the Background Document); (2) whether the 
facility is exceeding the proposed HAP standards, particularly for 
dioxins/furans and mercury, what immediate measures could be instituted 
to reduce those emissions; (3) the scope of waste minimization efforts 
at the facility with respect to the HAPs of concern and the status of 
implementation of any facility waste minimization plan; (4) particular 
site-specific considerations such as proximity to receptors, unique 
dispersion patterns, etc.; (5) the PICs most likely to be found and 
those most likely to pose significant risk; (6) the presence or absence 
of other sources of HAPs in sufficient proximity as to exert a 
significant influence on interpretation of a facility-specific risk 
assessment; (7) the presence or absence of significant ecological 
considerations, including for example high background levels of a 
particular contaminant or proximity of a particularly sensitive 
ecological area; and (8) the volume and types of wastes being burned. 
This list is by no means exhaustive, but is meant only to suggest 
significant factors that have thus far been identified. Others may be 
equally or more important.
    Continuation of the site-specific risk assessment policy rests 
primarily on the RCRA requirement to ensure that all permits are 
protective of human health and the environment. Until the Agency is in 
a position to determine, on a national basis, whether additional 
standards are needed to address toxic emissions, we anticipate this 
policy will remain in effect. EPA's intention is to make that 
determination, if sufficient data is in hand, by the time of the final 
rule, now scheduled for issuance in December 1996. In that respect, we 
emphasize the importance of the submission of detailed data on non-
dioxin PICs from commenters.
    In the meantime, the omnibus provision in Sec. 3005(c)(3) provides 
the regions and authorized states with the proper site-by-site 
authority to ensure that these risk assessments are completed as part 
of the permitting process. Other RCRA statutory and regulatory 
provisions may apply as well. Furthermore, we encourage individual 
facilities to work with their local communities in designing these risk 
assessments and in carrying out the testing and analysis, so that the 
confidence of local communities is maximized.
    In addition, EPA strongly urges companies to explore waste 
minimization opportunities as a means to reduce risks from combustion 
emissions, particularly with respect to the HAPs of concern. Nearly 
every state provides free pollution prevention/waste minimization 
technical assistance. Further information on how to obtain this 
assistance can be furnished by state permitting agencies or by 
contacting the National Pollution Prevention Roundtable at (202) 466-
7272. Other sources of information include Enviro$ense, an electronic 
library on pollution prevention, technical assistance, and 
environmental compliance. Access is via a system operator (703) 908-
2007, via modem at (703) 908-2092, or via Internet at http://
wastenot.inel.gov/enviro-sense.

PART FOUR: RATIONALE FOR SELECTING THE PROPOSED STANDARDS

    This part describes the Agency's rationale for today's proposed 
standards and other options under consideration.

I. Selection of Source Categories and Pollutants

A. Selection of Sources and Source Categories

    The Agency is proposing emissions standards for three source 
categories: hazardous waste incinerators, hazardous waste-burning 
cement kilns, and hazardous waste-burning lightweight aggregate kilns. 
The Agency is not proposing to regulate emissions from CKs (in this 
notice) or LWAKs that do not burn hazardous waste.
    In this section, we discuss the Agency's analysis of subdividing 
incinerators by size (i.e., small and large sources) and subdividing 
cement kilns by process type (i.e., wet and dry). We also discuss the 
scope of the MACT standards for cement kilns, and the existing RCRA 
standards that control emissions of HAPs from equipment leaks and tanks 
which are used to manage hazardous waste.
1. Consideration of Subdividing Incinerators by Size
    Section 112(d) allows the Administrator to distinguish among 
classes, types, and sizes of sources within a source category in 
establishing MACT floor levels. Given that the size of incinerators, as 
measured by gas flow rate in actual cubic feet per minute (acfm), 
varies substantially (i.e., from 1,000 acfm to 180,000 acfm), the 
Agency considered subdividing incinerators by size.
    The basis for distinguishing between small and large incinerators 
as well as the preliminary estimates of the resultant floor levels for 
each category are presented in the docket and summarized below. The 
Agency is not proposing separate standards (at the floor) 19 for 
incinerators because: (1) the types and concentrations of uncontrolled 
HAP emissions are similar for large and small incinerators; (2) the 
same types of emission control devices are applicable to both small and 
large incinerators; and (3) the floor levels would be generally 
unchanged 20 (several floor levels would decrease somewhat), with 
the exception that the LVM standard for large incinerators would 
increase by more than a factor of four. We believe that the higher LVM 
floor level for large incinerators would not be appropriate given that 
approximately 80 percent of incinerators already are meeting the LVM 
floor without subdividing.
---------------------------------------------------------------------------

    \19\ Note that we discuss in Part Four, Section III in the text 
whether beyond-the-floor standards for D/F, Hg, and PM (as currently 
proposed for all incinerators) are appropriate for small 
incinerators.
    \20\ And therefore, a level of complexity would be added to the 
rule without substantial benefit.
---------------------------------------------------------------------------

    The Agency invites comment on its determination that subdividing 
incinerators by size would not be warranted. We also invite comment on 
whether subdividing incinerators by other classifications (e.g., 
commercial versus on-site units) would be appropriate for establishing 
MACT floor levels. Commenters should provide data and information on, 
in particular: (1) how the types and concentrations of uncontrolled HAP 
emissions are different for the suggested categorization of sources; 
(2) whether and why MACT emission control technology would not be 
applicable to a category of sources; and (3) other appropriate factors.
    To investigate the effect on MACT floor levels of subdividing 
incinerators by size, the Agency identified a gas flow rate of 23,127 
acfm as a reasonable and appropriate demarcation between small and 
large incinerators. This value was determined using a slope analysis 
approach whereby gas flow rates for each source (for which the Agency 
had data) were plotted in ascending order. The Agency chose the point 
at which the slope markedly changed as the point of demarcation between 
small and large incinerators. Approximately 57 percent of incinerators 
for which we have gas flow rate data would be classified as small using 
this approach.

[[Page 17373]]

    Projected MACT floor levels for small and large incinerators are 
compared to floor levels for combined incinerators (i.e., without 
subdividing) in the table below:

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Small incinerators                     Large incinerators                                               
                                     ------------------------------------------------------------------------------   Floor levels for all incinerators 
                                                   Floor level                            Floor level                             combined              
--------------------------------------------------------------------------------------------------------------------------------------------------------
D/F (ng/dscm).......................  0.2 TEQ or <400  deg.F...............  0.2 TEQ or <400  deg.F...............  0.2 TEQ or <400  deg.F.             
PM (mg/dscm)........................  180..................................  180..................................  180                                 
Hg (g/dscm)................  110..................................  130..................................  130                                 
SVM (g/dscm)...............  230..................................  270..................................  270                                 
LVM (g/dscm)...............  160..................................  880..................................  210                                 
HCl + Cl2 (ppmv)....................  280..................................  260..................................  280                                 
CO (ppmv)...........................  100..................................  100..................................  100                                 
HC (ppmv)...........................  12...................................  12...................................  12                                  
--------------------------------------------------------------------------------------------------------------------------------------------------------

2. Consideration of Subdividing Cement Kilns by Manufacturing Process
    The Agency also considered whether to subdivide the cement kiln 
source category into wet and dry process kilns given that these types 
of kilns are designed and operated differently. (See discussion in Part 
Two, Section II.) MACT floor levels for wet and dry kilns are compared 
to floor levels for combined cement kilns (i.e., without subdividing) 
in the table below:

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Wet process kilns                      Dry process kilns                                                
              Pollutant              ------------------------------------------------------------------------------  Floor levels for all kilns combined
                                                   Floor level                            Floor level                                                   
--------------------------------------------------------------------------------------------------------------------------------------------------------
D/F (ng/dscm).......................  0.2 TEQ or 418  deg.F................  0.2 TEQ or 547  deg.F................  0.2 TEQ or 418  deg.F.              
PM (mg/dscm)........................  69...................................  69...................................  69                                  
Hg (g/dscm)................  83...................................  150..................................  130                                 
SVM (g/dscm)...............  870..................................  57...................................  57                                  
LVM (g/dscm)...............  220..................................  49...................................  130                                 
HCl + Cl2 (ppmv)....................  460..................................  340..................................  640                                 
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Subdividing cement kilns by process type would result in a mix of 
impacts with varying degrees of significance. For wet kilns, the main 
impact would be an increase in the SVM floor from 57 to 870 g/
dscm. The mercury floor, on the other hand, would drop from 130 to 83 
g/dscm. The remainder of the floors would remain roughly the 
same. For dry cement kilns, the main impact would be that the LVM floor 
drops from 130 to 49 g/dscm. The dioxin/furan floor would 
change by allowing a higher APCD temperature--547  deg.F rather than 
418  deg.F.
    The Agency is not proposing separate standards for wet and dry 
process kilns because: (1) The types and concentrations of uncontrolled 
HAP emissions are similar for both types of kilns; (2) the same types 
of emission control devices are applicable to both types of kilns; (3) 
for dry process kilns, the LVM floor level would drop to an extremely 
low level that may be difficult for many kilns to achieve because of 
the presence of these metals in raw materials; and (4) for wet kilns, 
the SVM floor would increase to 870 g/dscm, a level much 
higher than the industry can achieve.21 There may also be other 
factors that should be considered, and the Agency invites comment on 
those in addition to the factors noted above.
---------------------------------------------------------------------------

    \21\ See letter from Craig Campbell, CKRC, to James Berlow, 
USEPA, undated but received February 20, 1996. We note that, 
although the Agency is proposing a SVM standard of 57 g/
dscm, we invite comment on an alternative (and potentially 
preferable) approach to identify MACT floor technology which would 
result in a floor-based standard of 160 g/dscm. See Part 
Four, Section IV in the text. Because we identified the alternative 
approach late in the rule development process, we are inviting 
comment on the higher standard rather than proposing it.
---------------------------------------------------------------------------

    We note that the cement industry has asserted that it is not 
feasible to use a FF on wet kilns in cold climates because the ``high 
moisture content of the gas will clog the fabric with cement-like dust 
and ice.'' 22 This is not consistent with the Agency's 
understanding. Although wet kilns located in cold climates that operate 
at low flue gas temperatures (e.g., 350-400  deg.F) in order to 
minimize formation of D/F and improve performance of activated carbon 
injection systems may be required to improve insulation or take other 
measures to minimize cold spots in the baghouse to limit corrosion, we 
believe that appropriate measures can be readily taken. The Agency is 
aware of two wet kilns that currently operate fabric filters in cold 
climates (Thomaston, Maine, and Dundee, Michigan) at flue gas 
temperatures below 400  deg.F. \23\ In addition, a wet kiln 
burning hazardous waste in Paulding, Ohio, is currently upgrading its 
PM control system to replace an ESP with a FF.
---------------------------------------------------------------------------

    \22\ See letter from Micheal O'Bannon, EOP Group, to Elliot 
Laws, USEPA, dated February 14, 1996, p. 3 of Attachment.
    \23\ See USEPA, ``Draft Technical Support Document For HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February, 1996, for further information.
---------------------------------------------------------------------------

    The Agency invites comment on the appropriate criteria to be used 
and upon its determination that subdividing cement kilns by process 
type is not warranted. Commenters should provide data and information 
on, in particular: (1) Whether the types and concentrations of 
uncontrolled HAP emissions are different for wet and dry kilns; (2) 
whether and why MACT emission control technology(ies) would not be 
applicable to a wet or dry kiln; and (3) other appropriate factors.
3. Scope of the MACT Standards for Cement Kilns
    The proposed NESHAP for cement kilns addresses only exhaust 
combustion gas emissions from main stack(s), bypass stack(s), and 
fugitive combustion emissions (e.g., leaks from kiln seals). The cement 
kiln standards would not apply to process or fugitive emissions that 
are not affected

[[Page 17374]]

by burning hazardous waste (such as emissions from raw material 
processing or clinker cooler emissions). 24
---------------------------------------------------------------------------

    \24\ Today's proposal applies only to those kilns that burn or 
process hazardous waste irrespective of the purpose of burning or 
processing. The term ``burn'' means burning for energy recovery or 
destruction, or processing as an ingredient. The Agency is 
developing a NESHAP for cement kilns that do not process hazardous 
waste in a separate rulemaking. That NESHAP will also regulate those 
hazardous waste-burning cement kiln process and fugitive emissions 
that would not be subject to today's rule (i.e., emission sources 
other than the main or by-pass stack).
---------------------------------------------------------------------------

4. Current RCRA Controls on Equipment Leaks and Tanks
    We note that the Agency has promulgated air emission standards 
regulating fugitive emissions from equipment leaks (e.g., pumps, 
compressors, valves) and tanks which are used to manage hazardous 
waste. Accordingly, these devices are not addressed by today's 
proposal. (Tanks and equipment leaks from HW management activities at 
HWCs are regulated under RCRA standards. See, e.g., 40 CFR Parts 264 
and 265, Subparts AA, BB, and CC. These controls are expected to be 
consistent with MACT and are not being reevaluated here.)

B. Selection of Pollutants

    As noted earlier, section 112(b) of the Clean Air Act contains a 
list of 189 hazardous air pollutants for which the Administrator must 
promulgate regulations establishing emissions standards for designated 
major and area sources. The list of 189 HAPs is comprised of metallic, 
organic, and inorganic compounds.
    Hazardous waste incinerators and hazardous waste-burning cement 
kilns and LWAKs emit many of the listed HAPs. Data available to the 
Agency indicate that metal HAP emissions include antimony, arsenic, 
beryllium, cadmium, chromium, lead, mercury, nickel, and selenium 
compounds. Organic HAPs emitted include chlorinated dioxin and furan, 
benzene, carbon disulfide, chloroform, chloromethane, 
hexachlorobenzene, methylene chloride, naphthalene, phenol, toluene, 
and xylene. Hydrochloric acid and chlorine gas are prevalent inorganic 
compounds found in stack emissions because of high chlorine content of 
many hazardous wastes.
    Today, the Agency is proposing eight emissions standards for 
individual HAPs, group of HAPs, or HAP surrogates. These emission 
standards cover dioxin/furan, mercury, particulate matter, semivolatile 
HAP metals (lead and cadmium), low-volatile HAP metals (antimony, 
arsenic, beryllium, and chromium), carbon monoxide, hydrocarbons, and 
total chlorides. The following discussion presents the Agency's 
rationale for proposing NESHAPs for these individual HAPs, group of 
HAPs, or HAP surrogates.
1. Toxic Metals
    In developing today's proposed rule, the Agency considered 14 toxic 
metals that may pose a hazard to human health and the environment when 
they are components of emissions from hazardous waste combustion 
sources. Section 112(b) of the Act contains a list of 11 metal HAPs: 
antimony, arsenic, beryllium, cadmium, chromium, cobalt, lead, 
manganese, mercury, nickel, and selenium. The list of hazardous 
constituents under RCRA 25 specifies three additional metals: 
barium, silver, and thallium. Five of these metals (or their compounds) 
are known or suspected carcinogens: arsenic, beryllium, cadmium, 
hexavalent chromium, and nickel.
---------------------------------------------------------------------------

    \25\ The list of hazardous constituents is contained in appendix 
VIII of Part 261. Cobalt and manganese are not hazardous 
constituents.
---------------------------------------------------------------------------

    To develop an implementable approach for controlling the metal HAP 
emission levels, the Agency grouped metal HAPs by their relative 
volatility and is proposing an emissions limit for the each volatility 
group (i.e., the sum of emissions from the metals in the group cannot 
exceed the limit). We selected the following three groups: (1) A high-
volatile group comprised of only mercury, (2) a semivolatile group 
comprised of lead and cadmium, and (3) a low-volatile group consisting 
of antimony, arsenic, beryllium, and chromium. The Agency's proposal 
not to include the remaining seven toxic metals in these volatility 
groupings is discussed later in this section.
    Our data indicate that mercury is generally in the vapor form in 
and downstream of the combustion chamber, including at the air 
pollution control device (APCD). Thus, the level of emissions is a 
function of the feedrate of mercury and the use of APCDs that can 
control Hg in the vapor form (e.g., carbon injection, wet scrubbers for 
some control of soluble HgCl). The semivolatile group metals typically 
vaporize at combustion temperatures, then condense onto fine 
particulate before entering the APCD. Thus, emissions of semivolatile 
metals are a function not only of the feedrate of the metal, but also 
of the efficiency of the particulate matter (PM) control device. Low-
volatile metals are less apt to vaporize at combustion temperatures and 
therefore partition primarily to the bottom ash, residue, or clinker 
(in the case of cement kilns) or adsorb onto large, easy-to-control 
particles in the combustion gas. Thus, low-volatile metal emissions are 
more strongly related to the operation of the PM APCD than to the 
feedrate.26
---------------------------------------------------------------------------

    \26\  Although, at a given PM emission rate at a source, 
emissions of LMV will be affected by LVM feedrate.
---------------------------------------------------------------------------

    We note that the dynamics associated with the fate of metals in a 
combustion device are much more complex than presented here. Numerous 
factors impact metals' behavior such as the presence of chlorine 
(higher metal volatility associated with metal chlorides than metal 
oxides), combustion conditions within the device (e.g., temperature 
profile), inter-metal relationships, physical and chemical form the 
metal exhibits when introduced to the device (e.g., valence state and 
solid versus liquid), type and efficiency of the particulate control 
device, and differences in the design and operation of sources (e.g., 
cement kiln dust recycling rate). See the technical background document 
supporting today's proposal for more details.27
---------------------------------------------------------------------------

    \27\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume VII: Miscellaneous Technical Issues'', February 
1996.
---------------------------------------------------------------------------

    Setting an emission level for a number of grouped metals has 
several advantages and disadvantages. One advantage is that fewer 
individual standards are involved, which helps implementability. 
Moreover, grouping allows a facility more flexibility in complying with 
an emissions standard based on facility-specific characteristics (e.g., 
special characteristic waste streams) and operation requirements (e.g., 
reduced spiking of numerous metals). On the other hand, a disadvantage 
of a group emission limit is that it potentially allows higher 
emissions of the more toxic metals within a group (than if an 
individual metal limit were established).28
---------------------------------------------------------------------------

    \28\ We note that, for the risk assessment used to determine if 
RCRA concerns would be adequately addressed by the proposed MACT 
standards, we assumed that each metal in a volatility was emitted in 
turn at the emission limit for that volatility group.
---------------------------------------------------------------------------

    The Agency is proposing not to regulate directly emissions of the 
remaining four metal HAPs (i.e., cobalt, manganese, nickel, and 
selenium).29 The

[[Page 17375]]

Agency's rationale is based upon a combination of factors: (1) 
Inadequate emissions data for Co, Mg, Ni, and Se; and (2) relatively 
low toxicity of Co and Mn. The Agency specifically requests comment on 
whether these four metals would be adequately controlled under the MACT 
standards that would be provided by today's proposal.
---------------------------------------------------------------------------

    \29\ The Agency acknowledges that three metals (barium, silver 
and thallium), currently regulated by the BIF rule, would not be 
regulated under this MACT proposal. EPA notes that these three 
metals are not HAPs. The Agency believes that the combination of the 
proposed particulate and metals standards would adequately control 
emissions of these three metals.
---------------------------------------------------------------------------

    The Agency is aware of two other approaches to group toxic metals. 
First, the European Union has established three groupings to control 
metal emissions from hazardous waste incineration units. One ``group'' 
includes only mercury, a second group consists of cadmium and thallium, 
and the third group includes antimony, arsenic, chromium, cobalt, 
copper, lead, manganese, nickel, tin, and vanadium. Section VII of this 
Part summarizes the European Union emission standards.
    A rulemaking petition 30 submitted to the Agency by the Cement 
Kiln Recycling Coalition (CKRC) contained a report 31 (appendix D 
of the petition) prepared by a technical advisory board to the CKRC. 
Their analysis of stack emissions and cement kiln dust data suggests 
three volatility groupings based on metal volatility demonstrated in 
cement kilns. The groupings are: (1) Volatile metals including mercury 
and thallium; (2) semivolatile metals consisting of antimony, cadmium, 
lead, and selenium; and (3) low-volatile metals comprising barium, 
beryllium, chromium, arsenic, nickel, manganese, and silver. See the 
technical background document for further discussion on grouping metals 
by volatility.32 The Agency requests comments on the 
appropriateness of grouping metals by volatility and requests 
supporting information and data on the appropriate composition of metal 
volatility groups (i.e., for the metals discussed above).
---------------------------------------------------------------------------

    \30\ CKRC's rulemaking petition proposes to establish new 
technology-based combustion emissions standards and was submitted to 
EPA on January 18, 1994. CKRC's petition consists of four basic 
components. First, the stringency of current BIF Rule toxic metal 
limits should be increased by factors of 5 to 10 and applied to all 
combustion devices (i.e., both BIFs and incinerators). Second, new 
regulatory efforts for dioxin/furan standards should focus on a 
toxic equivalency approach (TEQ) rather than on a total congener 
approach. Third, the implementation of the new metals and dioxin/
furan standards should be applied uniformly to all types of 
hazardous waste combustors (HWCs) and imposed at the same time. 
Finally, EPA should conduct a rulemaking on indirect exposure risk 
assessments before requiring their use. CKRC's petition has been 
placed in the docket supporting today's proposal.
    \31\ ``Scientific Advisory Board on Cement Kiln Recycling 
(Process Technology Workgroup), Evaluation of the Origin, Emissions 
and Control of Organic and Metal Compounds From Cement Kilns Co-
Fired With Hazardous Wastes,'' June 8, 1993.
    \32\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume VII: Miscellaneous Technical Issues,'' February 
1996.
---------------------------------------------------------------------------

2. Toxic Organic Compounds
    Burning hazardous waste that contains toxic organic compounds under 
poor combustion conditions can result in substantial emissions of HAPs 
originally present in the waste as well as other compounds, due to the 
partial but incomplete combustion of the constituents in the waste 
(known as products of incomplete combustion, or PICs). PICs can be 
unburned organic compounds that were present in the waste, thermal 
decomposition products resulting from organic constituents in the 
waste, or compounds synthesized during or immediately after combustion. 
The quantity of toxic organic compounds emitted depends on such factors 
as the combustion conditions under which the waste is burned (including 
time, temperature, and turbulence), the concentrations of the toxic 
compounds in the waste, and the waste firing rate.
    Since the majority of the 189 enumerated HAPs are organics, the 
Agency has concluded (for today's proposal) that establishing 
individual emission limits for each of the organic HAP compounds 
emitted from these combustion sources would be impractical and not 
implementable. Measuring each compound would be very costly and would 
pose unreasonable compliance and monitoring burden on the regulated 
community while achieving little, if any, emission reduction from the 
approach presented in today's proposal. In addition, EPA and state 
compliance oversight and enforcement efforts would also be unreasonably 
costly without concurrent benefits. Also, the Agency does not have 
adequate emissions data to support development of individual organic 
emission limits 33 at this time. Therefore, the Agency is 
proposing a multi-faceted approach to control the toxic organic HAPs to 
be addressed under Sec. 112: (1) Emissions limits for dioxin and furan 
on a toxicity equivalents (TEQ) basis; (2) limits on flue gas 
concentrations of hydrocarbons (HC) as a HAP surrogate; (3) limits on 
flue gas concentrations of carbon monoxide (CO) also as a HAP 
surrogate; and (4) emission limits for particulate matter (PM) to 
control adsorbed semivolatile organic HAPs (see separate discussion on 
PM below).
---------------------------------------------------------------------------

    \33\ The number of organic HAPs measured at each facility varies 
widely with some facilities reporting measurements for a large 
number of HAPs while other facilities measuring only a few HAPs.
---------------------------------------------------------------------------

    First, given the high toxicity of some dioxin and furan congeners 
and the fact that standards ensuring good operating conditions alone 
(i.e., temperature at the inlet of the APCD) will not always control 
emissions of dioxin/furans
(D/F), the Agency has determined that proposing an emission standard 
specifically for D/F is a necessary component to the multi-faceted 
approach for toxic organics emissions control. The D/F standard 
proposed today is based on TEQ (Toxicity Equivalents).34 TEQ is a 
method for assessing the risks associated with exposures to complex 
mixtures of chlorinated dibenzo-p-dioxin and dibenzofurans (CDDs and 
CDFs). The method relates the toxicity of the 209 structurally related 
chemical pollutants to the toxicity of 2,3,7,8-tetrachlorodibenzo-p-
dioxin (2,3,7,8-TCDD).
---------------------------------------------------------------------------

    \34\ The TEQ approach used for today's proposal is the I-TEQ/89 
approach defined in USEPA, ``Interim Procedure for Estimating Risks 
Associated With Exposures to Mixtures of Chlorinated Dibenzo-p-
Dioxin and -Dibenzofurans (CDDs and CDFs) and 1989 Update,'' March 
1989. For a discussion of establishing D/F limits based on TEQ 
versus total congeners, see USEPA, ``Combustion Emissions Technical 
Resource Document (CETRED),'' May 1994, pp. 4-21.
---------------------------------------------------------------------------

    Second, the Agency is proposing to use carbon monoxide (CO) and 
hydrocarbons (HC) as surrogates to control emissions of non-D/F organic 
HAPs. We note that limiting CO and HC emissions to levels ensuring good 
combustion conditions would also help minimize D/F precursors. CO and 
HC emissions are both recognized indicators of combustion intensity and 
completeness. Low CO flue gas levels are indicative of a combustion 
device operating at high combustion efficiency (56 FR at 7149-54). 
Operating at high combustion efficiency helps ensure minimum emissions 
of unburned (or incompletely burned) organics. However, limiting CO may 
not by itself absolutely minimize PIC emissions. This is because PICs 
can result from small pockets within the combustion zone where adequate 
time, temperature, turbulence, and oxygen have not been provided to 
completely oxidize these organics.35 As combustion becomes less 
efficient or less complete, at some point, the emissions of total 
organics (measured as HC) will increase. A

[[Page 17376]]

portion of the HC emission is comprised of organic HAPs. Thus, CO 
levels provide an indication of the potential for organic HAP emissions 
and CO limits are therefore proposed as a measure to help prevent these 
emissions. HC limits are proposed to document actual emissions of 
organic HAPs.36
---------------------------------------------------------------------------

    \35\ We note that there are emissions data indicating that even 
though CO levels are below 100 ppmv, HC emissions can exceed 5 ppmv 
(measured as propane with a heated sampling system), the upper HC 
level that is generally representative of operating under good 
combustion conditions. See 56 FR 7154, note 26 (February 21, 1991), 
and Energy and Environmental Research Corporation, ``Surrogate 
Evaluation of Thermal Treatment Systems,'' Draft Report dated 
October 17, 1994, Figure 2-1.
    \36\ We note that virtually all HWCs are already equipped with a 
CO monitor because of RCRA requirements. In addition, several 
incinerators, cement kilns and lightweight aggregate kilns are also 
equipped with a HC monitor because of RCRA or state requirements or 
voluntary initiative.
---------------------------------------------------------------------------

    Notwithstanding today's proposal to establish MACT standards for 
both CO and HC emissions for HWIs and LWAKs (CKs would be required to 
comply with either a CO or HC standard for technical reasons discussed 
in Section IV below), the Agency invites comment on whether standards 
for both CO and HC (coupled with the D/F and PM standards to also 
control organic HAPs) are unnecessarily redundant. Commenters should 
provide data and information on how either CO or HC alone (but in 
conjunction with
D/F and PM standards) would ensure proper control of organic HAPs. In 
particular, commenters should address the fact that the Agency's 
database indicates that HC levels can exceed good combustion condition 
levels when CO levels are below 100 ppmv (thus suggesting that controls 
on both CO and HC are needed). In addition, commenters should address 
how the MACT standards proposed today for HC would or could ensure that 
sources operate under good combustion conditions and thus minimize 
emissions of organic HAPs.
    If based on review of comments and further analysis the Agency 
determines that standards for both CO and HC are not warranted, we 
would consider, among other potential options, the following 
alternative regulatory approaches: (1) Give each source the option of 
complying with either the CO or HC standard (as proposed today for 
technical reasons for by-pass duct gas for cement kilns); or (2) 
establish a national standard for either CO or HC, but not both (the 
Agency would determine which parameter is more appropriate and 
establish a standard for that parameter). The Agency invites comment on 
these alternative regulatory approaches or others that would ensure 
proper control of organic HAP emissions.
3. Hydrochloric Acid (HCl) and Chlorine (Cl2)
    Both hydrochloric acid and chlorine are designated HAPs that are 
present in HWC emissions. However, the test method used to determine 
HCl and Cl2 emissions (BIF methods 0050, 0051, and 9057, commonly 
referred to as ``Method 26A'') 37 may not be able to distinguish 
between HCl and Cl2 in all situations.38 Therefore, EPA 
proposes combining the two HAPs into a single HCl and Cl2 
standard. We believe this is appropriate because emissions of both of 
these HAPs can be controlled by limiting feedrate of chlorine in 
hazardous waste and wet scrubbing.39
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    \37\ We note that owners and operators of cement kilns have 
argued that this method provides measurements that are biased high 
because metallic salts penetrate the filter and the chloride is 
incorrectly reported as HCl. EPA has considered this concern and 
continues to believe that metallic salts do not significantly bias 
the results. Nonetheless, we invite comment on this issue. If, in 
fact, metallic salts can bias the results, we invite comment 
particularly on how or whether the proposed MACT standards could be 
adjusted given the inflated emissions database, and how compliance 
with an adjusted standard could be demonstrated.
    \38\ In the presence of other halogens (e.g., fluorine and 
bromine) that are often constituents of hazardous waste, fossil 
fuels or kiln raw materials, EPA is concerned that reactions can 
occur in the impinger solutions used by the stack sampling method 
that cause a portion of the Cl2 to be reported as HCl. Thus, 
the HCl levels could be biased high, and the Cl2 levels could 
be biased low. Nonetheless, the method does continue to give an 
accurate determination of combined HCl and Cl2 levels in the 
presence of other halogens.
    \39\ We also note that, for purposes of determining whether the 
proposed MACT standard would satisfy RCRA concerns, we evaluated the 
level of protection that would be provided assuming (conservatively) 
that 10 percent of the HCl/Cl2 standard would be emitted as the 
more toxic Cl2.
---------------------------------------------------------------------------

4. Particulate Matter (PM)
    EPA is proposing to use particulate matter (PM) as a surrogate for 
non-D/F organic HAPs (that are adsorbed onto the PM) and for the metal 
HAPs which are not specified in the metals standards (i.e., Co, Mn, Ni, 
and Se).40 More than 40 semivolatile organic HAPs can be adsorbed 
onto PM and can, thus, be controlled by a MACT standard for PM.41 
The metal HAPs that are not directly controlled by the MACT standards 
for metals can also be controlled (at least partially) by a PM 
standard. The low volatility metals are likely to be entrained in 
larger particulates and the semivolatile metals are likely to be 
condensed onto small particulates.
---------------------------------------------------------------------------

    \40\ We note that PM 10 is a criteria pollutant under the Clean 
Air Act. PM can also have adverse effects on human health even if 
toxics are not adsorbed on the PM. Although EPA cannot control PM in 
and by itself under Sec. 112(d) (it must be a surrogate for HAP 
control), EPA may consider reductions in criteria pollutants in 
assessing cost-effectiveness of MACT controls. See S. Rep. No. 228, 
101st Congress, 1st Session, p. 172.
    \41\ See memo from Larry Gonzalez, EPA, to the docket for this 
rule (F-96-RCSP-FFFFF), entitled ``Semi-volatile Organic HAPs that 
Can Be Adsorbed onto PM'', dated February 22, 1996.
---------------------------------------------------------------------------

    The Agency notes that we are proposing to use PM also as a 
compliance parameter to ensure compliance with the SVM, LVM, and D/F 
standards. As discussed in Part V, Section II, of the preamble, a site-
specific PM operating limit would be established as a surrogate for the 
PM control device collection efficiency. Given that we are also 
proposing a PM MACT emission standard, the site-specific operating 
limit for PM could not exceed the PM standard.

C. Applicability of the Standards Under Special Circumstances

    In this section, we discuss the applicability of the proposed MACT 
standards under the following circumstances: (1) When a regulated metal 
or chlorine is not present in the hazardous waste at detectable levels; 
(2) when the source temporarily ceases hazardous waste burning; and (3) 
when the source terminates hazardous waste burning.
1. Nondetect Levels of Metals or Chlorine in All Feedstreams
    If no feedstreams to a HWC (e.g., on-site incinerator) contain 
detectable levels of Hg, SVM, LVM, or chlorine, the source would not be 
subject to the emission standard associated with the metal or chlorine 
(e.g., if no feedstreams contain detectable levels of chlorine, the 
HCl/Cl2 standard would be waived). In addition, performance 
testing, monitoring, notification, and recordkeeping requirements 
ancillary to the waived standard would also be waived. We believe that 
this waiver is appropriate because the source would be incompliance 
with the emission standard by default if it was not feeding the metal 
or chlorine.
    To be eligible for the waiver, the source must develop and 
implement a feedstream sampling and analysis plan to document that no 
feedstream contains detectable levels of the metal or chlorine (for 
which a waiver is claimed).
    The Agency invites comment on whether it is necessary to specify 
minimum detection levels (or to take other measures) to ensure that 
appropriate analytical procedures are used to document levels of metal 
or chlorine in feedstreams.
2. Nondetect Levels of Metals or Chlorine in the Hazardous Waste Feed
    The proposed MACT standards for mercury, SVM, LVM, or chlorine 
would apply even if these constituents are not present at detectable 
levels in the

[[Page 17377]]

hazardous waste. This issue is relevant for cement kilns and light-
weight kilns because, if these sources were not burning hazardous 
waste, the proposed MACT standards would not apply. Cement kilns (CKs) 
that do not burn hazardous waste would be subject to separate MACT 
standards that the Agency is developing for those sources, and light-
weight aggregate kilns (LWAKs) that do not burn hazardous waste would 
not be subject to any MACT standards.
    It could be argued that a CK or LWAK that burns hazardous waste 
with nondetect levels of Hg, SVM, LVM, or chlorine is not burning 
hazardous waste with respect to that metal or the HCl/Cl2 
standard. Accordingly, regulation should revert to any applicable MACT 
standard for the source when not burning hazardous waste. The Agency 
rejects this argument, however. A source cannot be subject to 
regulation under two MACT source categories. Further, such an approach 
would be extremely difficult to implement and enforce for CKs given 
that compliance procedures would be different for the two source 
categories.
3. Sources That Temporarily Cease Burning Hazardous Waste
    Sources that temporarily cease burning hazardous waste would remain 
subject to today's proposed standards. Similar to the discussion above, 
such sources could argue that in the interim when hazardous waste is 
not burned, MACT regulation should revert to the MACT standards 
applicable to CKs or LWAKs that do not burn hazardous waste.
    The Agency rejects this argument as well and for the same reasons 
discussed above: a source cannot be intermittently subject to MACT 
regulation under two source categories, and implementation and 
enforcement would be extremely complicated. See the discussion below 
regarding how to define temporary interruptions in waste burning versus 
termination of waste burning.
4. Sources That Terminate Hazardous Waste Burning
    A source that terminates hazardous waste burning would no longer be 
subject to today's proposed rules. A source has terminated hazardous 
waste burning when it: (1) ceases burning hazardous waste (i.e., 
hazardous waste is not fed and hazardous waste does not remain in the 
combustion chamber); and (2) stops complying with the proposed 
standards and begins complying with other applicable MACT standards 
(i.e., cement kilns must comply with the MACT standards, when 
promulgated, for kilns that do not burn hazardous waste). In addition, 
today's rule would require sources that terminate hazardous waste 
burning to notify the Administrator in writing within 5 days of the 
termination.
    Such sources could begin burning hazardous waste again under the 
following conditions: (1) The source must comply with the MACT 
standards applicable to new sources; (2) the source must submit a 
notification of compliance with the standards (based on a comprehensive 
performance test); and (3) prior to submitting the notification of 
compliance, the source cannot burn hazardous waste for more than a 
total of 720 hours, and hazardous waste may be burned only for purposes 
of emissions pretesting (i.e., in preparation for the comprehensive 
performance test) or comprehensive performance testing.
    We are taking this position regarding termination of waste burning 
to avoid the implementation and enforcement complications that could 
result if a source could claim that it was not subject to the proposed 
regulations during those periods of time that it was not burning 
hazardous waste. Without these requirements, a source could vacillate 
at will between being regulated and unregulated (or for CKs, between 
being subject to regulation as a hazardous waste-burning kiln versus a 
non-hazardous waste-burning kiln). We invite comment on whether these 
requirements are reasonable and appropriate to address the Agency's 
implementation and enforcement concerns.

II. Selection of Format for the Proposed Standards

A. Format of the Standard

    When EPA regulates a source, it must determine on a case-by-case 
basis what format the standards are. This section explains the reasons 
why EPA chose the format it did for this specific source category. Due 
to differing situations in other cases, other formats may be chosen for 
other source categories.
1. Units
    EPA investigated four formats for use in expressing today's 
proposed standards: mass-based emissions; calculated mass-based 
emissions; percent reduction; and concentration-based. The Agency 
ultimately selected concentration-based standards for the reasons 
discussed below.
    The mass-based approach would set a limit of mass emissions per 
unit time, i.e., kg/hr, lb/hr, etc. This approach was rejected because 
it is inherently incompatible with technology based standards for 
several reasons. First, a mass-based standard does not assure good 
control at small facilities. Small facilities have lower flow rates, 
would be allowed higher concentration of emissions, and thus could meet 
a standard with no or minimal technological control. Also, it produces 
an undue burden on larger facilities in that they would have to install 
controls and small facilities would not. One potential consequence is 
that it would cause an incentive for more small facilities, causing an 
increase in emissions nationally. For these reasons, this option was 
not chosen.
    An alternate to the mass-based approach is the calculated mass-
based approach. This would involve EPA determining some appropriately 
low level of metals and chlorine feed, multiplying that by a system 
removal efficiency factor, and issuing the result as a mass-based 
limit. One concern with this approach is EPA does not know what 
feedrate would be appropriate. Any feedrate could be construed as 
arbitrary. Also, the approach would result in a mass-based limit which 
does not address concerns described in the preceding paragraph. It also 
does not address how to set the other standards: CO, HC, PM, and 
dioxin/furans. For these reasons, this option was not chosen.
    A third approach is to set the standards based on a specified 
percent reduction. This comports well with a technology-based approach 
because it deals directly with determining what technology performs 
most efficiently. However, there are problems with this approach. 
First, it is difficult to determine where the percent reduction should 
be applied: feed to stack, across the APCD train, or across a specific 
control device. Use of feed to stack percent reductions present a 
difficulty due to the measurement variability of feed samples and stack 
emissions. APCD train or device specific percent reductions would be 
difficult to implement. Facilities are not configured to sample inlet 
emissions to the APCD train or to a specific APCD. Thus, facilities 
would have to be reconfigured to allow inlet sampling. Stack sampling 
would be required at both the outlet and, possibly, multiple inlet 
points. This would significantly increase the testing burden. In 
addition, implementation of any approach based on percent reduction 
would involve substantial and expensive monitoring of operating 
parameters to ensure that the specified percent reduction occurs during 
operation. For these reasons, this approach was not chosen.

[[Page 17378]]

    The approach that was chosen for these source categories is to set 
concentration-based standards. This approach is consistent with how EPA 
has historically based air emission standards. It favorably addresses 
the problems of the other options. However, it does allow larger 
facilities to emit higher mass emissions of HAPs. But mass-based levels 
would result in higher emissions nationally by encouraging more smaller 
facilities (see previous paragraph). This tradeoff, having higher mass 
emissions at larger facilities but lower emissions nationally, was 
considered acceptable for this proposal. Concentration based approaches 
are also easier to implement and do not necessarily rely on the setting 
of operating limits. For this reason, concentration-based standards are 
regarded as preferable to the other options, and was chosen on that 
basis.
    It is possible that other units could be chosen for other source 
categories. As explained in the introductory paragraph this is 
consistent because other units might be more appropriate for other 
source categories.
2. Correction to 7 Percent Oxygen and 20 deg. C
    All standards are corrected to 7 percent oxygen and 20 deg. C. This 
is because the data EPA used to derive the standards were corrected in 
this manner. This is also consistent with the correction used for BIFs, 
hazardous waste incinerators, MWCs, and MWIs.
3. Significant Figures and Rounding
    All standards proposed here are expressed to two significant 
figures.
    For the purposes of rounding, we propose to require the use of ASTM 
procedure E-29-90 or its successor. This procedure is the American 
standard for rounding. Rounding shall be avoided prior to rounding for 
the reported result.

B. Averaging Periods

    Averaging periods are the time periods over which emissions or 
feedstream and operating parameters are set. These periods require 
consideration because of the inherent variability associated with the 
operation of complying (i.e., properly designed and operated) MACT 
devices. As noted above, facilities normally operate within certain 
limits but do have emissions above and below these normal levels due to 
the natural variability associated with the operation of a facility. 
EPA must account for this variability when promulgating technology-
based standards. See, e.g., FMC Corp. v. Train, 538 F.2d 973, 986 (4th 
Cir. 1976). If EPA were to establish a ``not-to-be-exceeded'' limit, 
that limit would invariably be higher than if the limit were expressed 
as an average emission level. That would tend to encourage higher 
emitting, but low variability devices since they could meet the not-to-
exceed standard.
    For instance, say EPA is considering establishing a standard on: an 
instantaneous basis; a one hour average; and a 12-hour average. Also, 
assume that the complying MACT facility has average emissions of 5 and 
short-term perturbations as high as 300. In this case equally stringent 
emissions levels could be: 300 on an instantaneous basis; on the order 
of 10 for an hourly average; or closer to 5 for the 12-hour average. If 
the limit were established at 300 on an instantaneous basis, this could 
significantly favor a facility that has high perturbations less than 
300, but average emissions of 250 (assuming the facility with average 
emissions of 250 could meet the instantaneous limit, 300, with fewer 
controls.) This facility would emit 50 times more of that HAP than a 
facility operating at an emission average of 5, but would still comply 
with the standard. To address the problem of setting limits on an 
instantaneous basis, emissions and feedstream and operating limits are 
established on the average with specified averaging periods.
1. Manual Methods
    The MACT standards for HWCs (except those for HC and CO) were based 
on the average of data from three test runs during which emissions were 
measured by manual methods. EPA thus proposes that compliance be based 
on the average of three manual methods test runs to be consistent with 
data used to establish the standards. Chemical Waste Management v. EPA, 
976 F.2d 2, 34 (D.C. Cir. 1992) (Noting that this is an inherently 
reasonable approach and is consistent with the standard approach for 
compliance under the Part 63 MACT standards.)
    The standard could be set in such a way as to require all three 
runs to be less than the standard. Such a standard would be derived by 
choosing the highest data point from three manual test runs and would 
result in an emission level higher than those proposed. The ``not-to-
be-exceeded'' approach was considered problematic for reasons just 
described, so averaging was chosen.
    Manual methods sample facility exhaust emissions for a period of 
time. The minimum length of time required to sample is specified 
indirectly by the manual method in the form of collection or gas flow 
specifications. The results of the manual method test are reported as 
an average over the sampling period. Therefore for manual method test 
runs, the averaging period is the sampling period over which the sample 
was collected.
    EPA proposes no specific averaging period here for manual method 
test runs, with one caveat discussed below. Instead EPA proposes to 
rely on the minimum sampling volumes or collected sample (whichever the 
method requires) specified by the manual methods. EPA invites comment 
on whether minimum sampling periods for manual methods should be 
specified directly.
    EPA is proposing a three hour minimum sampling time for method 
0023A. Three hours is also the minimum sampling period stated in method 
23 to Part 60, appendix A. EPA is proposing a minimum sampling time in 
order to ensure that each D/F run samples long enough to obtain 
adequate samples of the various congeners to determine compliance with 
the TEQ standard. This issue is important here because there is an 
inconsistency between air rules and RCRA rules regarding how to treat 
nondetected congeners when calculating the TEQ.
    The document which defines the TEQ calculation, ``Interim 
Procedures for Estimating Risks Associated with Exposures to Mixtures 
of Chlorinated Dibenzo-p-Dioxins (CDDs and CDFs) and 1989 Update'' 
(EPA/625/3-89/016, March 1989), uses in its examples the assumption 
that all non-detects are zero. Also, Method 23 of Part 60 Appendix A, 
the method used by air programs for determining total D/F congeners, 
similarly states in Section 9, titled Calculations:

    Any PCDD's or PCDF's that are reported as nondetected (below the 
MDL) shall be counted as zero for the purpose of calculating the 
total concentration of PCDD's and PCDF's in the sample.

Therefore, many assume that nondetects are zero for the purposes of 
calculating site specific TEQs.
    Unfortunately, RCRA programs in most instances use the nondetect 
value, not zero, in the calculation of the TEQ. (See BIF method 23 
found in Part 266, Appendix IX, section 3.4.) Since this rule would be 
promulgated under both RCRA and CAA authority, this issue needs to be 
resolved.
    The Agency believes a facility will have to measure for 20 minutes 
per run using SW-846 method 0023a to obtain enough sample to be useful 
for the TEQ calculation. This leads EPA to believe that enough sample 
will be collected during a three hour run to assure that

[[Page 17379]]

nondetected congeners are indeed not present. If a source complies with 
the minimum sampling period and still has non-detects, then EPA 
proposes allowing non-detects to be assumed to be zero.
    This would also apply to other methods which have passed the Method 
301 validation procedures and EPA has agreed are acceptable. In the 
case of other methods, the facility would assume that non-detects are 
zero if the method accumulates the same amount or more sample than 
Method 0023A would in a three hour run. If a source chooses not to 
comply with the three hour minimum, EPA would mandate that non-detected 
congeners be assumed to be present at the detection level for the 
purposes of the TEQ calculation.
    EPA specifically invites comments on the selection of the proposed 
minimum sampling time for the D/F method and the assumed concentration 
of nondetected congeners in the calculation of the TEQ.
2. Continuous Emissions Monitoring Systems (CEMS)
    EPA is proposing to require the use of five CEMS--CO, HC, O2, 
Hg, and PM--and to allow the use of CEMS for SVM, LVM, HCl, and 
Cl2. Presently, for cement kilns and LWAKs, continuous emission 
monitoring of O2 and CO (or HC) is required under the BIF rule (40 
CFR 266.103(c)(1)(v)). Emission limits and their associated averaging 
period must be established for all of these pollutants (except for 
O2) in keeping with the nature of compliance with a CEMS. (The 
O2 CEMS is used to continuously correct the CEMS readings for the 
other pollutants to 7 percent O2. There is no emission limit 
specific to O2.) Hourly rolling average emissions data are 
available to establish emission limits for CO and HC on an hourly-
rolling average.
    Only manual method stack emissions data, however, are available to 
establish appropriate emission limits and averaging periods for the 
other standards: Hg, PM,42 SVM, LVM, and HCl and Cl2. This 
presents a unique issue for the Agency to resolve since, in most cases, 
EPA promulgates CEMS standards by collecting CEMS emissions data from 
facilities run under ``normal'' conditions. The Agency would use this 
CEMS data to calculate a statistically based CEMS emission standard, 
assuming some confidence interval and number of annual exceedances. 
Since no ``normal'' CEMS data exists, but worst-case manual test data 
from trial burns and compliance tests does, an alternate approach must 
be developed to derive a CEMS emission standard an its associated 
averaging period.
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    \42\ Note that the PM CEM is also used as an operating parameter 
for PM APCD efficiency and that additional averaging periods apply 
during normal operation. See Part Five, Section II.C.7. titled 
``Particulate Matter'' for more information.
---------------------------------------------------------------------------

    a. Approach to Establishing Averaging Periods for Hg, PM,43 
SVM, LVM, HCl and Cl2 CEMS. One important issue concerning the 
data is that it was obtained from trials burn and compliance test 
results (similar to the comprehensive performance test, described in 
section III of Part Five). These are generally worst-case tests 
facilities used to establish operating limits under the BIF and 
Incinerator rules. Facilities must be in compliance with all standards 
at all times they are burning hazardous waste. Therefore, the emissions 
represented by this data are the highest emissions the facility could 
experience and be in compliance with the current BIF and incinerator 
rules. In other words, the emissions data represents a not-to-be-
exceeded emission level for the given facility.
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    \43\ Note that the PM CEM is also used as an operating parameter 
for PM APCD efficiency and that additional averaging periods apply 
during normal operation. See Part Five, Section II.C.7. titled 
``Particulate Matter'' for more information.
---------------------------------------------------------------------------

    Now, let us examine how a facility would comply with today's 
proposed emission standards if they were not to use a CEMS, but by 
performing a comprehensive performance test and complying with the 
standards using operating parameter limits. As a result of today's 
proposed rule and as was the case in the BIF and incinerator rules, EPA 
believes facilities will conduct a comprehensive performance test in 
the same way current trial burns and compliance tests are conducted. 
That is they will attempt to get the widest operating envelope possible 
by intentionally running the facility under conditions which will 
maximize emissions (by practices such as maximizing feed-rates, running 
control devices less effectively, etc.) and yet not exceed any 
applicable emission standards. Facilities will use the operating data 
from the comprehensive test to establish and continuously monitor 
operating limits for feedrate and device parameters. This defines the 
facility's operating envelope. During normal operation, owner/operators 
will operate in such a way that the facility is performing better than 
the operating limits established during the comprehensive performance 
test. Since exceedances of operating limits established during the 
comprehensive performance test are a de facto violation of the 
corresponding standard, this means that the emissions during normal 
operation will at all times be lower than those during the 
comprehensive test.
    When complying with today's proposed standards using a CEMS, it is 
important that facilities using a CEMS not be at a disadvantage 
relative to facilities using operating parameter limits. There are two 
ways a disadvantage could occur: when the emission standard is 
numerically less and/or the averaging period is shorter. In the case of 
manual stack tests, the averaging period is the stack sampling time. 
Therefore, the CEMS emission limit would be equal in stringency to the 
manual stack test limit if they both had the same numerical value and 
the CEMS averaging period were equal to the sampling period for the 
manual method.
    Also, EPA believes facilities have a number of advantages using 
CEMS. First, the assumptions to assure compliance are fewer and less 
conservative (direct measure of the standard is the top of the 
monitoring hierarchy; see section II.A. of Part Five.) CEMS are less 
intrusive on the facility than operating parameter limits. Most 
importantly, CEMS mean facilities need to monitor only one emissions 
parameter to assure compliance rather than multiple operating limits, 
often relevant to more than one standard.44
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    \44\ For example, an exceedance of an operating parameter limit 
used to ensure compliance with the dioxin, mercury, SVM, LVM, and 
HCl and Cl2 standards would be a violation of all those 
standards. If a CEM were used for one or more of these standards, a 
violation would only occur if the CEM limit were exceeded.
---------------------------------------------------------------------------

    In summary, regardless of whether CEMS or operating limits are 
used, both continually assure that the facility is meeting the 
standard(s) at all times. CEMS are an alternate, more direct, method of 
confirming a state of performance than are continuously monitored 
operating parameter limits established through a comprehensive test. A 
facility which complies with the standards in today's proposed rule 
would experience its highest emissions during a comprehensive 
performance test, when the facility establishes its operating envelope 
to ensure it is in compliance with the standards at all times. 
Therefore, a CEMS limit is equally stringent to a standard for a 
comprehensive performance test if it is numerically equal and has the 
same averaging period. For comprehensive performance tests, the 
averaging period is the sampling time for the manual method. Therefore, 
it is proposed that the CEMS standards be the same numerical limits 
established for manual method comprehensive performance tests with the 
averaging period equal to

[[Page 17380]]

the sampling period for three manual method test runs.
    b. Averaging Periods for CO and HC CEMS. As stated previously, the 
data used to derive today's proposed CO and HC standards proposed are 
not manual methods data, but continuous emissions data based on a one-
hour rolling average. To be consistent with the data used to derive the 
standards, it is proposed that the averaging periods for CO and HC CEMS 
standards remain one-hour.
    c. Averaging Periods for Other CEMS. Based on the discussion of 
subsection I above, EPA proposes the following CEMS averaging periods 
for CEMS. The numerical standard is the same as those proposed in 
sections III through V of this part.
    Three main assumptions were used in determining how long a facility 
would have to sample to achieve the minimum levels specified in the 
manual methods. They are assumptions for: sample flow rate; flue gas 
oxygen content; and the detection limit or specified sample collection 
specified in the method. For sample flow rate, EPA assumed a flow rate 
of 0.5 scfm because this is either what is directly stated as the flow 
rate in the methods or it is used by convention.
    The Agency also assumed that the oxygen concentration in the flue 
gas was 7 percent, the basis of today's standards. Oxygen 
concentrations in the flue gas can change greatly, but EPA believes 
that the derived sampling time is elastic relative to the assumed 
oxygen concentration. In other words, the sampling times would change 
roughly five to ten per cent over the range of oxygen concentrations 
experienced by HWCs. This is not significant relative to other 
assumptions made here, so a 7 percent oxygen concentration was assumed.
    Finally, each method specifies a minimum analytical detection limit 
or sample collection. We assumed that a test operator would collect 
three times what is prescribed in the method to account for facility 
variability, unknowns at a given site, etc. This is a conventional 
approach used by testing contractors. This will be referred to below as 
the ``collected sample.''
    There are other issues which need to be addressed as well. One CEMS 
can be used to comply with more than one standard and standards can 
vary from subcategory to subcategory. Therefore, EPA proposes that the 
sampling time used to derive the averaging period be the longest 
sampling time which relates to the CEM averaging period. For an 
example, see the discussion on the Hg and multi-metals CEM standards, 
below.
    Manual methods tests do not run on-the-hour, so an averaging 
periods with some fraction of an hour would result if rounding were not 
used. EPA believes it is reasonable and simpler to have integer value 
hourly averages. Since the direct measure of a standard at the stack is 
at the top of the monitoring hierarchy, a less conservative approach is 
warranted in this case, so EPA proposes that averaging periods for CEMS 
be rounded up to the nearest hour. (See section II.A. of Part Five for 
more information on the monitoring hierarchy.)
    Also, a resulting averaging period may be inappropriately short, 
i.e., less than one hour. In this case EPA would establish an averaging 
period of one-hour. This is reasonable since the averages for operating 
parameters to control average emissions are one-hour. (See section 
II.B.1. of Part Five for a discussion of averages for operating 
parameters.) Monitoring of a standard continuously at the stack is at 
the top of the monitoring hierarchy, while establishing operating 
parameter limits is at the bottom. It would be inconsistent if an 
averaging period for CEMS were less than those for operating parameter 
limits, so a one-hour average will be proposed in this case.
    For mercury (Hg) and multi-metal CEMS, it is proposed that the 
averaging period be ten hours. SW-846 method 0060 would be the manual 
method used to comply with these standards if a CEM were not used. 
Emission standards for these HAP categories vary greatly from HAP-to-
HAP and within a HAP, from subcategory-to-subcategory. But the proposed 
SVM standard for LWAKs results in the longest sample collection time. 
EPA believes that an LWAK will have to sample for approximately 200 
minutes per run to collect 15 g of sample to be in compliance 
with the LWAK SVM standard. Three runs of 200 minute duration is 600 
minutes, or ten hours.
    For the HCl and Cl2 standard, it is proposed that the CEMS 
averaging period be one hour. In this case, EPA has determined that a 
facility would have to sample less than ten minutes per run to collect 
the minimum amount, 300 g, of sample specified by the method. 
If three times this sampling time were used to establish the averaging 
time, it would result in one of roughly 30 minutes. This is 
unreasonable for a CEMS averaging period, so EPA is proposing that the 
averaging period be one hour.
    Finally, it is proposed that the PM CEMS averaging period be two 
hours. This is because a facility would have to sample for roughly 30 
minutes per run to collect the minimum amount, 30 mg, of particulate 
specified by the method. Three times this sampling time is 1.5 hours, 
so after rounding an averaging period of two hours is proposed.
    Table IV.2.1 summarizes the CEMS averaging period for the various 
CEMS emission standards.

           Table IV.2.1.--Averaging Periods for CEMS Standards          
------------------------------------------------------------------------
              HAP or standard                   CEMS averaging period   
------------------------------------------------------------------------
PM.........................................  2 hours.                   
Mercury (Hg)...............................  10 hours.                  
SVM........................................  10 hours.                  
LVM........................................  10 hours.                  
HCl and Cl2................................  1 hour.                    
CO.........................................  1 hour.                    
HC.........................................  1 hour.                    
------------------------------------------------------------------------

    d. All Averages are Rolling Averages. All CEMS averaging periods 
are on a rolling-basis. In other words, each time a sample is recorded, 
a new rolling average is calculated using the new sample and all 
previous samples obtained during the specified averaging period. If 
sample results are recorded every minute and the averaging period is 
one hour, then the most recent sample is averaged together with the 
results of the previous 59 samples to obtain the hourly rolling 
average. When there are not enough data to obtain a rolling average, 
one of two approaches would be used. We propose that for short-term 
interruptions of the rolling average that the rolling average ``pick-
up'' where it left off, i.e., consider the one-minute average 
immediately prior to the interruption to be the one minute average that 
occurred prior to the current one-minute average. For longer term 
interruptions, all available one minute averages would be averaged 
together until the time period since the start of the rolling average 
equals the averaging period for that parameter. Then there is enough 
data to perform the rolling average as usual, and the rolling average 
would continue as normal. For more information on the use of CEMS and 
the rolling average, see Part Five, Section II.C. ``Compliance 
Monitoring Requirements'' and the proposed regulations, Appendix J to 
Part 60.
3. Feedstream and Operating Limits
    Today, EPA is proposing specific monitoring requirements to ensure 
facilities are in compliance with the standards during normal 
operation. Some of these monitoring requirements require setting limits 
on feedstream or operating parameters. These limits will

[[Page 17381]]

be set on an average. Other limits would be instantaneous limits, such 
as those for fugitive process emissions.
    It is proposed that four averaging periods be used for feedstream 
and operating limits: twelve hour, one hour, ten minutes, and 
instantaneous. All averages would be calculated on a rolling-average 
basis with measurements taken every 15 seconds to obtain a one minute 
average. The one minute averages are used to obtain the twelve hour, 
one hour or ten minute rolling average. The use of one-minute averages, 
i.e., the average of the previous 15 second averages within that 
minute, is the current practice for HWCs. ``Instantaneous'' limits are 
just that, values not to be exceeded at any time. Averaging does not 
occur for ``instantaneous'' values. These definitions supersede 
requirements in the Part 63 general provisions, which are less 
stringent. Consult chapter 5, volume IV of the Technical Background 
Document for more information regarding EPA's choice of the time 
duration for averaging periods.
    For discussion on what operating limits EPA is proposing and what 
the averaging period will be for particular operating limits, see 
section II of Part Five of this preamble.

III. Incinerators: Basis and Level for the Proposed NESHAP Standards 
for New and Existing Sources

    Today's proposal would establish maximum achievable control 
technology (MACT) emission standards for dioxins/furans, mercury, 
semivolatile metals (cadmium and lead), low volatile metals (arsenic, 
beryllium, chromium and antimony), hydrochloric acid and chlorine 
(combined), particulate matter, carbon monoxide, and hydrocarbons from 
existing and new hazardous waste incinerators (HWIs). See proposed 
Sec. 63.1203. The following discussion addresses how MACT floor and 
beyond-the-floor (BTF) levels were established for each HAP, and EPA's 
rationale for the proposed standards. The Agency's overall procedural 
approach for MACT determinations has been discussed in Part Three, 
Sections V and VI for existing sources and in Section VII for new 
sources.
    To conduct the MACT floor analyses presented today, the Agency 
compiled available data from hazardous waste-burning incinerators: both 
commercial as well as on-site facilities. As discussed earlier, the 
vast majority of these data were generated during trial burns to 
demonstrate compliance with existing RCRA standards at 40 CFR Part 264, 
Subpart O. Therefore, the data were obtained under proper QA/QC 
procedures. These emissions data, however, represent worse-case 
emissions that cannot be exceeded (because limits on operating 
parameters are based on operations during the trial burn). As noted 
earlier, the Agency invites commenters to submit data that reflect more 
normal, day-to-day operations and emissions. This will enable the 
Agency, among other things, to be better able to distinguish among 
facilities that are now included in the expanded MACT floor pool but 
which, upon closer inspection and with better data, may not be actually 
employing the identified floor controls.

A. Summary of MACT Standards for Existing Incinerators

    This section summarizes EPA's proposed emission levels for existing 
incinerators for each HAP, HAP group, or HAP surrogate. The proposed 
emission standards for HWIs are presented in the table below:

   Table IV.3.A.1.--Proposed MACT Standards for Existing Incinerators   
------------------------------------------------------------------------
         HAP or HAP surrogate                Proposed standards \1\     
------------------------------------------------------------------------
Dioxin/furans........................  0.20 ng/dscm TEQ.                
Particulate Matter...................  0.030 gr/dscf.                   
                                       (69 mg/dscm).                    
Mercury..............................  50 g/dscm.              
SVM [Cd, Pb].........................  270 g/dscm.             
LVM [As, Be, Cr, Sb].................  210 g/dscm.             
HCl + Cl2............................  280 ppmv.                        
CO...................................  100 ppmv.                        
HC...................................  12 ppmv.                         
------------------------------------------------------------------------
\1\ All emission levels are corrected to 7 percent O2.                  

1. Dioxins and Furans (D/Fs)
    a. MACT Floor. The Agency's analysis of dioxin/furan (D/F) 
emissions from HWCs and other combustion devices (e.g., municipal waste 
combustors and medical waste incinerators) indicates that temperature 
of combustion gas at the inlet to the particulate matter (PM) control 
device can have a major effect on D/F emissions.45 D/F emissions 
generally decrease as the gas temperature of the PM control device 
decreases, and emissions are lowest when the gas temperature of the PM 
control device is below the optimum temperature window for D/F 
formation--450 to 650  deg.F.46 Given that incinerators are 
equipped with both wet and dry PM control devices that operate under a 
range of temperatures, the Agency is identifying a MACT floor for D/F 
based on temperature control at the inlet to the PM control device.
---------------------------------------------------------------------------

    \45\ USEPA, ``Draft Technical Support Document For HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
    \46\ For example, during compliance testing of a cement kiln, D/
F emissions exceeded 1.7 ng/dscm (TEQ) at a ESP temperature of 
435 deg. F.
---------------------------------------------------------------------------

    Incinerators emitting D/F at or below levels emitted by the median 
of the best performing 12 percent of incinerators have combustion gas 
temperatures below 400 deg. F. These best performing sources were 
equipped with venturi scrubbers to control PM. The gas temperature of 
the wet air pollution control system for one source was 163 deg. F; gas 
temperature data for the other best performing sources were not 
available. Although gas temperatures at a wet PM control device would 
normally be less than 200 deg. F, temperatures could be higher in the 
presence of acid gases such as HCl and SO2. Consequently, the 
Agency believes that it would be reasonable and appropriate to 
generalize that gas temperatures of wet PM control devices are less 
than 400 deg. F.
    The Agency evaluated D/F emissions from all incinerators that are 
equipped with wet PM control systems. Average D/F emissions for test 
conditions ranged from 0.01 ng/dscm (TEQ) to 39 ng/dscm (TEQ). D/F 
emissions were as high as 3.5 ng/dscm (TEQ) for incinerators that were 
not burning substantial levels of known D/F precursors or were not 
equipped with a waste heat boiler (WHB). (It is hypothesized that WHB-
equipped incinerators may have high (uncontrolled) D/F emissions 
because D/F may be formed on particulate attached to boiler tubes as 
combustion gases pass through the optimum temperature window (450-
650 deg. F) for D/F formation.) WHB-equipped incinerators using wet PM 
control devices had D/F emissions ranging from 0.4 to 8 ng/dscm (TEQ), 
and an incinerator equipped with a wet PM control device burning waste 
comprised of approximately 30 percent PCBs had D/F emissions of 39 ng/
dscm (TEQ).
    The Agency is consequently identifying temperature control to below 
400 deg. F at the PM control device as the MACT floor. Given that 
approximately 45 percent of test conditions in our database have 
average D/F emissions below 0.20 ng/dscm (TEQ), we believe that it is 
appropriate to express the floor as ``0.20 ng/dscm (TEQ), or 
temperature at the PM control device not to exceed 400 deg. F''. This 
would allow sources that operate at temperatures above 400 deg. F but 
that achieve the same D/F emissions as 45 percent of sources that 
operate below 400 deg. F to meet the standard without incurring the 
expense of

[[Page 17382]]

lowering the PM control device gas temperature.
    EPA estimates that 75 percent of incinerators are currently meeting 
the floor level. The annualized cost for the remaining incinerators to 
reduce D/F emissions to 0.20 ng/dscm (TEQ) or control gas temperature 
at the PM control device to below 400 deg. F would be $3.0 million. 
Achievement of the floor levels would reduce D/F TEQ emissions 
nationally by 35 g/yr.
    b. Beyond-the-Floor (BTF) Considerations. The Agency has identified 
activated carbon injection (CI) operated at gas temperatures less than 
400 deg. F as BTF control for D/F for incinerators.47 CI is 
currently used by a commercial hazardous waste incinerators to achieve 
emission levels routinely (based on quarterly stack testing) of less 
than 0.20 ng/dscm (TEQ). CI is also used to reduce D/F emissions from 
several municipal and medical waste incinerators (MWIs) in a similar 
manner.
---------------------------------------------------------------------------

    \47\ We note that incinerators using wet PM control systems 
would need to reheat the combustion gas before injecting the carbon. 
This is because CI is not efficient at D/F (or Hg) removal at gas 
temperatures below the dew point. Gas reheating in these situations 
was considered in estimating the cost of compliance with the 
proposed standards.
---------------------------------------------------------------------------

    CI has been demonstrated to be routinely effective at removing 
greater than 95 percent of D/F and some tests have demonstrated a 
removal efficiency exceeding 99 percent at gas temperatures of 400 deg. 
F or below.48 To determine a BTF emission level, the Agency 
considered the emission levels that could result from gas temperature 
control to less than 400 deg. F combined with CI.
---------------------------------------------------------------------------

    \48\ USEPA, ``Draft Technical Support Document For HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
---------------------------------------------------------------------------

    To estimate D/F emissions with temperature control combined with 
CI, the Agency considered the range of emissions from sources in the 
MACT floor database, as discussed above. Incinerators that are not 
equipped with a WHB and not burning high levels of D/F precursors (the 
vast majority of incinerators) could be expected to achieve D/F 
emissions of less than 3.5 ng/dscm (TEQ) with temperature control only. 
These sources could be expected to achieve D/F emissions of below 0.18 
ng/dscm (TEQ) when using CI assuming a fairly conservative removal 
efficiency of 95 percent.
    There are three sources in our database equipped with WHBs. One 
currently uses CI to achieve D/F emissions below 0.20 ng/dscm (TEQ) 
when controlling PM with an ESP operating below 400 deg. F. Another 
source had D/F emissions of 0.56 ng/dscm (TEQ) when controlling PM with 
a wet system. This source could be expected to achieve D/F emissions 
below 0.03 ng/dscm (TEQ) using CI at a removal efficiency of 95 
percent. The third WHB-equipped incinerator in our database had D/F 
emissions of 8.0 ng/dscm (TEQ) when controlling PM with a wet system. 
This source could be expected to achieve D/F emissions below 0.40 ng/
dscm using CI at a removal efficiency of 95 percent. We note, however, 
that the feed to this source during testing comprised approximately 10 
percent hexachlorophenol, a D/F precursor.
    Finally, one incinerator in the database that controlled PM with a 
wet system had D/F emissions of 39 ng/dscm (TEQ). This source could be 
expected to achieve D/F emissions below 2 ng/dscm (TEQ) when using CI 
at 95 percent efficiency. We note, however, that the feed to this 
source during testing comprised approximately 30 percent PCBs, known D/
F precursors.
    The Agency has considered this information and determined that it 
would be reasonable and appropriate to establish 0.20 ng/dscm (TEQ) as 
an emission level that is achievable with BTF control. Although two 
sources in our database that fed (during testing) high levels of D/F 
precursors may not have been able to achieve that level if they had 
been equipped with CI, we believe that those sources could achieve a 
level of 0.20 ng by reducing the feedrate of D/F precursors.
    We note that, because we have assumed a fairly conservative CI 
removal efficiency of 95 percent to identify the 0.20 ng/dscm BTF 
level, we believe that this adequately accounts for emissions 
variability that would be experienced at a given source attempting to 
operate under constant conditions (e.g., as during a performance test). 
That is, because CI removal efficiency is likely to be up to or greater 
than 99 percent, we believe that it is not necessary to add a 
statistically-derived variability factor to the 0.20 ng/dscm BTF level 
to account for emissions variability. Accordingly, the 0.20 ng/dscm 
(TEQ) BTF level is proposed as the emission standard.
    We invite comment on this issue, and note that if a statistically-
derived variability factor were deemed appropriate, the BTF level of 
0.20 ng/dscm would be expressed as a standard of 0.31 ng/dscm (TEQ). We 
note, however, that under this approach, it may be appropriate to use a 
less conservative CI removal efficiency (i.e., because emissions 
variability would be accounted for using statistics rather than in the 
engineering decision to use a conservative CI removal efficiency), thus 
lowering the 0.20 ng/dscm level to approximately 0.1 ng/dscm (TEQ). If 
so, the BTF standard would be approximately 0.21 ng/dscm (TEQ) (i.e., 
virtually identical to the proposed standard) after considering a 
statistically-derived variability factor.
    EPA estimates that 50 percent of incinerators are currently meeting 
a BTF level of 0.20 ng/dscm (TEQ). The incremental annualized cost for 
the remaining incinerators to meet this BTF level rather than comply 
with the floor controls would be $26.2 million, and would provide an 
incremental national reduction of 38 g/yr in D/F TEQ emissions over the 
floor level. This represents an overall reduction of about 95 percent 
compared to baseline D/F emissions of 77 g/year.
    EPA has determined that proposing a BTF MACT standard is warranted 
and a number of factors support the proposed BTF level of 0.20 ng/dscm 
(TEQ). D/F are some of the most toxic compounds known due to their 
bioaccumulation potential and wide range of health effects at 
exceedingly low doses, including carcinogenesis. Exposure via indirect 
pathways was in fact a chief reason Congress singled out D/F for 
priority MACT control in section 112(c)(6). See S. Rep. No. 228, 101st 
Cong. 1st Sess. at 154-155 (1990). As discussed elsewhere in today's 
preamble (and as qualified by the discussion below regarding small 
incinerators), EPA's risk analysis developed for purposes of RCRA in 
fact shows that D/F emissions from hazardous waste incinerators could 
pose significant risks by indirect exposure pathways and that these 
risks would be reduced by BTF controls. EPA is expressly authorized to 
consider this non-air environmental benefit in determining whether to 
adopt a BTF level. CAA section 112(d)(2).
    As discussed in Part Seven of the preamble, the cost-effectiveness 
of the BTF level for small on-site incinerators may be high. This is 
because on-site incinerators are generally smaller than commercial 
incinerators, have lower gas flow rates, and therefore have lower mass 
emission rates of D/F. Thus, the cost per gram of D/F TEQ removed for 
small incinerators is greater than for large (on-site and commercial) 
incinerators. Accordingly, the Agency invites data and comment on: (1) 
whether the BTF level is cost-effective for small incinerators; and (2) 
whether the final rule should establish MACT standards at the floor 
level (i.e., 0.20 ng/dscm (TEQ), or 400 deg. F) for these small

[[Page 17383]]

incinerators.49 50 Under this approach, the Agency would use the 
same definition of small incinerator used to identify incinerators 
subject to less frequent performance testing--incinerators with gas 
flow rates less than 23,127 acfm.51
---------------------------------------------------------------------------

    \49\ See also discussion in Part Four, Section I (Selection of 
Source Categories and Pollutants), regarding whether the Agency 
should subdivide incinerators by size and promulgate separate floor 
standards (and BTF standards, if warranted).
    \50\ If after review of comments and further analysis the Agency 
determines that subdividing incinerators is not appropriate but, 
because of cost-effectiveness considerations, BTF levels are not 
warranted for all types of incinerators, the Agency invites comment 
on whether such cost-effectiveness and BTF decisions should be based 
on incinerator size or whether the incinerator is a commercial or 
on-site unit.
    \51\ We also use this definition to request (elsewhere in the 
text) comment on whether the requirement to use Hg and PM CEMS for 
compliance monitoring should be relaxed or waived for small 
incinerators.
---------------------------------------------------------------------------

    EPA notes further that the control technology on which the proposed 
BTF standard is based, carbon injection, also controls mercury. The 
ability and efficiencies of controlling two such high toxicity HAPs 
with the same highly-efficient control technology is an important 
factor in the Agency's decision to propose a BTF standard. The Agency 
notes further that the absolute cost of achieving the proposed standard 
is relatively low, particularly considering the toxicity of D/F (as 
well as mercury, which, as just noted, would also be controlled). For 
example, the proposed BTF levels would result in annualized costs of 
$27 million to all HWIs or $15 per ton of hazardous waste burned.
    Finally, EPA's initial view is that it may be necessary to adopt 
further controls under RCRA to control D/F if it did not adopt the BTF 
level. This would defeat one of the purposes of this proposal--to avoid 
imposing emission standards under both statutes for these sources 
wherever possible. These risks would, however, be reduced to acceptable 
levels if emission levels are reduced to the proposed BTF level of 0.20 
ng/dscm (TEQ).
2. Particulate Matter
    a. MACT Floor. The Agency has a database for PM emissions from 74 
HWIs that indicates a range (by test condition average) from 0.0003 gr/
dscf to 1.9 gr/dscf. For MACT determination, the median of the best 
performing 12 percent of the HWIs in the MACT pool were analyzed and 
found to be using the following APCDs to control PM: (1) A fabric 
filter (with an air to cloth ratio of less than 10.0 acfm/ft2); 
and (2) an ionizing wet scrubber (IWS) in combination with a venturi-
scrubber. Accordingly, these APCDs were tentatively designated as the 
MACT floor technologies. To identify an emission level that these 
technologies could be expected to achieve routinely, the Agency 
examined the emissions from all incinerators (in the database) that 
were equipped with these PM control devices. A MACT floor level of 240 
mg/dscm (0.107 grains/dscf) resulted from the analysis based on 
considerations discussed in Part Three, Section V, above.
    This level, however, is higher than the current federal standard of 
180 mg/dscm (0.08 grains/dscf).\52\ Thus, the Agency is not proposing 
to use the statistically-derived approach to identify the MACT floor 
emission level. The Agency has regulated PM emissions from hazardous 
waste incinerators under RCRA (40 CFR 264.343(c)) since 1981 and all 
RCRA-permitted incinerators have been required to meet the federal 
standard of 0.08 gr/dscf (180 mg/dscm). The Agency, therefore, is 
identifying the MACT floor at the regulated level of 180 mg/dscm.
---------------------------------------------------------------------------

    \52\ This anomalous result is apparently attributable to: (1) 
inability to consider emissions from only those HWIs truly using 
MACT floor control (because of inadequate data to properly 
characterize the design, operation, and maintenance of the control 
device); and (2) use of a variability factor that is based on 
emissions variability (during trial burn testing) that may be much 
higher than many sources actually experience.
---------------------------------------------------------------------------

    The APCDs commonly used at HWIs to control PM to the current RCRA 
standard are fabric filters, ESPs, IWSs, and venturi-scrubbers. 
Accordingly, we have designated these technologies as MACT floor for PM 
control. Approximately 95 percent of all test conditions in our 
database have lower average levels (average over all runs of the test 
condition) than the MACT floor level of 180 mg/dscm.\53\ This MACT 
floor level will not impose any incremental burden on HWIs (except 
compliance and related permitting costs) since it is the currently 
enforceable level.
---------------------------------------------------------------------------

    \53\ We presume that those few test conditions that exceeded the 
180 mg/dscm standard occurred during failed trial burn tests.
---------------------------------------------------------------------------

    b. Beyond-the-Floor Considerations. The Agency considered two 
levels of more stringent BTF PM standards, 69 and 34 mg/dscm (0.03 and 
0.015 gr/dscf), since well designed and well operated ESPs, IWSs, and 
fabric filters can routinely achieve PM control at the 69 mg/dscm 
level,\54\ while state-of-the-art ESPs, IWSs and FFs can achieve 34 mg/
dscm level. The Agency is proposing a BTF standard of 69 mg/dscm (0.03 
grains/dscf) based on engineering evaluation of the emissions data from 
HWIs. (We note that, as discussed in Sections IV and V below, it also 
is consistent with the proposed standards for cement kilns and LWAKs). 
Most of the HWIs having PM emissions between 69 to 180 mg/dscm (0.03 to 
0.08 gr/dscf) range are likely to be using older APCDs that can be 
upgraded to provide better PM control. Only 30 percent of all test 
conditions \55\ in our database were found to have PM emissions greater 
than the proposed BTF level of 69 mg/dscm (0.03 gr/dscf). Analysis of 
the test data appeared to indicate that some sources operated under 
poor, non-normal conditions during one test condition resulting in high 
PM levels, while much lower PM emissions were achieved during other 
test conditions. As noted elsewhere, the Agency is specifically 
concerned that the nature of these test data (and the absence of more 
detailed, routine operations and emissions data) has interfered with 
our ability to derive MACT standards that appropriately reflect the 
lower, day-to-day emissions achievements of the best performing 
facilities. The Agency will continue to refine its analysis in this 
regard, and we specifically invite data and comments on this issue.
---------------------------------------------------------------------------

    \54\ We note also that, as discussed in the next section, cement 
kilns with much higher inlet particulate loadings are currently 
required to meet a 69 mg/dscm standard.
    \55\ Representing 20 percent of the sources.
---------------------------------------------------------------------------

    The Agency estimates that 9 percent of existing incinerators can 
achieve the proposed BTF levels using design, operation and maintenance 
upgrades of their APCDs, while 11 percent facilities would require 
installation of new fabric filters or other equivalent APCD (e.g., ESP 
or IWS). The national annualized cost to HWIs to comply with the 
proposed BTF level would be $2.7 million and would provide an 
incremental reduction of PM emissions of 839 tons/year (52 percent) 
from the baseline emissions level of 1606 tons/year. Accordingly, the 
Agency believes that a BTF level of 69 mg/dscm (0.03 gr/dscf) is 
appropriate.
    The performance of many APCDs can be improved to achieve a more 
stringent PM BTF level of 34 mg/dscm by adopting good D/O/M practices; 
in other cases, the APCD may have to be upgraded or replaced. Upgrades 
include techniques for ESPs such as humidification or increasing the 
plate area or power input, and for FFs, increasing cloth to air ratio 
and pressure drop across bags, or retrofits to modern fabrics like 
heavy woven fiberglass. The Agency is concerned, however, that the cost 
of such retrofitting to achieve PM levels of 34 mg/dscm (0.015 gr/dscf)

[[Page 17384]]

could be substantial. We also note that PM is not a HAP, but rather a 
surrogate for non-dioxin/furan HAPs adsorbed on to PM and for metal 
HAPs not directly controlled by a MACT standard. These HAPS would be 
controlled to some extent by other proposed standards (e.g., metal-
specific standards; CO and HC limits to control organic HAPs). For 
these reasons, we believe that controlling PM to the proposed BTF level 
of 69 mg/dscm (0.03 gr/dscf) is appropriate. In addition, we also note 
that the Agency has no information that a lower PM standard would be 
needed to satisfy RCRA requirements.
3. Mercury
    a. MACT floor for mercury. Mercury (Hg) emissions from incinerators 
are currently controlled by controlling the feedrate of Hg and by using 
wet scrubbers (although such scrubbers are used primarily for acid gas 
control). Wet scrubbers can remove soluble forms of mercury species 
(e.g., HgCl).
    The Agency's Hg emissions database from 29 HWIs indicates that 
baseline Hg emissions range from 0.05 g/dscm to a high of 
1,360 g/dscm. To identify MACT floor control, EPA determined 
that sources with Hg emissions at or below the level emitted by the 
median of the best performing 12 percent of sources were controlling Hg 
using either: (1) Hg feedrate control expressed as a maximum 
theoretical emission concentration (MTEC) \56\ of 19 g/dscm; 
or (2) wet scrubbers coupled with an MTEC of 51 g/dscm. 
Analysis of emissions from all incinerators in the database using these 
or better controls (i.e., lower Hg feedrates expressed as lower MTECs) 
resulted in a MACT floor level of 130 g/dscm.\57\ To meet this 
floor level 99 percent of the time, EPA estimates that a source with 
average emissions variability must be designed and operated to 
routinely meet an emission level of 57 g/dscm.
---------------------------------------------------------------------------

    \56\ MTEC is the Hg feedrate divided by the gas flow rate, and 
is an approach to normalize Hg feedrate across sources.
    \57\ As discussed above in the text, we added a within-test 
condition emissions variability factor to the log-mean of the runs 
for the test condition in the expanded MACT pool with the highest 
average emission.
---------------------------------------------------------------------------

    EPA estimates that approximately 70 percent of incinerators 
currently meet the floor level. The annualized cost for the remaining 
incinerators to meet the floor level is estimated to be $29.5 million, 
and would reduce Hg emissions nationally by 7,166 lbs per year from the 
baseline emissions level of 9,193 lbs per year.
    b. Beyond-the-Floor Considerations. The Agency has considered two 
alternative beyond-the-floor (BTF) controls for improved Hg control: 
flue gas temperature reduction to 400 deg. F or less followed by either 
activated carbon injection (CI) or carbon bed (CB). (As discussed in 
the D/F section, we note that incinerators with PM control devices 
operating below the dew point (e.g., venturi-scrubbers, ionizing wet 
scrubbers) would have to reheat the combustion gas before using CI, and 
would need to add a FF or other PM control device to remove the 
injected carbon.) EPA believes that CI-controlled systems can routinely 
achieve Hg emission reductions of 90 percent or better and that CB-
controlled systems can routinely achieve Hg emissions of 99 percent or 
better.\58\
---------------------------------------------------------------------------

    \58\ USEPA, ``Draft Technical Support Document For HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996. See also memo from Shiva Garg, EPA, 
to the Docket (No. F-96-RCSP-FFFFF), dated February 22, 1996, 
entitled ``Performance of Activated Carbon Injection On Dioxin/Furan 
and Mercury Emissions.''
---------------------------------------------------------------------------

    For CI-controlled systems, EPA has identified a BTF emission 
standard of 50 g/dscm, assuming first that a source has 
controlled its Hg emissions to only 300 g/dscm using a wet 
scrubber and/or feed control, and second, a CI removal efficiency of 90 
percent. (The BTF emission standard corresponds to a design level of 30 
g/dscm, i.e., a level that the device is designed and operated 
to achieve routinely.) \59\ For CB systems, the BTF standard would be 
5.0 g/dscm (assuming 99 percent removal efficiency).
---------------------------------------------------------------------------

    \59\ To achieve a standard of 50 g/dscm 99 percent of 
the time, a source with average emissions variability must be 
designed and operated to achieve an emission level of 30 g/
dscm.
---------------------------------------------------------------------------

    We note that another option for identifying BTF levels would be to 
consider the CI or CB system as an add on to the floor controls 
identified above. Under this option, emission levels prior to CI would 
be assumed to be the floor level, 130 g/dscm. Thus, a CI 
system at 90 percent removal could be expected to achieve a standard of 
approximately 13 g/dscm. A CB system at 99 percent removal 
could be expected to achieve a standard of approximately 1.3 
g/dscm. We specifically request comment on whether this 
approach of applying BTF reductions to the floor levels is appropriate.
    We also note that an alternative approach to using a statistically-
derived variability factor to account for emissions variability would 
be to assume a conservative control efficiency for the CI or CB BTF 
technology. We believe that using a conservative removal efficiency 
could adequately account for emissions variability. Under this 
approach, we would conservatively assume that CI-controlled systems 
could achieve a removal efficiency of 80 percent and that CB-controlled 
systems could achieve an efficiency of 90 percent. When these removal 
efficiencies are applied to the floor level of 130 g/dscm 
(corresponding to a design level of 57 g/dscm), this would 
result in emission standards of 11 g/dscm for CI-controlled 
systems, and 5.7 g/dscm for CB-controlled systems.60 We 
invite comment on this alternative approach to account for emissions 
variability among runs within a test condition.
---------------------------------------------------------------------------

    \60\ The same approach could be applied to the previously 
discussed approach of applying the BTF control to an assumed 
emission level of 300 g/dscm. When assuming the 
conservative removal efficiencies of 80 percent for CI and 90 
percent for CB, this would result in BTF standards of 60 g/
dscm for CI-controlled systems and 30 g/dscm for CB-
controlled systems. A statistically-derived variability factor would 
not be added because emissions variability is accounted for by 
assuming conservative (i.e., lower-than-expected) removal 
efficiencies for CI and CB systems.
---------------------------------------------------------------------------

    For the reasons discussed below, EPA believes that a BTF level 
based on use of CI is warranted and is proposing a MACT standard of 50 
g/dscm. The proposed standard would result in nationwide Hg 
emissions reductions of 757 lbs per year above the floor level and 
7,922 lbs per year from baseline levels, and the incremental annualized 
cost to achieve the BTF level over the floor level would be $7.7 
million.
    EPA has considered costs in relation to emissions reductions and 
the special bioaccumulation potential that Hg poses and determined that 
proposing a BTF limit is warranted. Hg is one of the more toxic metals 
known due to its bioaccumulation potential and the adverse neurological 
health effects at low concentrations especially to the most sensitive 
populations at risk (i.e., unborn children, infants and young 
children). Congress has singled out mercury in CAA section 112(c)(6) 
for prioritized control. A more detailed discussion of human health 
benefits for mercury can be found in Part Seven of today's proposal. 
The chief means of control, activated carbon injection, also controls 
D/F so that there are distinct efficiencies in control.61
---------------------------------------------------------------------------

    \61\ As discussed for D/F, we invite comment on whether the 
final rule should establish floor levels, rather than BTF levels, 
for Hg for small incinerators. This is because the Agency is 
concerned about the cost-effectiveness of the BTF levels for small 
incinerators.
---------------------------------------------------------------------------

    The Agency evaluated a more stringent standard of 8 g/dscm 
for Hg emissions based on CB technology. This standard would result in 
additional national Hg reductions of 960 lbs per year over the proposed 
standard of 50

[[Page 17385]]

g/dscm at an incremental annualized national cost of $20 
million. The Agency does not believe that a CB-based emission level of 
8 g/dscm would be appropriate.
4. Semivolatile Metals (SVM) (Cadmium and Lead)
    a. MACT Floor. Emissions of SVMs from HWIs are currently controlled 
by PM control devices. In addition, some incinerators have specific 
emission limits for these metals established under RCRA omnibus permit 
authority. The Agency has a database for SVM emissions from 42 HWIs, 
which indicates a range (by test condition average) from a low of 1.46 
to a high of 29,800 g/dscm. For the MACT analysis, the median 
of the best performing 12 percent of HWIs were found to be using: (1) a 
venturi-scrubber (VS) 62 with a MTEC level of 170 g/dscm; 
(2) a combination of ESP and WS with a MTEC level of 5,800 g/
dscm; and (3) a combination of VS and IWS with a MTEC of 49,000 
g/dscm.63 Accordingly, we identified these technologies 
as MACT floor.
---------------------------------------------------------------------------

    \62\ Because virtually all other PM control devices (e.g., ESP, 
FF, IWS) would be expected to have a SVM collection efficiency 
equivalent to or better than a VS, a source equipped with any PM 
control device and having a MTEC less than 170 g/dscm was 
considered to be using MACT floor control.
    \63\ We considered a FF to have equivalent (or better) SVM 
removal efficiency compared to an IWS. Thus, we considered a source 
equipped with a FF and any wet scrubber (ahead of the FF) and having 
a MTEC less than 49,000 g/dscm to be using MACT floor 
control. A FF alone may not provide equivalent control of SVM 
because SVM can be volatile in stack emissions.
---------------------------------------------------------------------------

    To identify an emission level that these technologies could 
routinely achieve, we evaluated the emission levels from all HWIs 
equipped with these controls.64 We identified the test condition 
in this expanded MACT pool with the highest average emission and used 
procedures discussed above in Part Three, Section V, (i.e., addition of 
a within-test condition emissions variability factor to the log mean of 
the runs for this test condition) to identify a MACT floor level 270 
g/dscm.
---------------------------------------------------------------------------

    \64\ Sources with better controls (MACT technology and lower 
feedrate expressed as MTEC) were also included in the expanded MACT 
pool.
---------------------------------------------------------------------------

    We estimate that approximately 65 percent of all incinerators 
currently meet this MACT floor level. Sources not already meeting the 
floor level can readily achieve it by making design, operation, or 
maintenance improvements to their existing PM control system or by 
retrofitting with a new PM control device.
    The national annualized cost to HWIs to comply with the proposed 
floor level is estimated to be $9.9 million, and would provide a 
reduction in Cd and Pb emissions of 50 tons/year, a 94 percent 
reduction in emissions.
    b. Beyond-the-Floor Considerations. The Agency is not proposing a 
more stringent BTF standard for SVM. We note that the floor level alone 
would provide for a 94 percent reduction in emissions, and emissions at 
the floor are not likely to trigger the need for additional control for 
these sources under RCRA.
5. Low Volatile Metals (Arsenic, Beryllium, Chromium and Antimony)
    a. MACT floor. The Agency has a database for LVM emissions from 41 
HWIs, which indicates a range (by test condition average) from a low of 
3.5 to a high of 133,000 g/dscm. For MACT analysis, the median 
of the best performing 12 percent of HWIs achieved the LVM emission 
levels using: (1) a venturi-scrubber (VS) for MTECs up to 1,000 
g/dscm; and (2) an ionizing wet scrubber (IWS) for MTECs up to 
6,200 g/dscm. Accordingly, we identified these technologies as 
MACT floor.
    In addition, we consider any PM control device to provide 
equivalent LVM control to a VS. We therefore identified an ESP, IWS, or 
FF with a MTEC up to 1,000 g/dscm as MACT floor control. 
Similarly, we consider a FF or ESP as equivalent technology to a IWS. 
Thus, a FF or ESP coupled with a MTEC up to 6,200 g/dscm is 
also considered MACT floor control.
    To identify an emission level that these technologies could 
routinely achieve, we considered the emissions from all HWIs in our 
database equipped with MACT floor control. We identified the test 
condition in this expanded MACT pool with the highest average emissions 
and added a within-test condition emissions variability factor to the 
log-mean of the test condition runs. See Part Three, Section V, above. 
Accordingly, we have identified a MACT floor level of 210 g/
dscm.
    Approximately 80 percent of all test conditions in our database 
achieved the MACT floor level even though many HWIs were equipped with 
different APCDs or had higher MTECs. EPA believes that most HWIs would 
be able to achieve the proposed MACT floor without installing an add-on 
control system. The control technologies necessary to achieve the MACT 
floor level are already being used by many HWIs for PM and acid gas 
control.
    The national annualized cost to HWIs to comply with the floor level 
would be $7.7 million and would provide an incremental reduction in LVM 
emissions of 25 tons/year (91 percent) from the baseline emissions 
level of 27.3 tons/year.
    b. Beyond-the-Floor Considerations. The Agency is not proposing a 
more stringent LVM standard using BTF controls (i.e., better performing 
PM control equipment). We note that the floor level alone would provide 
for a 91 percent reduction in emissions, and emissions at the floor are 
not likely to trigger the need for additional control for these sources 
under RCRA.
6. Hydrochloric Acid and Chlorine
    a. MACT floor for HCl/Cl2. The Agency's database for HCl/
Cl2 emissions from 59 HWIs indicates a range (by test condition 
average) from a low of 0.1 to a high of 1068 ppmv (expressed as HCl 
equivalents). For MACT analysis, the median of the best performing 12 
percent of HWIs achieving the lowest HCl/Cl2 emission levels were 
found to be using some kind of scrubbing using combinations of 
absorber, ionizing wet scrubber, VS, packed bed scrubber (PBS), or 
generic wet scrubber. In addition, the best performing sources had a 
chlorine feedrate of up to 2.1E7 g/dscm, expressed as a MTEC. 
Accordingly, we identified MACT floor control as wet scrubbing coupled 
with a chlorine MTEC up to 2.1E7 g/dscm.
    To identify an emission level that wet scrubbing with an MTEC up to 
2.1E7 g/dscm could routinely achieve, we considered the 
emissions from all HWIs in our database equipped with these controls. 
We identified the test condition in this expanded MACT pool with the 
highest average emissions and added a within-test condition emissions 
variability factor to the log-mean of the test condition runs. See Part 
Three, Section V, above. Accordingly, we have identified a MACT floor 
level of 280 ppmv.
    Over 90 percent of all test conditions in our database achieve this 
MACT floor level. At current baseline levels, HWIs emit 1712 tons/year 
of HCl/Cl2, and at today's proposed MACT standard, these emissions 
would be reduced by 592 tons/year, a reduction of 35 percent. The 
estimated annualized national cost to the industry to meet the proposed 
MACT standard would be $4.5 million.
    b. Beyond the-Floor Considerations. The Agency considered whether 
to propose a BTF level and determined that it would not be warranted. 
We note that emissions at the floor are not likely to trigger the need 
for additional control for these sources under RCRA.
7. Carbon Monoxide and Hydrocarbons
    As discussed in Section I above, the Agency believes that 
establishing emission limits and continuous

[[Page 17386]]

monitoring of two surrogate compounds (hydrocarbons (HC) and carbon 
monoxide (CO)) will help control emissions of non-dioxin organic HAPs 
(in combination with PM control to control absorbed organic HAPs).
    a. MACT Floor for HC. The Agency's database for HC emissions from 
31 HWIs indicates a range (by test condition average) from a low of 0.2 
to a high of 35.8 ppmv. Unlike certain cement kilns and LWAKs, 
incinerators are not required to monitor HC under RCRA regulations. 
Facilities generally obtained HC emissions data for their own 
information and often used an unheated FID detector, in which soluble 
volatiles and semivolatiles are condensed out before entering the 
detector. Also much of the data were based on run averages (as opposed 
to the maximum hourly rolling average format proposed today).65 
Notwithstanding these shortcomings, the Agency used these data to 
identify a MACT floor level.
---------------------------------------------------------------------------

    \65\ The average of emissions over a run is lower than the 
maximum hourly rolling average for the run. In addition, unheated 
FIDs report lower HC levels than a heated FID that would be required 
under today's proposal. Both of these factors would lead the Agency 
to underestimate the cost of compliance. On the other hand, the HC 
levels in the database were measured during worst-case, trial burn 
conditions. Thus, these emissions are likely to be much higher than 
during normal operations. This factor has lead the Agency to 
overestimate compliance costs.
---------------------------------------------------------------------------

    The Agency identified MACT control for HC as operating under good 
combustion practices (GCPs). GCPs include techniques such as thorough 
air, fuel, and waste mixing, provision of adequate excess oxygen, 
maintenance of high temperatures to destroy organics, design of the 
facility to provide high enough residence times for destruction of 
organics, operation of the facility by qualified and certified 
operators, and periodic equipment maintenance to manufacturer-
recommended standards.
    To identify the MACT floor level, the Agency conducted a 
quantitative evaluation of the data combined with engineering judgment 
to identify test conditions that appear to be conducted under good 
combustion conditions. Since it is not possible to say with certainty 
which test conditions were conducted using GCPs absent a detailed 
examination of all test conditions, we conducted the analysis by 
arraying the entire HC database from the lowest to the highest emission 
levels. We then assumed that test conditions beyond a clear break-point 
were not operated under GCPs. Based on the above analysis and a 
statistical evaluation of the level that the average source can achieve 
99 percent of the time, the Agency identified a MACT floor level of 12 
ppmv.
    We estimate that the annualized burden on HWIs to meet this floor 
level would be $8.5 million. An annual reduction of 49 tons of HC 
emissions (20 percent) is expected from the baseline levels of 239 
tons/year.
    EPA specifically invites comment on the approach used to identify 
the MACT floor level and requests HC data on a hourly rolling average 
basis, using heated FID monitors.
    b. MACT floor for CO. RCRA regulations for HWIs were promulgated in 
1981 and limit CO emissions to levels achieved during the trial burn. 
(As noted elsewhere, facilities typically design trial burns to 
maximize CO in order to provide operational flexibility.) Most of our 
database for CO (from 59 facilities) is based on run-averages during 
trial burns (rather than an hourly rolling average-basis; see 
discussion below). The CO levels in our database that are on a run-
average basis range from 0.3 to 10,400 ppmv.
    We are proposing today a maximum hourly rolling average (MHRA) 
format for CO (and HC), which is the same format in which a standard of 
100 ppmv (Tier 1) was proposed in 1990 for HWIs (see 55 FR 17862 (April 
7, 1990)) and promulgated for CKs and LWAKs in 1991 (see 56 FR 7134 
(February 21, 1991)).
    Although the Agency did not promulgate a final rule for CO 
emissions from HWIs (because of Agency resource constraints), the 
Agency published a guidance document 66 wherein a Tier 1 CO limit 
of 100 ppmv HRA was recommended for control of PIC emissions if 
warranted on a site-specific basis. Accordingly, subsequent trial burns 
for HWIs have been conducted using a HRA format for CO. Our CO database 
in the HRA format is comprised of 17 test conditions and has a range of 
10 to 1,500 ppmv.
---------------------------------------------------------------------------

    \66\ USEPA, ``Guidance on PIC Controls For Hazardous Waste 
Incinerators'', April 1990, EPA/530-SW-90-040.
---------------------------------------------------------------------------

    For MACT determination, the Agency conducted an analysis similar to 
that described above for HC and a CO MACT floor level of 120 ppmv 
resulted (e.g., MACT floor control is GCPs, and a break-point analysis 
was used to identify sources likely to be truly using GCPs). 
Nonetheless, since the Agency has previously proposed a CO limit of 100 
ppmv and since this level is readily achievable by well-designed and 
well-operated HWIs, the Agency is proposing 100 ppmv HRA as the MACT 
floor.
    We note that this floor level compares favorably with CO standards 
for other types of incinerators such as medical waste incinerators for 
which the proposed standard is 50 ppmv (60 FR 10654, February 27, 
1995), and mass burn and fluidized bed municipal waste incinerators for 
which the promulgated CO standard is 100 ppmv (60 FR 65382, December 
19,1995).
    The Agency estimates that at a 100 ppmv standard, national CO 
emission reductions of 13,200 tons/year could be achieved from the 
baseline level of 14,080 tons/year at an annualized national cost of 
$17.4 million.
    c. Beyond-the-Floor Considerations. The Agency considered more 
stringent BTF limits for CO and HC. Although state-of-the-art HWIs 
operating under GCPs should be able to routinely achieve levels below 
100 ppmv HRA for CO and 12 ppmv HRA for HC, the Agency is concerned 
that the incremental compliance cost may not warrant more stringent 
standards.
    EPA invites comments specifically on: (1) the use of CO and HC as 
surrogates for non-dioxin organic emissions; and (2) data and 
information and suggestions on an approach to identify a lower floor 
level for HC that more accurately reflects the levels that are being 
routinely achieved by HWIs operating under GCPs.
8. MACT Floor and BTF Cost Impacts
    The annualized national cost to achieve the proposed standards is 
estimated at $486,000 for each on-site incinerator unit and $731,000 
for each commercial unit. The total (pre-tax) national annualized cost 
is estimated to be $90 million for on-site and $25 million for 
commercial incinerators. These costs include a CEMS cost of $130,000 
per source annually. The most expensive HAPs would be dioxins and 
mercury, for which BTF levels have been proposed, and would cost $3.0 
million and $30 million respectively nationally at MACT floor levels, 
and $29.2 million and $37.2 million respectively at BTF levels. These 
costs include maintenance and operation of the equipment and CEMS. CEMS 
account for 18 percent of the total compliance cost. Details of these 
cost estimates have been provided in ``Second Addendum to the 
Regulatory Impact Assessment for Proposed Hazardous Waste Combustion 
Standards'' and are based on no market exit by any HWI and assuming 
that the facilities have only a limited ability to pass through the 
costs of the rule to generators.
    The Agency, however, estimates that perhaps 4 of the 34 commercial 
facility units and up to 51 of the 184 on-site facility units would 
elect to cease

[[Page 17387]]

burning hazardous wastes as a result of today's proposals. Most of 
these facilities burn small quantities of hazardous wastes. These 
facilities would likely find it more economical to transport the 
hazardous wastes to other facilities, while perhaps continuing to burn 
other non-hazardous and industrial wastes, in lieu of incurring 
expenditures to upgrade their units to continue to burn that small 
quantity of HW under MACT standards. As such, the total quantity of 
wastes burned would not be affected since those wastes would be burned 
by other HWCs, for which there appears to be sufficient capacity 
available.

B. Summary of MACT Standards For New Incinerators

1. Basis for MACT New
    According to Section 112 of CAA, the degree of reduction in 
emissions deemed achievable for new facilities may not be less 
stringent than the emissions control achieved in practice by the best 
controlled similar unit. This section summarizes EPA's rationale for 
establishing MACT standards for new HWIs. The methodology for 
determining the standards for new incinerators is similar to that for 
existing sources, except that MACT floor control is based on the single 
best performing technology, and the MACT pool is expanded to consider 
emissions from any source using that technology. For more details see 
``Draft Technical Support Document for HWC MACT Standards, Volume III: 
Selection of Proposed MACT Standards and Technologies''.
    The Agency is proposing the following standards for new HWIs:

      Table IV.3.B.1--Proposed MACT Standards for New Incinerators      
------------------------------------------------------------------------
          HAP or HAP surrogate                 Proposed standard a      
------------------------------------------------------------------------
Dioxins/furans.........................  0.2 ng/dscm TEQ.               
Particulate matter.....................  69 mg/dscm (0.030 gr/dscf).    
Mercury................................  50 g/dscm.            
SVM [Cd, Pb]...........................  62 g/dscm.            
LVM [As, Be, Cr, Sb]...................  60 g/dscm.            
HCl + Cl2..............................  67 ppmv.                       
CO.....................................  100 ppmv.                      
HC.....................................  12 ppmv.                       
------------------------------------------------------------------------
a All emission levels are corrected to 7 percent O2.                    

2. MACT New for Dioxin/Furans
    a. MACT New Floor. EPA examined its emissions database and 
identified the single best performing existing source, and found that 
the test condition with the lowest PCDD/F TEQ emissions had a test-
condition average of 0.005 ng/dscm. This facility employs a water 
quench and wet scrubbing air pollution control systems (APCSs). The D/F 
emission control by this source is being achieved by inhibiting the 
formation of D/F in the APCD by rapid quench of the hot gases from the 
combustion chamber. Therefore, the Agency selected wet scrubbing and 
low APCD inlet temperature (400 deg. F) as the MACT floor control.
    To determine an emission level that this the floor control could be 
expected to achieve, the Agency considered data from all HWIs using the 
MACT floor control. Using the same methodology as used for identifying 
the floor level for existing sources, the Agency identified a MACT 
floor level of 0.20 ng/dscm TEQ or an APCD inlet temperature of 
400 deg. F.
    b. Beyond-the-Floor (BTF) Considerations. As discussed above for 
existing sources, the Agency selected activated carbon injection (ACI) 
as the BTF technology. ACI is routinely effective in removing greater 
than 95 percent of D/F from flue gases. The Agency had identified a BTF 
level of 0.2 ng/dscm TEQ for the same reasons discussed above for the 
BTF standard for existing sources.
    The Agency also consider a carbon bed as a BTF technology to 
achieve lower emission levels. As discussed for existing sources, 
however, the Agency is concerned that the cost of carbon beds may not 
be warranted given the incremental emissions reduction over a ACI-based 
BTF standard.
3. PM Standard for New HWIs
    The single best performing source in our database for PM emissions 
was a source equipped with a FF having an air to cloth ratio of 3.8 
acfm/ft \2\. Thus, this technology represents MACT new floor control. 
When we considered emissions data from all sources equipped with this 
level of control (or better), we identified a floor level of 0.039 gr/
dscf.
    The Agency considered more efficient PM control (e.g., lower air-
to-cloth ratio, better bags) as BTF control that could achieve 
alternative BTF levels of 0.03 or 0.015 gr/dscf. These are the same 
controls investigated for BTF considerations for existing sources.
    The Agency is proposing the same BTF standard for new sources as it 
is proposing for existing sources--(69 mg/dscm or 0.03 gr/dscf). This 
standard is readily achievable. The Agency is not proposing a 0.015 gr/
dscf standard because, as discussed for existing sources, it is not 
clear that the additional cost is warranted considering the incremental 
reduction in PM.
4. Mercury Standard for New HWIs
    a. MACT New Floor. The single best performing source in our 
database for Hg emissions was a source equipped with a wet scrubber 
(WS) and having a MTEC of 51 g/dscm. The Agency considered any 
wet scrubbing device an equivalent control technology (when coupled 
with a MTEC up to 51 g/dscm) because of the ability to scrub 
soluble forms of mercury species. Thus, the Agency identified MACT new 
floor control as any wet scrubber coupled with a MTEC up to 51 
g/dscm. When we considered emissions data from all sources 
equipped with this level of control, we identified a floor level of 115 
g/dscm.
    b. Beyond-the-Floor Considerations. As for existing sources, the 
Agency considered the use of both activated carbon injection (ACI) and 
carbon bed (CB) as alternative BTF technologies. We are proposing a BTF 
standard of 50 g/dscm for new sources based on use of ACI for 
the same reasons we are proposing this standard for existing sources.
5. Semivolatile Metals Standard for New HWIs
    a. MACT New Floor. The single best performing source in our 
database for SVM emissions was a source equipped with a VS in 
combination with a IWS, and having a MTEC of 49,000 g/dscm. 
The Agency considered a wet scrubber in combination with a FF (coupled 
with a MTEC up to 49,000 g/dscm) to provide equivalent or 
better control of SVM. Thus, these technologies represent MACT new 
floor control. When we considered emissions data from all sources 
equipped with this level of control, we identified a floor level of 240 
g/dscm.
    b. Beyond-the-Floor Considerations. The Agency believes that state-
of-the-art FFs can achieve much lower emissions of SVM. For example, 
the Agency has determined that MWCs equipped with a FF can achieve more 
than a 99 percent reduction in SVM. See 59 FR 48198 (September 20, 
1994). Given that we have identified a MACT new floor (design) level 
for cement kilns of 35 g/dscm (see discussion in Section IV 
below), we believe that a design level of 35 g/dscm for HWIs 
is achievable, reasonable, and appropriate. To ensure that a source 
that is designed to meet a SVM level of 35 g/dscm can meet the 
standard 99 percent of the time (assuming the source has average 
within-test condition emissions variability for sources equipped with

[[Page 17388]]

ESPs and FFs), the Agency has established a standard of 62 g/
dscm.
    We note that SVM emissions at this level are not likely to result 
in additional regulation of these sources to satisfy RCRA health risk 
concerns.
6. Low Volatile Metals Standard for New HWIs
    a. MACT New Floor. The single best performing source in our 
database for LVM emissions was a source equipped with a VS with an MTEC 
of 1,000 g/dscm. Given the LVM collection efficiency of a VS, 
the Agency considered any PM control device (e.g., ESP, IWS, FF) to 
provide equivalent or better collection efficiency. Thus, these 
technologies represent MACT new floor control. When we considered 
emissions data from all sources equipped with this level of control, we 
identified a floor level of 260 g/dscm. (We note that this 
floor level for new sources is higher than the floor level proposed for 
existing sources. Although the statistically-derived emissions 
variability factor was added to the same test condition for both MACT 
existing floor and MACT new floor, the variability factor was greater 
for test conditions in the MACT new expanded pool.)
    b. Beyond-the-Floor Considerations. The Agency believes that state-
of-the-art PM control devices (e.g., ESPs, IWS, FFs) can achieve LVM 
emission levels well below the floor level. Given that we have 
identified a floor (design) level 67 for new CKs and new LWAKs of 
35 g/dscm and 26 g/dscm, respectively (see discussion 
in Sections IV and V below), we believe that a BTF design level of 35 
g/dscm is achievable, reasonable, and appropriate for new 
HWIs. To ensure that a source that is designed to meet a LVM level of 
35 g/dscm can meet the standard 99 percent of the time 
(assuming the source has average within-test condition emissions 
variability for sources equipped with ESPs and FFs), the Agency has 
established a standard of 60 g/dscm.
---------------------------------------------------------------------------

    \67\ That is, the log mean of runs for the test condition in the 
expanded MACT pool with the highest average emission. A within-test 
condition emissions variability factor (based on test conditions in 
the expanded MACT pool) is added to the log-mean for this test 
condition to derive the standard.
---------------------------------------------------------------------------

    We note that LVM emissions at this level are not likely to result 
in additional regulation of these sources to satisfy RCRA health risk 
concerns.
    As discussed elsewhere in today's proposal, we are encouraging but 
not requiring sources to document compliance with the metals standard 
using a multi-metal continuous monitoring system (CEMS). Given that 
available information indicates that a multi-metal CEMS could not 
effectively detect LVM emissions below 80 g/dscm, we are 
proposing an alternative standard of 80 g/dscm for sources 
that elect to document compliance with a CEMS.
7. HCl and Cl2 Standards for New HWIs
    a. MACT New Floor. The single best performing source in our 
database for HCl and Cl2 emissions was a source equipped with a 
wet scrubber with a MTEC of 1.7E7 g/dscm. The Agency 
considered any wet scrubber to be equivalent technology. Thus, MACT new 
floor control is defined as wet scrubbing with a MTEC up to 1.7E7 
g/dscm. When we considered emissions data from all sources 
equipped with this level of control, we identified a floor level of 280 
ppmv.
    b. Beyond-the-Floor Considerations. The Agency believes that state-
of-the-art wet scrubbers can readily achieve better than 99 percent 
removal of HCl and Cl2. Applying this removal efficiency to the 
test condition in our database with the highest average emission (i.e., 
1,100 ppmv; no emission control device) results in an emission of 11 
ppmv. We do not believe, however, that it is necessary to establish a 
BTF (design) level 68 this low for HCl and Cl2. Accordingly, 
we believe that it is reasonable and appropriate to establish a design 
level of 25 ppmv which corresponds to a statistically-derived standard 
of 67 ppmv.69
---------------------------------------------------------------------------

    \68\ An emissions variability factor would be added to the log-
mean of the runs of this test condition to derive a standard.
    \69\ The variability factor is based on within-test condition 
emissions variability for incinerators equipped with wet scrubbers.
---------------------------------------------------------------------------

    We note that this level is consistent with the levels we are 
proposing for new CKs (67 ppmv BTF level) and new LWAKs (62 ppmv floor 
level). Further, we note that HCl and Cl2 emissions at this level 
are not likely to result in additional regulation of these sources to 
satisfy RCRA health risk concerns.
8. Carbon Monoxide and Hydrocarbon Standards for New HWIs
    As with existing sources, CO and HC in conjunction with PM remain 
the parameters of choice to monitor continuously for controlling non-
dioxin organics. Current regulations require continuous monitoring of 
CO, but not of HC, and so the database of CO from incinerators is quite 
extensive. However, the format of our CO data is mostly on a run 
average basis as explained above. The CO levels of the best performing 
facility in this database are less than 10 ppmv hourly rolling average 
(HRA). The technology to achieve low level of non-dioxin organics is 
``Good Combustion Practices'', which is the same as for existing 
sources.
    As such, we are proposing the same MACT standards for CO and HC as 
for existing sources, but request comments on whether more stringent 
standards would be more appropriate for new sources. The promulgated 
standard for new large MWCs ranges from 50 to 150 ppmv based on type of 
the device and the Agency would like to consider more stringent levels 
for CO and HC that are representative of good combustion practices in 
new HWIs in the final rule.
9. MACT New Cost Impacts
    The annualized incremental costs (capital, operation and 
maintenance) for a small, medium and large HWI based on today's 
proposed control levels are estimated at $336K, $514K and $772K, 
respectively. Major increases are due to installing FF, activated 
carbon injection (for D/F and Hg control) and scrubbing devices (for 
acid gas control). For this analysis, it was assumed that baseline 
facilities can comply with existing regulations using a wet scrubber 
and venturi-scrubber. Since the number of new facilities starting 
construction every year is uncertain, total annualized incremental cost 
for all the new HWIs in the U.S. due to today's proposal cannot be 
estimated. The above costs include increased costs of APCS' needed 
above baseline levels, and do not include costs of the main incinerator 
system or the ancillary systems like fans, stack etc. Details of these 
costs have been provided in the ``Regulatory Impact Assessment for the 
Proposed Hazardous Waste Combustion MACT Standards''.

C. Evaluation of Protectiveness

    In order to satisfy the Agency's mandate under the Resource 
Conservation and Recovery Act to establish standards for facilities 
that manage hazardous wastes and issue permits that are protective of 
human health and the environment, the Agency conducted an analysis to 
determine if the proposed MACT standards satisfy RCRA requirements, or 
whether independent RCRA standards would be needed. These analyses were 
designed to assess both the potential risks to individuals living near 
hazardous waste combustion facilities who are highly exposed and risks 
to other less exposed individuals living near such facilities. The 
Agency evaluated potential risks both from direct inhalation exposures 
and from indirect exposures through deposition onto soils and 
vegetation and

[[Page 17389]]

subsequent uptake through the food chain. The Agency evaluated a 
variety of exposure scenarios representing various populations of 
interest, including subsistence farmers, subsistence fishers, 
recreational anglers, and home gardeners.70 In characterizing the 
risks within these populations of interest, both high-end and central 
tendency exposures were considered.
---------------------------------------------------------------------------

    \70\ In addition, the Agency evaluated a ``most exposed 
individual'' for the purpose of assessing inhalation risks. A most 
exposed individual (MEI) is operationally defined as an individual 
who resides at the location of maximum predicted ambient air 
concentration.
---------------------------------------------------------------------------

    The primary exposure parameter considered in the high-end 
characterization was exposure duration. For the baseline, 90th 
percentile stack gas concentrations were also included in the high-end 
characterization to reflect the variability in current emissions. For 
dioxins at the floor, the high-end characterization also included 90th 
percentile stack gas concentrations to reflect the large variation in 
dioxin emissions using the floor technology (i.e., temperature 
control). For the MACT standards, the Agency used the design value 
which is the value the Agency expects a source would have to design in 
order to be assured of meeting the standard on a daily basis and hence 
is always a lower value than the actual standard for all HAPs 
controlled by a variable control technology.71 The procedures used 
in the Agency's risk analyses are discussed in detail in the background 
document for today's proposal.72
---------------------------------------------------------------------------

    \71\ For the semi-volatile and low volatility metals categories, 
the Agency assumed the source could emit up to the design value for 
each metal in the category for the purpose of assessing 
protectiveness.
    \72\ ``Risk Assessment Support to the Development of Technical 
Standards for Emissions from Combustion Units Burning Hazardous 
Wastes: Background Information Document,'' February 20, 1996.
---------------------------------------------------------------------------

    The risk results for hazardous waste incinerators are summarized in 
Table III.C.1 for cancer effects and Table III.C.2 for non-cancer 
effects for the populations of greatest interest, namely subsistence 
farmers, subsistence fishers, recreational anglers, and home gardeners. 
The results are expressed as a range where the range represents the 
variation in exposures across the example facilities (and example water 
bodies for surface water pathways) for the high-end and central 
tendency exposure characterizations across the exposure scenarios of 
concern. For example, because dioxins bioaccumulate in both meat and 
fish, the subsistence farmer and subsistence fisher scenarios are used 
to determine the range.73
---------------------------------------------------------------------------

    \73\ For the semi-volatile and low volatility metals categories, 
the inhalation MEI scenarios are also used. For hydrogen chloride 
and chlorine (Cl2) only the inhalation MEI scenarios are used.

                                          Table III.C.1.--Individual Cancer Risk Estimates for Incinerators \1\                                         
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Dioxins                       Semi-volatile metals \2\               Low volatile metals \3\      
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Existing Sources                                                                    
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline.............................  2E-9 to 9E-5.........................  4E-9 to 7E-7........................  2E-10 to 4E-6                       
Floor................................  3E-9 to 5E-5 \4\.....................  5E-8 to 5E-7........................  5E-8 to 8E-6                        
BTF..................................  3E-9 to 2E-6 \5\.....................                                                                            
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       New Sources                                                                      
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Floor................................  3E-9 to 5E-5 \4\.....................  5E-8 to 5E-7........................  5E-8 to 8E-6                        
BTF..................................  3E-9 to 2E-6 \5\.....................                                                                            
CEM Option \6\.......................  .....................................  2E-8 to 2E-7........................  4E-8 to 6E-6                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Lifetime excess cancer risk.                                                                                                                        
\2\ Carcinogenic metal: cadmium.                                                                                                                        
\3\ Carcinogenic metal: arsenic, beryllium, and chromium (VI).                                                                                          
\4\ Based on 20 ng/dscm TEQ, the highest level known to be emitted at the floor.                                                                        
\5\ Based on 0.20 ng/dscm TEQ.                                                                                                                          
\6\ Based on SVM standard of 60 g/dscm and LVM standard of 80 g/dscm (applicable only if the source elects to document compliance     
  using a multi-metals CEM).                                                                                                                            


                                        Table III.C.2.--Individual Non-Cancer Risk Estimates for Incinerators \1\                                       
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                  Semi-volatile metals \2\       Low volatile metals \3\           Hydrogen chloride                  Chlorine          
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Existing Sources                                                                    
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline.....................  <0.001 to 0.02...............  <0.001 to 0.2................  0.001 to 0.05................  0.008 to 0.7                
Floor........................  <0.001 to 0.01...............  <0.001 to 0.09...............  0.02 to 0.05 \4\.............  0.07 to 0.3 \5\             
                                                                                                                                                        
                                                                       New Sources                                                                      
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Floor........................  <0.001 to 0.01...............  <0.001 to 0.09...............  0.02 to 0.05 \4\.............  0.07 to 0.3 \5\             
BTF..........................  <0.001 to 0.003..............  <0.001 to 0.03...............  0.004 to 0.01 \4\............  0.02 to 0.07 \5\            
CEM Option \6\...............  <0.001 to 0.004..............  <0.001 to 0.06...............                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Hazard quotient.                                                                                                                                    
\2\ Cadmium and lead.                                                                                                                                   
\3\ Antimony, arsenic, beryllium, and chromium.                                                                                                         
\4\ HCl+Cl 2 assuming 100 percent HCl.                                                                                                                  
\5\ HCl+Cl 2 assuming 10 percent Cl 2.                                                                                                                  
\6\ Based on SVM standard of 60 g/dscm and LVM standard of 80 g/dscm (applicable only if the source elects to document compliance     
  using a multi-metals CEM).                                                                                                                            


[[Page 17390]]


    The risk analysis indicates that for the semi-volatile and low 
volatility metals category, the MACT standards for incinerators are 
protective at the floor for both existing and new sources. The analysis 
indicates that the CEM compliance option for new sources is also 
protective. For hydrogen chloride and chlorine (Cl2), the MACT 
standards for incinerators are also protective at the floor for both 
existing and new sources. However, the analysis indicates that for 
dioxins the proposed beyond the floor standards, rather than the floor 
levels, are protective.

IV. Cement Kilns: Basis and Level for the Proposed NESHAP Standards for 
New and Existing Sources

    Today's proposal would establish new emission standards for 
dioxins/furans, mercury, semivolatile metals (cadmium and lead), low 
volatile metals (arsenic, beryllium, chromium and antimony), 
particulate matter, acid gas emissions (hydrochloric acid and 
chlorine), particulate matter (PM), hydrocarbons, and carbon monoxide 
(for the by-pass duct) from existing and new hazardous waste-burning 
cement kilns. See proposed Sec. 63.1204. The following discussion 
addresses how MACT floor and beyond-the-floor (BTF) levels were 
established for each HAP, and EPA's rationale for the proposed 
standards. The Agency's overall methodology for MACT determinations has 
been discussed in Part Three, Sections V and VI for existing sources 
and in Section VII for new sources.
    To conduct the MACT floor analyses presented today, the Agency 
compiled all available emissions data from hazardous waste-burning 
cement kilns. As noted earlier, the vast majority of this database is 
comprised of compliance test emissions data generated as a result of 
Boiler and Industrial Furnace (BIF) rule requirements.74 The 
Agency is also aware that additional emissions data will become 
available. Sources of new data include test reports generated from 
compliance recertification testing (required every three years under 
the BIF rule for interim status facilities; see Sec. 266.103(d)), 
results from voluntary industry initiatives and testing programs, 
supplemental emissions testing conducted by individual companies, and 
data from pilot-scale research by EPA's Office of Research and 
Development. As timely and appropriate, notice of these additional 
data, if used as a basis for standards in this rulemaking, will be 
published to allow for review. However, we emphasize again that, for 
purposes of setting MACT standards, it is preferable to have data that 
reflect the normal, day-to-day operations and emissions. In addition, 
the Agency believes that this type of data will substantially assist in 
the appropriate resolution of some of the issues (e.g., variability, 
proper identification of sources in MACT floor pools, raw material feed 
contributions to emissions) that are raised in the following sections. 
We invite commenters to submit this type of data and to discuss these 
issues in their comments.
---------------------------------------------------------------------------

    \74\ By August 21, 1992, or by the applicable date allowed by an 
extension by the Regional Administrator, owners and operators of BIF 
facilities burning hazardous waste were required to conduct 
compliance testing and submit a certification of compliance with the 
emissions standards for individual toxic metals, HCl, Cl 2, 
particulate matter, and CO, and where applicable, HC and dioxin/
furans. See 40 CFR Sec. 266.103(c).
---------------------------------------------------------------------------

    In addition, the Agency requests comments on whether we should use 
emissions data from cement kilns that no longer burn hazardous waste 
for MACT floor determinations.75 Even though these cement kilns 
subsequently decided to stop burning waste, we believe that their 
emissions data represent the level of emission control achieved at a 
kiln burning hazardous waste and are therefore appropriate for use in a 
MACT analysis. Moreover, the air pollution control equipment employed 
by these facilities is similar in type, design and operation to 
equipment employed by the waste-burning industry as a whole.
---------------------------------------------------------------------------

    \75\ Cement kilns no longer burning hazardous waste include 
three Southdown plants (Fairborn, OH, Knoxville, TN, and Kosmosdale, 
KY) and North Texas Cement (Midlothian, TX).
---------------------------------------------------------------------------

    The Agency conducted a preliminary analysis of the effect on MACT 
floor levels of removing these emissions data from consideration, and 
found no significant impacts (see discussion later in this section on 
MACT floor levels) other than for semivolatile metals and hydrocarbons 
in the by-pass duct. The SVM floor would rise from 57 g/dscm 
(today's proposed floor level) to approximately 1200 g/
dscm.76 This level is much higher than the cement industry can 
achieve.77 Also, the Agency notes that a SVM floor of 1200 
g/dscm may necessitate the need to consider adopting further 
controls under RCRA to address potential risks that SVMs (especially 
cadmium) may pose.78
---------------------------------------------------------------------------

    \76\ The Agency notes that we are also taking comment on a SVM 
floor level of 160 g/dscm (using an alternative approach 
discussed later in this section). A SVM floor level of 1200 
g/dscm appears unnecessarily high considering our proposed 
floor analysis and that of others (e.g., see Part Four, section 9).
    \77\ See letter from Craig Campbell, CKRC, to James Berlow, EPA, 
undated but received February 20, 1996. We note that, although the 
Agency is proposing a SVM standard of 57 g/dscm, we invite 
comment on an alternative (and potentially preferable) approach to 
identify MACT floor technology which would result in a floor-based 
standard of 160 g/dscm. See discussion on SVM floor later 
in this section. Because we identified the alternative approach late 
in the rule development process, we are inviting comment on the 
higher standard rather than proposing it.
    \78\ The Agency doubts that a MACT beyond-the-floor level would 
be warranted.
---------------------------------------------------------------------------

    In addition, the by-pass duct HC floor would be affected because 
two-thirds of the HC data available to the Agency were generated by 
these cement plants and would no longer be considered in the analysis. 
This may make calculation of the HC MACT floor problematic using the 
current MACT approach due to the limited remaining emissions data. The 
remainder of the HAP floors would remain roughly at today's proposed 
levels.
    If EPA were to decide to exclude data from cement kilns that no 
longer burn hazardous waste, the Agency then believes that emission 
data from cement kilns that have made significant modifications or 
retrofits to their manufacturing process (e.g., replacing a raw 
material with one with different characteristics, installing new 
control equipment) since the earlier emissions data were generated must 
also be considered for exclusion from MACT analysis. The Agency 
requests comment on whether we should use these emissions data (i.e., 
the data generated prior to significant process changes) in MACT 
analysis. The commenter should also address how the Agency could 
identify cement kilns that have made significant process changes and 
the scope of modifications or retrofits that would significantly impact 
emissions. Finally, since changes can affect some HAP emissions and not 
others, the commenter should address whether this issue should be 
decided on an individual HAP basis.

A. Summary of Standards for Existing Cement Kilns

    This section summarizes EPA's rationale for identifying MACT for 
existing cement kilns that burn hazardous waste and the proposed 
emission limits. The discussion of MACT includes discussions of 
``floor'' controls and considerations of ``beyond-the-floor'' controls. 
Table IV.4.A.1 summarizes the proposed emission limits.

[[Page 17391]]



 Table IV.4.A.1.--Proposed Emission Standards for Existing Cement Kilns 
------------------------------------------------------------------------
           HAP or HAP surrogate                  Proposed standard a    
------------------------------------------------------------------------
Dioxin/furans (TEQ).......................  0.20 ng/dscm (TEQ).         
Particulate Matter........................  69 mg/dscm (0.030 gr/dscf). 
Mercury...................................  50 g/dscm.         
SVM (Cd, Pb)..............................  57 g/dscm.         
LVM (As, Be, Cr, Sb)......................  130 g/dscm.        
HCl+Cl 2 (total chlorides)................  630 ppmv.                   
Hydro-carbons:                                                          
  Main Stack b............................  20 ppmv.                    
  By-pass Stack c.........................  6.7 ppmv.                   
Carbon Monoxide:                                                        
  Main Stack..............................  N/A.                        
  By-pass Stack c.........................  100 ppmv.                   
------------------------------------------------------------------------
a All emission levels are corrected to 7 percent O2.                    
b Applicable only to long wet and dry process cement kilns (i.e., not   
  applicable to preheater and/or precalciner kilns).                    
c Emissions standard applicable only for cement kilns configured with a 
  by-pass duct (typically preheater and/or precalciner kilns). Source   
  must comply with either the HC or CO standard in the by-pass duct. A  
  long wet or long dry process cement kiln that has a by-pass duct has  
  the option of meeting either the HC level in the main stack or the HC 
  or CO limit in the by-pass duct.                                      

1. Dioxin/Furans
    a. MACT Floor. The Agency's analysis of dioxin/furan (D/F) 
emissions from HWCs and other combustion devices (e.g., municipal waste 
combustors and medical waste incinerators) indicates that temperature 
of flue gas at the inlet of the PM control device can have a major 
effect on D/F emissions.79 D/F emissions generally decrease as the 
gas temperature of the PM control device decreases, and emissions are 
lowest when the gas temperature of the PM control device are below the 
optimum temperature window for D/F formation--450  deg.F to 650 
deg.F.80 Given that CKs operate their ESPs and FFs under a range 
of temperatures (i.e., from 350  deg.F to nearly 750  deg.F), the 
Agency is identifying MACT floor for D/F based on temperature control 
at the inlet to the ESP or FF.81
---------------------------------------------------------------------------

    \79\ USEPA, ``Draft Technical Support Document For HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
    \80\ For example, consider kiln #1 at the Ash Grove Cement 
Company in Chanute, Kansas. During BIF certification of compliance 
testing in 1992, Ash Grove dioxins/furans emissions exceeded 1.7 ng/
dscm (TEQ) at a control device temperature of 435  deg.F. Testing in 
1994 at a temperature of approximately 375  deg.F resulted in 
emissions less than 0.05 ng/dscm (TEQ).
    \81\ The Agency notes, however, that other factors can affect D/
F emissions including presence of precursors in the feed or as a 
result of incomplete combustion and presence of compounds thought to 
inhibit surface-catalyzed formation of D/F such as sulfur. Thus, D/F 
emissions may be low (e.g., 0.2 ng TEQ per dcsm) even though the 
temperature of stack gas at the inlet to the ESP or FF may exceed 
400-450  deg.F, and D/F emissions may be relatively high (e.g., 0.3-
0.5 ng TEQ per dscm) even though the temperature may be below that 
range.
---------------------------------------------------------------------------

    The emissions data for CKs includes results from 58 test conditions 
collected from 19 cement plants, with a total of 28 kilns being tested. 
The Agency's database shows that the average test condition D/F 
emissions ranged from 0.004 to nearly 50 ng/dscm (TEQ).
    Kilns emitting D/F at or below levels emitted by the median of the 
best performing 12 percent of kilns had flue gas temperatures at or 
below 418 deg.F at the inlet to the ESP or FF, while inlet temperatures 
for other kilns ranged to nearly 750 deg.F. The Agency then evaluated 
D/F emissions from all kilns that operated the ESP or FF at 418 deg.F 
or less and determined that 75 percent had D/F emissions less than 0.2 
ng/dscm (TEQ). The other 25 percent of kilns generally had TEQs less 
than 0.8 ng/dscm (TEQ), although one kiln emitted 4.7 ng/dscm (TEQ).
    The Agency is, therefore, identifying temperature control at the 
inlet to the ESP or FF at 418  deg.F as the MACT floor control. Given 
that 75 percent of sources achieve D/F emissions of 0.20 ng/dscm (TEQ) 
at that temperature, the Agency believes that it is appropriate to 
express the floor as ``0.20 ng/dscm (TEQ), or (temperature at the inlet 
to the ESP or FF not to exceed) 418  deg.F''. This would allow sources 
that operate at temperatures above 418  deg.F but that achieve the same 
D/F emissions as the majority of sources that operate below 418  deg.F 
(i.e., 0.20 ng/dscm (TEQ)) to meet the standard without incurring the 
expense of lowering the temperature at the ESP or FF.
    EPA estimates that over 50 percent of CKs currently are meeting the 
floor level. The national annualized compliance cost 82 for CKs to 
reduce D/F emissions to 0.20 ng/dscm (TEQ) or control ESP or FF inlet 
temperature to below 418  deg.F would be $7.3 million for the entire 
hazardous waste-burning cement industry, and would reduce D/F TEQ 
emissions nationally by 830 grams/year (TEQ) or 96 percent from current 
baseline emissions.
---------------------------------------------------------------------------

    \82\ Total annual compliance costs are before consolidation and 
do not incorporate market exit resulting from the proposed rule. 
Also, CEM costs assume that no facilities currently have a HC 
analyzer in place. Thus, these compliance costs may result in 
overstated annual compliance costs. See the ``Second Addendum to the 
Regulatory Impact Assessment for Proposed Hazardous Waste Combustion 
MACT Standards'', February 1996, for details.
---------------------------------------------------------------------------

    b. Beyond-the-Floor (BTF) Considerations. The Agency has identified 
activated carbon injection (CI) at less than 400  deg.F as a BTF 
control for D/F for cement kilns because CI is currently used in 
similar applications such as hazardous waste incinerators, municipal 
waste combustors, and medical waste incinerators. The Agency is not 
aware of any CK flue gas conditions that would preclude the 
applicability of CI or inhibit the performance of CI that has been 
demonstrated for other waste combustion applications.
    Carbon injection has been demonstrated to be routinely effective at 
removing greater than 95 percent of D/F for MWCs and MWIs and some 
tests have demonstrated a removal efficiency exceeding 99 percent at 
gas temperatures of 400  deg.F or less.83 To determine a BTF 
emission level, the Agency considered the emission levels that would be 
expected to result from gas temperature control to less than 400  deg.F 
combined with CI.
---------------------------------------------------------------------------

    \83\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
---------------------------------------------------------------------------

    To estimate emissions with temperature control only, the Agency 
considered the MACT floor database that indicates, as noted above, 25 
percent of CKs operating the ESP or FF at temperatures above 418 deg.F 
could be expected to emit D/F at levels above 0.2 ng/dscm (TEQ). 
Although the majority could be expected to emit levels of 0.8 ng/dscm 
(TEQ) or below, some could be expected to emit levels as high as 4.7 ng 
TEQ.
    When CI is used in conjunction with temperature control, an 
additional 95 percent reduction in emissions could be expected. 
Accordingly, emissions with these BTF controls could be expected to be 
less than a range of 0.04 to 0.24 ng/dscm (TEQ) (i.e., 95 percent 
reduction from 0.8 ng and 4.7 ng, respectively). Given that CI 
reductions greater than 95 percent are readily feasible, the Agency 
believes that it is appropriate to identify 0.20 ng/dscm (TEQ) as a 
reasonable BTF level that could be routinely achieved.
    The Agency notes that, because we have assumed a fairly 
conservative carbon injection removal efficiency of 95 percent to 
identify the 0.20 ng/dscm (TEQ) level, we believe that this approach 
adequately accounts for emissions variability at an individual kiln 
because CI removal efficiency is likely to be up to or greater than 99 
percent. EPA thus believes that it is not necessary to add a 
statistically-derived variability factor to the 0.20 ng/dscm (TEQ) 
level to account for emissions variability at an individual kiln. Thus,

[[Page 17392]]

the 0.20 ng/dscm (TEQ) BTF level represents the proposed emission 
standard.
    EPA solicits comment on this approach, and notes that if a 
statistically-derived variability factor were deemed appropriate with 
the assumed conservative CI removal efficiency, the BTF level of 0.20 
ng/dscm (TEQ) would be expressed as a standard of 0.31 ng/dscm (TEQ). 
We note, however, that under this approach, it may be more appropriate 
to use a less conservative, higher CI removal efficiency of 99 percent 
(i.e., because emissions variability would be accounted for using 
statistics rather than in the engineering decision to use a 
conservative CI removal efficiency). Doing so would lower the 0.20 ng/
dscm (TEQ) level to approximately 0.04 ng/dscm (TEQ) (i.e., 99 percent 
reduction from 0.8 ng and 4.7 ng results in levels of 0.008 ng to 0.047 
ng/dscm (TEQ), respectively, and 0.04 ng is a reasonable value within 
this range). If so, the D/F standard would be about 0.15 ng/dscm (TEQ) 
(i.e., 0.04 ng/dscm TEQ plus the variability factor of 0.11 ng/dscm 
TEQ).
    We note that although CI is normally a relatively inexpensive 
control technology to add to sources (with flue gas above the dew 
point) that already have PM controls at the 69 mg/dscm level, CKs 
present a special situation. This is because: (1) CI will remove Hg as 
well as D/F (see discussion below regarding BTF control for Hg); (2) 
CKs recycle as much collected PM as possible because it is useful raw 
material and doing so reduces cement kiln dust (CKD) management cost; 
(3) some CKs recycle the CKD by injecting it at the raw material feed 
end of the kiln where the D/F may not be destroyed; and (4) to remove 
Hg from the recycling system to ensure compliance with the Hg standard, 
a portion of the CKD would have to be wasted.84
---------------------------------------------------------------------------

    \84\ We note that most CKs currently dispose of a portion of CKD 
to control clinker quality (i.e., to control alkali salts). 
Nonetheless, the economics of CKD management are uncertain at this 
time given impending Agency action to ensure proper management. 
Thus, we believe that CKs will increase efforts in the future to 
minimize the amount of CKD that is disposed.
---------------------------------------------------------------------------

    Accordingly, EPA has assumed that CKs that have to use CI to meet 
the BTF standard (i.e., those that cannot achieve the standard with 
temperature control alone) would install the CI system after the 
existing ESP or FF and add a FF to remove the injected carbon with the 
adsorbed D/F (and Hg). Although adding a new FF in series is an 
expensive approach, it would enable CKs to meet both the proposed D/F 
and Hg standards (as well as the PM, SVM, and LVM standards). Thus, the 
cost of the CI and FF systems have been apportioned among these 
proposed standards.
    EPA estimates that 40 percent of CKs are currently meeting this BTF 
level. The national incremental annualized compliance cost for the 
remaining CKs to meet this BTF level 85 rather than comply with 
the floor controls would be $6.6 million for the entire hazardous 
waste-burning cement industry, and would provide an incremental 
reduction in D/F (TEQ) emissions nationally beyond the MACT floor 
controls of 20 grams/year (TEQ).
---------------------------------------------------------------------------

    \85\ We note that not every source with D/F emissions currently 
exceeding 0.20 ng TEQ per dscm would need to install CI to meet the 
standard. As noted previously in the text, 75 percent of sources 
could be expected to meet the standard with temperature control 
only. In estimating the cost of compliance with the standard, EPA 
considered the magnitude of current emissions and current operating 
temperatures to project whether the source could comply with the 
standard with temperature control only.
---------------------------------------------------------------------------

    EPA has considered costs in relation to emissions reductions and 
the special bioaccumulation potential that D/F pose and determined that 
proposing a BTF limit is warranted.86 D/F are some of the most 
toxic compounds known due to their bioaccumulation potential and wide 
range of health effects at exceedingly low doses, including 
carcinogenesis. Further, as discussed elsewhere in today's preamble, 
EPA's risk analysis developed for purposes of RCRA shows that emissions 
of these compounds from hazardous waste-burning cement kilns could pose 
significant risks by indirect exposure pathways, and that these risks 
would be reduced by BTF controls. Finally, EPA is authorized to 
consider this non-air environmental benefit in determining whether to 
adopt a BTF level. As noted earlier, exposure via these types of 
indirect pathways was in fact a chief reason Congress singled out D/F 
for priority MACT control in section 112(c)(6).
---------------------------------------------------------------------------

    \86\ We note that the D/F BTF control technology, CI, would also 
be used to control mercury emissions beyond the floor.
---------------------------------------------------------------------------

    Finally, EPA's initial view is that it may need to adopt further 
controls under RCRA to control D/F if it did not adopt the BTF MACT 
standard. This would defeat one of the purposes of this proposal, to 
avoid regulation of emissions under both statutes for these sources 
wherever possible. These risks would, however, be reduced to acceptable 
levels if emissions levels are reduced to 0.20 ng/dscm (TEQ).
    For these reasons, the Agency is proposing a BTF level of 0.20 ng/
dscm (TEQ) for D/F emitted from hazardous waste-burning cement kilns.
2. Particulate Matter
    a. MACT Floor. Cement kilns have high particulate inlet loadings to 
the control device due to the nature of the cement manufacturing 
process; that is, a significant portion of the finely pulverized raw 
material fed to the kiln is entrained in the flue gas entering the 
control device. CKs use ESPs or FFs to control PM to a 0.08 gr/dscf 
standard under the BIF rule, unless the kiln is subject to the more 
stringent New Source Performance Standard (NSPS) (see 40 CFR 60.60 
(Subpart F)) of 0.3 lb/ton of raw material feed (dry basis) to the 
kiln,87 which is generally equivalent to 69 mg/dscm or 0.03 gr/
dscf.
---------------------------------------------------------------------------

    \87\ See Sec. 60.62 Standard for particulate matter for further 
details.
---------------------------------------------------------------------------

    The PM emissions data for CKs includes results from 54 test 
conditions collected from 26 facilities, with a total of 34 units being 
tested. The Agency analyzed all available PM emissions data and 
determined that sources with emission levels at or below the level 
emitted by the median of the best performing 12 percent of sources used 
fabric filters with air-to-cloth (A/C) ratios of 2.3 acfm/ft\2\ or 
less. Analysis of emissions data from all CKs using FFs with the 2.3 
acfm/ft\2\ A/C ratio or less resulted in a level of 0.065 gr/dscf.
    Because the NSPS is a federally enforceable limit that many cement 
kilns are currently subject to, the Agency has chosen the existing NSPS 
standard, not the statistically-derived limit discussed above, as MACT 
for existing hazardous waste-burning CKs. Thus, the Agency is 
identifying a MACT floor for PM and is identifying the floor level as 
the NSPS limit of 69 mg/dscm (0.03 gr/dscf). Given that the NSPS 
standard was promulgated in 1971, the Agency believes that it is 
reasonable to consider it as the MACT floor level. We note further that 
30 percent of cement kiln test conditions currently meet the 69 mg/dscm 
floor level.
    As mentioned above, the NSPS standard for PM is expressed as 0.3 
lb/ton of raw material (dry basis) feed to the kiln. Although we are 
proposing to establish the floor level as the MACT standard (see BTF 
discussion below) expressed as 69 mg/dscm (0.03 gr/dscf), we 
specifically invite comment on whether the standard should be expressed 
in terms of raw material feed. We are proposing a ``mg/dscm'' basis for 
the standard because a PM concentration in stack gas is commonly used 
for waste combustors-hazardous waste incinerators, municipal waste

[[Page 17393]]

combustors, and medical waste incinerators. We note, however, that 
using a ``mg/dscm'' basis for the CK standard would penalize the more 
thermally efficient dry kilns (generally preheater and precalciner 
kilns). This is because these kilns have lower stack gas flow rates per 
ton of raw material feed because they do not need to provide additional 
heat (by burning hazardous waste and/or fossil fuel) to evaporate the 
water in the raw material slurry. Thus, wet kilns have higher gas flow 
rates per ton of raw material than dry kilns because of increased 
combustion gas and water vapor. This higher stack gas flow rate dilutes 
the PM emissions and effectively makes a concentration-based standard 
less stringent for wet kilns. Consequently, the Agency will consider 
whether the final rule should express the floor standard as 0.3 lb/ton 
of raw material (dry basis) feed to the kiln.
    EPA estimates that 30 percent of cement kiln test conditions (in 
our database) are currently meeting the floor level. The national 
annualized compliance cost for the remaining CKs to reduce PM emissions 
to the floor level would be $6.5 million for the entire hazardous 
waste-burning cement industry, and would reduce PM emissions nationally 
by 2400 tons per year.
    b. Beyond-the-Floor Considerations. EPA considered but is not 
proposing a more stringent beyond-the-floor level (e.g., 35 mg/dscm 
(0.015 gr/dscf)) for cement kilns. For this analysis, EPA determined 
that it does not have adequate data to ensure that, given the high 
inlet grain loading caused by entrained raw material, CKs can routinely 
achieve that emission level day-in and day-out with a single PM control 
device--ESP or FF. We note that, to ensure compliance with a 35 mg/dscm 
standard 99 percent of the time, a source with average emissions 
variability must be designed and operated to achieve an emission level 
of approximately 18 mg/dscm (or 0.008 gr/dscf). EPA estimates that 15 
percent of CKs currently have average PM emissions below 18 mg/dscm.
    Reducing the floor level from 69 mg/dscm to a BTF level of 35 mg/
dscm would require an improved technology such as the use of more 
expensive fabric filter bags (e.g., bags backed with a teflon membrane) 
or the addition of a FF for kilns with ESPs. The addition or upgrade of 
FFs to all kilns could potentially be cost effective, since to meet the 
proposed floor for SVM and LVM, as well as the proposed BTF for D/Fs 
and Hg, addition of a new FF is projected for a majority of the kilns 
(about 80 percent). Thus, a PM BTF level of 18 mg/dscm may be the 
incremental cost between a fabric filter with conventional fiberglass 
bags and state-of-the-art membrane-type bags for those kilns currently 
employing FFs; the addition of new FFs with membrane bags for those 
kilns with ESPs; or new FFs with membrane bags for the remaining 
facilities which are not projected to need upgrades to meet the floor 
and proposed BTF levels.
    At first glance it may seem cost effective, primarily since an 
improved BTF PM level would lead to added benefits with reduced SVM, 
LVM, and condensed organics emissions. However, the Agency is uncertain 
how facilities will meet the proposed SVM, LVM, D/FS, and Hg levels. 
For example, kilns could meet the mercury BTF level with feedrate 
control or carbon injection without addition of a new FF (potentially 
incurring the penalty of reduced or eliminated kiln dust recycle). 
Additionally, CKs could meet the D/F BTF level with PM control device 
temperature reduction instead of carbon injection with an add-on FF. 
Finally, kilns could meet the SVM and LVM floor levels with feedrate 
control.
    Therefore, many of the kilns may not add new FFs to comply with 
proposed floor (e.g., SVM, LVM) or proposed BTF levels (e.g., D/FS, Hg) 
and EPA's estimated engineering cost to meet the floor has been 
conservatively overstated. Thus, it may not be accurate to conclude 
that the BTF for PM is close to the incremental cost between FF fabric 
types. Under this circumstance, the incremental cost is more accurately 
the cost of many new FF unit additions which the Agency believes would 
not be cost effective. For these reasons the Agency believes it is not 
appropriate to propose a BTF PM standard of 35 mg/dscm for existing 
CKs. EPA specifically invites comment on whether the final rule should 
establish a BTF standard for PM of 35 mg/dscm (or 0.15 lb/ton of raw 
material (dry basis) feed into the kiln).
3. Mercury
    a. MACT Floor. Mercury emissions from CKs are currently controlled 
by the BIF rule, and CKs have elected to comply with the BIF standard 
by limiting the feedrate of Hg in the hazardous waste feed.88 
Thus, the MACT floor level is based on hazardous waste feed control.
---------------------------------------------------------------------------

    \88\ BIF Hg emission limits are implemented by establishing 
limits, in part, on the maximum feed rate of Hg in total 
feedstreams. Feedstream sources of mercury include hazardous waste, 
Hg spiking during compliance testing, raw material, coal and other 
fuels.
---------------------------------------------------------------------------

    Mercury emissions from cement kilns range from 3 g/dscm to 
an estimated 600 g/dscm. The Agency has Hg emissions data from 
42 test conditions collected from 21 cement plants, with a total of 28 
kilns being tested. Since mercury is a volatile compound at the typical 
operating temperatures of ESPs and baghouses, collection of mercury by 
these control devices is highly variable (e.g., Hg removal efficiencies 
ranged from zero to more than 90 percent). Most of the mercury exits 
the kiln system as volatile stack emissions, with only a small fraction 
partitioning to the clinker product or CKD.
    To identify the floor level for hazardous waste feed control, the 
Agency determined that sources with Hg emissions at or below the level 
emitted by the median of the best performing 12 percent of sources had 
normalized hazardous waste Hg feedrates, or MTECs, (i.e., maximum 
theoretical emission rates 89) of 110 g/dscm or less. 
Analysis of all existing cement kiln sources using this hazardous waste 
feedrate control resulted in a MACT floor level of 130 g/dscm. 
To meet this standard 99 percent of the time, EPA estimates that a 
source with average emissions variability 90 must be designed and 
operated to routinely achieve an emission level of 81 g/dscm.
---------------------------------------------------------------------------

    \89\ MTEC is the hazardous waste Hg feedrate divided by the gas 
flow rate.
    \90\ This represents the variability of emissions among runs 
within a test condition included within the expanded MACT pool.
---------------------------------------------------------------------------

    We note that raw materials and fossil fuels also contribute to 
cement kiln Hg feedrates and emissions. Given that all sources must be 
able to meet the floor level using the floor control, we investigated 
whether all CKs could meet the floor level by only controlling 
hazardous waste Hg feedrate to the MACT MTEC of 110 g/dscm. We 
have determined that all CKs in the Hg emissions database, except for 
one kiln with apparently anomalous data on mercury in raw material, 
would be able to meet the floor level using floor control.91 The 
one kiln reported substantially higher Hg feedrates in the raw material 
than other kilns. We believe that this data may either be erroneous or 
the kiln may have spiked Hg into the raw material during BIF compliance 
testing. We specifically invite data and comment on the issue of normal 
Hg content in raw material.
---------------------------------------------------------------------------

    \91\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
---------------------------------------------------------------------------

    EPA estimates that nearly 80 percent of CKs could currently comply 
with the floor level. The total annualized compliance cost for the 
remaining kilns

[[Page 17394]]

to reduce Hg emissions to the floor level is estimated to be up to $7.5 
million for the entire cement industry, and would reduce Hg emissions 
nationally by 7,200 lbs per year, or by 58 percent from baseline 
emissions.
    b. Beyond-the-Floor Considerations. The Agency has considered two 
BTF control options for improved Hg control: flue gas temperature 
reduction to 400 deg.F or less followed by either carbon injection (CI) 
or carbon bed (CB). Either control option would be implemented in 
conjunction with hazardous waste feedrate control of Hg. Due to the 
uncertainty surrounding the actions that cement kilns will undertake in 
achieving increased Hg control (i.e., with respect to reducing the Hg 
content of the hazardous waste received at the kiln versus installing 
the carbon injection technology to capture volatilized mercury without 
reducing Hg content in the hazardous waste feed), the Agency assumed a 
conservative emissions level attributable to feedrate control to which 
the Agency applied the BTF control technology (i.e., 300 g/
dscm). EPA believes that CI systems can routinely achieve Hg emission 
reductions of 80 to 90 percent or better 92 and that CB systems 
can routinely achieve Hg emissions of 90 to 99 percent or 
better.93
---------------------------------------------------------------------------

    \92\ Memorandum from Frank Behan, USEPA, to RCRA Docket. 
Discussion of mercury removal efficiency with activated carbon 
injection during an emissions test at a Lafarge Corporation cement 
kiln. February 26, 1996.
    \93\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
---------------------------------------------------------------------------

    The BTF level under the CI-controlled option would, therefore, be 
50 g/dscm (corresponding to a design level of 30 g/
dscm), based on 90 percent reduction after the source has controlled 
its Hg emissions to 300 g/dscm by limiting Hg in the hazardous 
waste. As discussed later, EPA is proposing a 50 g/dscm based 
on this BTF option.\94\
---------------------------------------------------------------------------

    \94\ To achieve a standard of 50 g/dscm 99 percent of 
the time, a source with average emissions variability must be 
designed and operated to achieve an emission level of 30 g/
dscm.
---------------------------------------------------------------------------

    The BTF level under the CB-controlled option would be 8 g/
dscm (corresponding to a design level of 5 g/dscm), based on 
99 percent reduction after the source has controlled its Hg emissions 
to 300 g/dscm by limiting Hg in the hazardous waste.
    We note that another control option for identifying BTF levels 
would be to consider the floor hazardous waste feedrate control--MTEC 
of 110 g/dscm or less--an initial component of BTF control 
followed by either CI or CB. Under this approach, BTF emission levels 
would be identified by first assuming sources would impose only 
feedrate controls to meet the floor level of 130 g/dscm 
(corresponding to a design level of 81 g/dscm). Thus, a CI 
injection system at 90 percent removal could be expected to achieve a 
standard of 13 g/dscm (corresponding to a design level of 8.1 
g/dscm). A CB system at 99 percent removal could be expected 
to achieve a design level of 0.8 g/dscm to which an emissions 
variability factor would be added to identify the standard. EPA 
solicits comment on whether this option of applying BTF reduction based 
on CI or CB to the floor levels should be adopted.
    We also note that an alternative approach to using a statistically-
derived variability factor to account for emissions variability would 
be to assume a more conservative control efficiency for the CI or CB 
BTF technology. We believe that using a more conservative removal 
efficiency could be a means to adequately account for emissions 
variability given that actual emissions using the BTF control would be 
expected to be lower than the assumed emission level. Under this 
approach, we would more conservatively assume that CI-controlled 
systems could achieve a removal efficiency of 80 percent and that CB-
controlled systems could achieve an efficiency of 90 percent. When 
these removal efficiencies are applied, this would result in emission 
standards of 16 g/dscm for CI-controlled systems, and 8 
g/dscm for CB-controlled systems 95. We invite comment on 
these alternative approaches to account for emissions variability at an 
individual plant.
---------------------------------------------------------------------------

    \95\ The same approach could also be utilized with the 
previously discussed approach of applying the BTF control to an 
assumed emission level of 300 g/dscm. When assuming the 
conservative removal efficiencies of 80 percent for CI and 90 
percent for CB, this would result in BTF standards of 60 g/
dscm for CI-controlled systems and 30 g/dscm for CB-
controlled systems. Again a statistically-derived variability factor 
would not be added because emissions variability is accounted for by 
assuming conservative removal efficiencies for CI and CB systems.
---------------------------------------------------------------------------

    EPA believes that CI is a cost-effective BTF control, and is 
proposing a 50 g/dscm Hg emission standard based on that 
control in conjunction with a preceding estimated hazardous waste 
feedrate control resulting in an emissions level of 300 g/dscm 
prior to the CI control. We estimate that 57 percent of CKs are 
currently meeting this level. The incremental national annualized 
compliance cost for the remaining CKs to meet this level rather than 
comply with the floor controls would be $7.8 million, and would provide 
an incremental reduction in Hg emissions of 2100 lbs per year 
nationally beyond the MACT floor controls.
    We specifically are interested in comment on whether CB is a cost 
effective BTF control 96. The CB-based BTF emission level would be 
8 g/dscm (assuming 90 percent removal efficiency). We estimate 
that 22 percent of CKs are currently meeting this level. The 
incremental national annualized compliance cost for the remaining CKs 
to meet this level rather than comply with the floor controls (and 
proposed CI-based level of 50 g/dscm) is estimated to be $34.8 
million and would provide an incremental reduction in Hg emissions 
nationally of 5,100 lbs per year from the floor.
---------------------------------------------------------------------------

    \96\ We also note that, while the Agency does not have 
information to conclude that application of the carbon bed 
technology would be problematic for cement kilns, carbon beds have 
never been tested at a full-scale cement kiln. Thus, we invite 
comment on the technical feasibility of CB control of Hg emissions 
from CKs.
---------------------------------------------------------------------------

    The Agency also invites comment on whether special consideration 
should be given to kilns that may burn hazardous waste with non-detect 
levels of Hg.97 Such kilns could be considered to be appropriately 
regulated, with respect to Hg emissions, by only the standards the 
Agency is developing for cement kilns that do not burn hazardous waste. 
Thus, today's proposed Hg standards for waste-burning kilns would be 
waived. To minimize implementation confusion and difficulties and to 
accommodate enforcement concerns, if a CK at any time burns hazardous 
waste with detectable levels of Hg, the kiln would be subject to 
today's proposed rules at all times, even if it subsequently burned 
waste with non-detect levels of Hg. Under the waiver, the owner and 
operator would be required to sample and analyze the hazardous waste as 
necessary to document that it continues to contain non-detect levels of 
Hg. We invite comment on whether such a deferral to another MACT 
standard (yet to be proposed for non-hazardous waste-burning CKs) is 
workable, given the potential for piece-meal permitting and 
enforcement.
---------------------------------------------------------------------------

    \97\ We also invite comment on what minimum detection levels 
would be acceptable.
---------------------------------------------------------------------------

    EPA has considered costs in relation to emissions reductions and 
the special bioaccumulation potential that Hg poses and determined that 
proposing a BTF limit is warranted. Hg is one of the more toxic metals 
known due to its bioaccumulation potential and the adverse neurological 
health effects at low concentrations especially to the most sensitive 
populations at risk (i.e.,

[[Page 17395]]

unborn children, infants and young children). A more detailed 
discussion of human health benefits for mercury can be found in Part 
Seven of today's proposal. The indirect exposure pathway resulting from 
airborne deposition of Hg is of particular concern, and a particular 
reason that Congress singled out Hg for priority regulation in section 
112(c)(6). See S. Rep. No. 228, 101st Cong. 1st Sess. at 153-55, 166. 
EPA is specifically authorized to take into account such non-air 
environmental benefits in assessing when to adopt BTF standards. As 
noted below, hazardous waste-burning cement kilns are a significant 
source of Hg emissions, and the BTF option will control those emissions 
from 75 percent over baseline and 47 percent over the floor. EPA 
believes the cost of controlling this especially dangerous HAP to be 
warranted in light of the extent of control, magnitude of emissions, 
limited effect on cost of treating hazardous waste (and no net effect 
on the cost of cement), and the fact that the control technology, 
carbon injection, will also control dioxins and furans. Finally, EPA 
notes that control of Hg at the BTF level should eliminate the 
uncertainty presently involved in individual RCRA permitting decisions 
where permit writers may develop site-specific permit limits beyond 
those required by current regulations if necessary to protect human 
health and the environment.
4. Semivolatile Metals
    a. MACT Floor. Emissions of SVM from CKs are currently controlled 
under the BIF rule. Kilns use a combination of hazardous waste feedrate 
control and PM control to comply with those standards. Accordingly, 
MACT floor control is based on a combination of hazardous waste 
feedrate control and PM control.
    The SVM emissions data for CKs includes results from 45 test 
conditions collected from 26 cement plants, with a total of 34 kilns 
being tested. Baseline emissions of the semivolatile metals group 
(consisting of cadmium and lead) ranged from 3 g/dscm to 
slightly over 6,000 g/dscm. Cadmium and lead are volatile at 
the usual high temperatures within the cement kilns itself, but 
typically condense onto the fine particulate at baghouse and ESP 
temperatures, where they are collected. As a result, control of 
semivolatile emissions is associated with PM control. However, because 
of the potential for adsorption for these two metals onto the fine PM 
that is less effectively collected than larger-sized PM, the control 
efficiency for semivolatile metals is likely to be lower than that for 
total PM. As discussed earlier, all cement plants currently use either 
baghouses or ESPs to control particulate emissions.
    The Agency analyzed all available Cd and Pb emissions data and 
determined that sources with emission levels at or below the level 
emitted by the median of the best performing 12 percent of sources used 
fabric filters with air-to-cloth (A/C) ratios of 2.1 acfm/ft\2\ or less 
for a kiln system with a hazardous waste MTEC of 84,000 g/dscm 
or less. Analysis of emissions data from all CKs using FFs with the 2.1 
acfm/ft\2\ A/C ratio and with a HW MTEC of 84,000 g/dscm or 
less resulted in a floor level of 57 g/dscm.
    EPA notes that raw materials and fossil fuels also contribute to 
cement kiln SVM feedrates and emissions. Given that all sources must be 
able to meet the floor level using the floor control, EPA investigated 
whether all CKs could meet the floor level employing the MACT 
technologies without being forced to substitute raw materials. Our 
preliminary evaluation determined that about 10 percent of sources had 
raw material containing Cd and Pb in greater concentrations than 
sources in the expanded MACT pool; thus, these sources may not be able 
to achieve the floor with MACT alone. 98 Before we reach any final 
conclusions on this point, the Agency believes that further data are 
needed on the normal, day-to-day levels of Pb and Cd in raw material 
feed.
---------------------------------------------------------------------------

    \98\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
---------------------------------------------------------------------------

    In addition, one approach to address this issue (of sources with 
higher levels of SVM metals in their raw materials than sources in the 
expanded MACT pool and that, therefore, cannot meet the floor level 
using floor control) is to: (1) identify the source with the highest 
normalized (by MTEC) feedrate of metals in raw material; (2) assume the 
source is also feeding hazardous waste with the floor control MTEC 
level of the metals; and (3) project SVM emissions from the source 
based on combined raw material and hazardous waste MTECs using a 
representative system removal efficiency (SRE) from the expanded MACT 
pool considering an appropriate variability factor (e.g., variability 
of emissions among runs within a test condition in the expanded MACT 
pool). The Agency has not yet conducted this type of analysis, but 
intends to do so. Again, we also believe that data reflecting normal, 
day-to-day levels of Cd and Pb in raw material feed is important in 
pursuing this avenue of analysis. We invite comment on this approach.
    The Agency also notes that the MACT pool for SVM consists entirely 
of CKs employing FF controls; that is, no cement plants with ESPs are 
in the MACT pool or expanded MACT pool. EPA believes that well 
designed, operated, and maintained ESPs can achieve good control of 
SVMs. In fact several CKS employing ESPs in our database currently 
achieve the floor level of 57 g/dscm. Because the Agency is 
concerned that the SVM floor analysis may be overly exclusive (because 
comparably designed and operated ESPs were not considered in the MACT 
floor analysis) in identifying the floor MACT level and technology, EPA 
specifically requests comment on the merits of the following 
alternative floor approach. This approach identifies comparably 
designed and operated ESPs (in our SVM database) equivalent to the MACT 
FF (and at the MACT MTEC) and includes these sources in the analysis as 
an ``equivalent technology'' of MACT. The Agency has identified an ESP 
with an SCA of 500 ft\2\/kacfm or better as an equivalent technology to 
the MACT FF with an A/C ratio of 2.1 acfm/ft\2\. The Agency conducted 
this analysis and determined that the floor level would increase from 
57 to 160 g/dscm using this approach. To meet this standard 99 
percent of the time, EPA estimates that a source with average emissions 
variability must be designed and operated to routinely achieve an 
emission level of 99 g/dscm. EPA investigated whether all CKs 
could meet the floor level employing the MACT technologies without 
being forced to substitute raw materials and determined that all CKs 
(in the SVM emissions database) with the exception of one kiln would be 
able to meet the 160 g/dscm level using this less restrictive 
MACT definition. The Agency specifically requests comment on this 
alternative floor approach and floor level.
    EPA recognizes that PM, SVM, and LVM emissions from cement kilns 
are similarly controlled, in part, by a good PM control (e.g., ESP, 
FF). The floor control for SVM (FF with an A/C ratio of 2.1 acfm/ft\2\) 
offers slightly more control than the floor control for LVM (FF with an 
A/C ratio of 2.3 acfm/ft\2\ or an ESP with a SCA of 350 ft\2\/kacfm). 
Thus, the controls necessary to achieve the SVM MACT floor level would 
appear to be governing for control of these HAPs.
    EPA estimates that 33 percent of CKs are currently meeting the 
floor level of 57 g/dscm. The national annualized compliance 
cost for the cement kilns to

[[Page 17396]]

reduce SVM emissions to the floor level would be $13.1 million, and 
would reduce national Pb and Cd emissions by 29 tons per year or 94 
percent from current baseline emissions.
    b. Beyond-the-Floor Considerations. The Agency considered whether 
to propose a more stringent level than the floor of 57 g/dscm, 
but believes that it would not be appropriate. Since control of SVM 
emissions is associated with PM control, a more stringent BTF level 
would require CKs to upgrade to more expensive fabric filter bags 
(e.g., bags backed with a teflon membrane) or the addition of a FF for 
kilns with ESPs. Even though the engineering costs to comply with a BTF 
SVM level would be modest for CKs, the resulting incremental reduction 
in SVM emissions from the floor level would be minimal. Thus, the 
Agency believes that lowering the SVM proposed standard is not 
warranted based on the minimal impact on overall SVM emissions; the 
floor already provides substantial control by reducing baseline SVM 
emissions by 94 percent. Thus, the Agency is proposing a MACT floor SVM 
standard of 57 g/dscm for existing cement kilns.
5. Low-Volatile Metals
    a. MACT Floor. Emissions of LVM from CKs are also currently 
controlled under the BIF rule. Kilns use a combination of hazardous 
waste feedrate control and PM control to comply with those standards. 
Accordingly, MACT floor control is based on a combination of hazardous 
waste feedrate control and PM control.
    The Agency has LVM emissions data which consists of 45 test 
conditions collected from 26 cement plants, with a total of 35 kilns 
being tested. Average emissions of the low volatility metals group 
(arsenic, antimony, beryllium, and chromium) ranged from 4 g/
dscm to 520 g/dscm. Due to the relatively low volatility of 
these metals, more than 70 percent of these metals typically partition 
to the clinker product while the remainder typically condense onto 
particulate and are collected in the APCD (in this case either an ESP 
or baghouse). Thus, performance of the control devices is an important 
factor in controlling LVM emissions.
    To identify MACT floor, EPA characterized the LVM controls used by 
kilns emitting LVM at levels at or below the level emitted by the 
median of the best performing 12 percent of sources. MACT floor control 
is thus defined as: (1) a baghouse (i.e., fabric filter) with an air-
to-cloth ratio of 2.3 acfm/ft \2\ or less with a hazardous waste (HW) 
MTEC less than 140,000 g/dscm; or (2) an ESP with specific 
collection area of 350 ft \2\/kacfm with a HW MTEC less than 140,000 
g/dscm. Analysis of available emissions data for all CKs 
employing either of these controls resulted in a floor emissions level 
of 130 g/dscm.
    EPA notes that raw materials and fossil fuels also contribute to 
cement kiln LVM feedrates and emissions. Given that all sources must be 
able to meet the floor level using the floor control, EPA investigated 
whether all CKs could meet the floor level employing the MACT controls 
without being forced to substitute raw material feed. EPA determined 
that all CKs would be able to meet the floor level using floor control 
without switching raw materials.99
---------------------------------------------------------------------------

    \99\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
---------------------------------------------------------------------------

    EPA estimates that 80 percent of CKs are currently meeting the 
floor level. The national annualized compliance cost for the cement 
kilns to reduce LVM emissions to the floor level would be $2.8 million 
for the entire hazardous waste-burning cement industry, and would 
reduce LVM national emissions by 1.7 tons per year or 49 percent from 
current baseline emissions.
    b. Beyond-the-Floor Considerations. The Agency considered whether 
to propose a more stringent level than the floor of 130 g/
dscm. We determined that proposing such a BTF level is not warranted 
for several reasons: (1) It would not likely be cost effective; (2) LVM 
are not of particular concern because they are not bioaccumulative; and 
(3) establishing the MACT standard at the floor would not trigger the 
need for a more stringent RCRA standard.
    Since control of LVM emissions is associated with PM control, a 
more stringent BTF level would require CKs to either install new 
control equipment or to upgrade existing control equipment (e.g., 
install more expensive FF bags). Even though the engineering costs to 
comply with a lower LVM BTF level would be moderate, the resulting 
reduction in LVM emissions is minimal since CK LVM national emissions 
are estimated to be 1.7 tons/year for the entire industry at the floor. 
Thus, a LVM BTF standard is not believed to be warranted based on this 
limited reduction in LVM emissions.
6. Hydrochloric Acid and Chlorine
    a. MACT Floor. HCl and Cl2 (also referred to as total 
chlorine) emissions from CKs are currently regulated by the BIF rule. 
CKs use the natural alkalinity of the limestone raw material and 
hazardous waste feedrate control (of total chlorine and chloride) to 
comply with those standards. No hazardous waste-burning cement kiln 
currently employs a dedicated control device (e.g., wet scrubber, 
venturi scrubber) designed specifically to remove HCl/Cl2 from the 
flue gas. Accordingly, MACT floor is based on hazardous waste feedrate 
control.100
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    \100\ Although owners and operators normally have no control 
over the control provided by raw material alkalinity, we note that 
kilns equipped with FFs appear to provide better control than kilns 
equipped with ESPs. This may be due to the longer time of contact 
between the gas stream and the alkaline dust as the gases pass 
through the dust bed on the bags.
---------------------------------------------------------------------------

    The Agency has HCl and Cl2 emissions data consists of 52 test 
conditions collected from 26 cement plants, with a total of 35 kilns 
being tested. Total chlorine emissions from cement kilns range from 
less than 0.1 ppmv to 220 ppmv. To identify MACT floor, EPA identified 
the highest hazardous waste feed MTEC (i.e., normalized hazardous waste 
feedrate of total chlorine) used by kilns emitting HCl/Cl2 at 
levels at or below the level emitted by the median of the best 
performing 12 percent of sources--1.6 g/dscm. The analysis of all 
available emissions data for kilns with a hazardous waste MTEC for 
total chlorine of 1.6 g/dscm or less resulted in a floor emissions 
level of 630 ppmv. Our data indicate that 100 percent of the test 
conditions in the Agency's database are achieving this floor value.
    This determination is confounding given that the highest average 
emissions from any test condition in the entire database, irrespective 
of hazardous waste MTEC for total chlorine, was 220 ppmv. This 
anomalous finding is apparently attributable to: (1) The data set 
having very high average within-test-condition variability; and (2) 
adding the average variability factor to the log mean rather than the 
arithmetic mean of the single test condition with the highest 
arithmetic mean within the expanded MACT pool (those sources using MACT 
floor control). If that source had unusually high emissions 
variability, then the log mean could be substantially higher than the 
arithmetic mean, resulting in an unusually high emission level to which 
the variability factor was added.
    Because of these concerns, the Agency invites comment on 
alternative approaches that may identify a more reasonable floor level. 
One approach could be to add the average variability factor for the 
data set to the arithmetic mean, rather than the log mean, of the 
highest test condition in the expanded

[[Page 17397]]

MACT pool. In addition, if this still resulted in a calculated floor 
level greater than any emission level in the database, irrespective of 
hazardous waste MTEC for total chlorine, the floor level could be 
capped at the highest emission level in the database--220 ppmv.
    As for the metals EPA notes that raw materials and fossil fuels 
also contribute to cement kiln chlorine feedrates and emissions. Given 
that all sources must be able to meet the floor level using floor 
control, EPA investigated whether all CKs could meet the floor level 
employing the MACT controls without being forced to substitute raw 
material. As discussed above, all CKs would be able to meet the floor 
level using floor control without switching raw materials.
    Sources would not incur cost to comply with the proposed floor 
level because it is higher than any baseline emission levels in the 
entire database, and there would be no emissions reductions at the 
floor level.
    b. Beyond-the-Floor Considerations. The neutralization provided 
naturally by alkaline raw materials essentially acts as a dry scrubber 
to help control HCl/Cl2 emissions. Therefore, we do not believe 
that substantial further reductions could be achieved with the use of 
dry scrubber systems. Wet scrubbers, however, could be expected to 
provide 99 percent or greater removal of HCl/Cl2.
    BTF control is therefore being defined as a wet scrubber in 
conjunction with the floor control for hazardous waste chlorine 
feedrate (defined by a MTEC of 1.6 g/dscm). Given that the proposed 
floor level based on hazardous waste chlorine feedrate control only 
would be 630 ppmv, the resulting BTF level would be 6.3 ppmv (at 99 
percent removal).
    Selecting a more effective control technology such as a wet 
scrubber would be expensive and the Agency believes that a BTF level 
would not be appropriate. For example, in one alternate investigation, 
we evaluated a 25 ppmv HCl level. The Agency estimated in that case the 
national incremental annualized compliance cost to meet this level 
would be $17 million. This represents HCl/Cl2 emissions reductions 
of 1,900 tons per year or a 71 percent reduction from baseline 
emissions. The Agency believes that the total incremental costs 
associated with a standard of 6.3 ppmv would be approximately equal to 
the incremental costs at a BTF level of 25 ppmv. We also note that, at 
a MACT floor standard of 630 ppmv, the Agency would not be required to 
establish a more stringent standard under RCRA to ensure protection of 
human health and the environment.
    In summary, the Agency is proposing a MACT floor HCl/Cl2 
standard of 630 ppmv for existing cement kilns.
7. Carbon Monoxide and Hydrocarbons
    a. MACT Floor. As discussed in Section I above, the Agency believes 
that control of non-dioxin organic HAP emissions can be achieved, in 
part, by establishing emissions limits on two surrogate compounds: (1) 
Carbon monoxide, and (2) hydrocarbons, and also by the presence of 
controls for D/F. Both CO and HCs are not listed HAPs, but the Agency 
is using them as surrogates for the enumerated organic HAPs of 
Sec. 112(b)(1) which can be non-D/F products of incomplete combustion 
(PICs). The Agency is not proposing main stack MACT standards on carbon 
monoxide for existing cement kilns for reasons discussed below; 
however, those kilns with by-pass ducts would be required to either 
comply with a separate CO or HC limit in the by-pass duct.
    i. Carbon Monoxide in the Main Stack. The Agency is not proposing a 
main stack CO limit because CO is not a universally reliable indicator 
of combustion intensity and efficiency in cement kilns due to CO 
generation by process chemistry and evolution from the trace organics 
in the raw material feedstocks.\101\ These feedstocks can generate 
large quantities of CO emissions which are unrelated to the combustion 
efficiency of burning the waste and fuel. Whereas all the CO from 
incinerators is combustion-generated, the bulk of the CO from cement 
kilns can be the result of process events unrelated to the combustion 
conditions at the burner where the wastes are introduced, or CO can be 
produced from CO2 (contained in the limestone) by dissociation at 
high sintering conditions. As a result, few cement kilns were able to 
certify compliance with the CO standard in the BIF rule 
(Sec. 266.104(b)), but instead complied with the alternative carbon 
monoxide standard of Sec. 266.104(c) that allowed CO to exceed the 100 
ppmv limit provided that stack gas concentrations of HCs did not exceed 
20 ppmv. Thus, the Agency believes it inappropriate to establish a CO 
standard measured in the main stack for all cement kilns.
---------------------------------------------------------------------------

    \101\ See 56 FR at 7150, 7153-55 (February 21, 1991).
---------------------------------------------------------------------------

    ii. Hydrocarbons in the Main Stack. CKs emit hydrocarbon (HC) 
emissions that result from incomplete combustion of fuels and 
desorption of trace levels or organic compounds from raw materials. 
These HC emissions contain organic HAPs. Organics in the raw materials 
are believed to be primarily from kerogen in the shale and limestone 
which has a porous structure allowing for organic deposits. These 
organics cause HC emissions because they are largely not destroyed 
given that combustion gases flow counter-current to the raw-materials 
(i.e., fuels are generally fired at the opposite end from where the raw 
materials are fed).
    Even when a CK is operated under good combustion conditions (and 
thus is generating low or insignificant levels of fuel-related HC), HC 
levels resulting from organics in the raw materials can range from 10 
to 400 ppmv. This makes it problematic to use HC as the only or the 
principal means to ensure good combustion efficiency of hazardous waste 
fuels to minimize emissions of toxic PICs (i.e., non-D/F organic HAPs).
    Wet Process Kilns and Long Dry Process Kilns. The BIF rule 
currently limits HC levels in the main stack (i.e., the only kiln off-
gas stack) of wet and long dry kilns to 20 ppmv. EPA is aware of five 
kilns that initially had stack HC levels exceeding the 20 ppmv limit. 
Four of the kilns changed the source of shale used as raw material to 
use a shale with lower organic content. (Shale comprises a small 
fraction of raw material feed.) The fifth kiln feeds limestone with 
(relatively) high levels of organic matter and has indicated that 
transporting an alternative source of limestone to the site may be 
prohibitively expensive. Other potential options, such as installing an 
afterburner to destroy organics or reconstructing the kiln system to 
otherwise destroy HC desorbed from the limestone, may likewise be 
prohibitively expensive approaches.
    EPA has determined that MACT floor for HC control for wet and long 
dry kilns should be control based on the current federally-enforceable 
BIF standards (i.e., control of organics in raw materials coupled with 
operating under good combustion practices to minimize fuel-related HC), 
and the floor level should be the BIF limit of 20 ppmv HC for such 
kilns. We note further that the source could stop burning hazardous 
waste and avoid having to comply with the HC floor level.
    Cement Kilns with By-pass Ducts. Kilns that are equipped with a by-
pass duct (typically preheater or precalciner kilns) to divert a 
portion of the kiln off-gas to a separate PM control device monitor 
fuel-related HC separately from raw material-related HC. This is 
because the by-pass duct diverts the kiln gas before it enters the 
calcining zone where

[[Page 17398]]

the organics from the raw material are desorbed. Thus, in general, 
fuel-related HC can be monitored in the by-pass duct, and raw material-
related HC can be monitored in the main stack. We invite comment on 
whether hazardous waste fuel combustion by-products (e.g., chlorine) 
can react with organic compounds desorbed from raw material to form 
organic HAPs. If the Agency determines that hazardous waste firing can 
substantially (adversely) affect emissions of organic HAPs from the 
main stack, then we will consider limiting HC to 20 ppmv. This is the 
limit we are proposing today for long kilns without a by-pass duct. 
Monitoring HC in the by-pass is discussed later in this section.
    The Agency's RCRA BIF rule does not control HC in the main stack of 
cement kilns that comply with the BIF HC limit in the by-pass duct 
because, under the RCRA rule, the Agency was concerned about PICs 
derived from hazardous waste combustion rather than toxic organics 
desorbed from raw materials. Therefore, any MACT standard for HC in the 
main stack of these types of kilns must be a BTF standard since the 
floor for these sources is uncontrolled, and these CKs do not otherwise 
control organic HAPs in their stack emissions.
    The Agency is concerned that main stack HC emissions contain HAPs 
for several reasons: (1) Organics desorbed from raw materials, even 
absent any influence from burning hazardous waste, contain HAPs; (2) it 
is reasonable to hypothesize that the chlorine released from burning 
hazardous waste can react with the organics desorbed from the raw 
material to form generally more toxic chlorinated HAPs; and (3) some 
preheater and precalciner kilns feed containers of hazardous waste at 
the preheater or precalciner end of the kiln near the by-pass duct 
entrance such that hazardous waste PICs may not have time to combust 
efficiently. We are concerned that these hazardous waste PICs may be 
emitted from the main stack, and that monitoring of the by-pass duct 
may not be adequate to determine if inefficient combustion occurs. This 
is because the by-pass duct gas may not be representative of kiln off-
gas when containers of hazardous waste are fed at the off-gas end of 
the kiln.
    However, the Agency does not now have sufficient data to quantify 
the contribution of hazardous waste (if there is one) to HC emissions 
in the main stack, and therefore to develop a MACT BTF standard for 
main stack HC for this class of CKs. We are thus unable to propose 
controls for HC from main stacks of cement kilns with by-pass stacks. 
We invite data to remedy this situation as well as comment on this 
issue. We also invite comment on an alternative of the same 20 ppmv 
main stack HC standard for this class of cement kilns as for the 
others.
    iii. Emissions Standards for By-pass Ducts.\102\ The Agency is 
proposing that cement kilns with by-pass ducts monitor and comply with 
either a CO or HC concentration limit in the by-pass duct because 
levels of CO and HC in the by-pass gas are more representative of 
combustion efficiency than levels in the main stack.\103\ The BIF rule 
currently limits HC (in the by-pass duct) to 20 ppmv.\104\ MACT floor 
control is operating under good combustion conditions, including 
conditions that provide adequate oxygen, temperature, turbulence, and 
residence time. These controls will ensure that kilns with low organic-
containing raw materials are operating under good combustion conditions 
to control PICs formed by the combustion of hazardous waste fuel.\105\
---------------------------------------------------------------------------

    \102\ Most precalciner and some preheater kilns are equipped 
with by-pass ducts where a portion (e.g., 5 to 30 percent) of the 
kiln exhaust is diverted to a separate APCD, and, sometimes, a 
separate stack. These gases are typically diverted to avoid a build-
up of metal salts that can adversely affect the calcination process.
    \103\ Provided that: (1) hazardous waste is fired only into the 
kiln (i.e., not at any location downstream from the kiln exit 
relative to the direction of gas flow); and (2) the by-pass duct gas 
is representative of kiln gas. To ensure by-pass gas is 
representative of kiln gas, the by-pass duct must divert a minimum 
of 10 percent of kiln off-gas as currently required in the BIF rule. 
See 266.104(g).
    \104\ The BIF rule provides for an alternative emissions 
standard for CO of 100 ppmv. See Sec. 104(f).
    \105\ When the by-pass duct is vented through a separate stack, 
compliance with limits on CO or HC would ensure application of MACT 
regarding fuel-related organic HAPs. When the by-pass is routed back 
into the main (only) stack, compliance with limits on CO or HC will 
likewise ensure application of MACT regarding fuel-related organic 
HAPs. Absent these controls on the by-pass duct, fuel-related 
organic HAPs could be either: (1) masked by raw material-related 
HAPs, if the raw material contains substantial organics; or (2) if 
the raw material contains low levels of organics, the kiln could 
comply with the main stack standard (if one were proposed) while 
operating under poor fuel combustion conditions.
---------------------------------------------------------------------------

    EPA's MACT analysis of the existing by-pass duct data of the best 
performing sources resulted in a HC MACT floor level of 6.7 ppmv. The 
Agency's database for CO in the by-pass is incomplete for the purposes 
of calculating a statistically-derived emission limit, but we believe 
that it is reasonable and appropriate to establish the by-pass CO floor 
level at the same level allowed in the BIF rule--100 ppmv. Under this 
standard the facility would have the option of complying with either 
the CO or HC standard in the by-pass duct.
    The Agency also invites comment on requiring cement kilns with by-
pass ducts to comply with both the CO and HC standard (measured in the 
by-pass duct). Given that CO in the by-pass duct should be related only 
to fuel combustion efficiency, monitoring of CO in addition to HC may 
be appropriate to ensure complete combustion of organics in the kiln; 
however, the Agency is concerned that some CO may be generated from the 
CO2 by dissociation at high sintering temperatures and thus 
requests information and data on this option.
    Cement kiln sources would not incur costs to comply with the 
proposed floor level since all cement kilns with by-pass ducts (for 
which EPA has data) currently meet the floor level for either HC or CO. 
EPA also notes that approximately half of cement kilns that measured 
both HC and CO in the by-pass achieved the floor level.
    As mentioned above, the Agency is aware of a long wet process 
cement kiln that is unable to comply with either the CO limit of 100 
ppmv or the HC limit of 20 ppmv in the main stack. This kiln cannot 
achieve either of these levels due to the relatively high organic 
matter content in the limestone. Since the majority of the raw material 
fed to the kiln is limestone, substitution with an alternative source 
of limestone with lower organic content is not readily feasible (e.g., 
prohibitively expensive transportation costs of a substitute raw 
material). The facility attempted to retrofit the kiln with a by-pass 
duct thus allowing monitoring of CO or HC in the by-pass duct as 
permitted by current BIF regulations. However, efforts to construct and 
engineer this kiln with a by-pass duct were not successful due to the 
length of the kiln.106
---------------------------------------------------------------------------

    \106\ For example, the kiln experiences a substantial increase 
in length due to expansion during start-up as the kiln heats up to 
operating levels.
---------------------------------------------------------------------------

    In coordination with state and regional officials, the cement kiln 
was retrofitted with a mid-kiln sampling port that continuously draws 
off a portion of the kiln combustion gas for analysis of HC or CO. 
Since this sampling port does not divert a minimum of 10 percent of the 
kiln off-gas from the kiln, it does not meet the Agency's current 
definition of a by-pass duct defined in Sec. 266.104(g). The kiln's 
mid-kiln sampling port diverts approximately 7 to 8 percent of the kiln 
off-gas. The Agency specifically invites comment on allowing sources 
with a mid-kiln sampling port, or other kiln gas extraction mechanism, 
that is capable of continuously extracting a representative sample of 
kiln off-gas to comply with

[[Page 17399]]

the same HC and CO standards proposed for kilns with by-pass ducts. 
Commenters should specifically address how the gas extraction system 
ensures that a representable sample of the kiln's fuel combustion gas 
would be monitored for HC or CO.
    b. Beyond-the-Floor Considerations. EPA has considered BTF control 
for organic HAP emissions from the main stack of all CKs (including 
those with by-pass ducts) based on use of a combustion gas afterburner. 
We believe that a BTF level for CO of 50 ppmv and for HC of 6 ppmv are 
readily achievable with an afterburner, but not appropriate. Therefore, 
we are not proposing such a BTF standard. EPA has no data indicating 
that any cement kilns are currently meeting these BTF levels with 
existing controls. The annualized engineering costs for the cement 
kilns to meet these BTF levels is estimated to be $280 million, and 
would provide an incremental reduction in HC emissions nationally 
beyond the floor controls of approximately 1500 tons per year and 
65,000 tons per year for CO.
8. MACT Floor Cost Impacts
    The total national annualized compliance costs 107 for 
existing cement kilns to meet all the MACT floor levels are estimated 
to be $34 million with the cost per cement kiln averaging $777,000. On 
a cost per ton of hazardous waste burned, these total compliance costs 
equate to $40 per ton of waste. We estimate that up to 2 cement 
facilities will likely cease burning hazardous waste due to the 
compliance costs associated at the floor.
---------------------------------------------------------------------------

    \107\ Compliance costs represent pre-tax compliance costs. 
Because compliance costs are tax-deductible, the portion of pre-tax 
costs borne by the firm would be between 70 and 80 percent of the 
values shown above, depending on the specific firm's margin tax 
bracket. See ``Regulatory Impact Assessment for Proposed Hazardous 
Waste Combustion MACT Standards'', November 13, 1995, for details.
---------------------------------------------------------------------------

    The Agency is proposing to go beyond-the-floor for two pollutants 
for existing cement kilns: dioxins/furans and mercury. The total 
national annualized compliance costs (i.e., total costs not incremental 
costs from the floor levels) to meet the dioxin/furan and mercury BTF 
levels in addition to the MACT floor levels for the remaining HAPs are 
estimated to be $44 million with the cost per cement kiln averaging 
$1.04 million. On a cost per ton of hazardous waste burned, these total 
compliance costs increase to $50 per ton of waste. Again, we estimate 
that up to 2 cement facilities will likely cease burning hazardous 
waste due to the compliance costs associated with the proposed 
standards.

B. MACT for New Hazardous Waste-Burning Cement Kilns

    This section summarizes EPA's rationale for establishing MACT for 
new cement kilns for each HAP, HAP surrogate, or HAP group. Table 
IV.4.B.1. summarizes the proposed emissions limits for new cement 
kilns, which were determined using the analytical process described in 
Part Three, Section VII and in the technical background document.

      Table IV.4.B.1.--Proposed MACT Standards for New Cement Kilns     
------------------------------------------------------------------------
           HAP or HAP surrogate                  Proposed standard a    
------------------------------------------------------------------------
Dioxin/furans (TEQ).......................  0.20 ng/dscm (TEQ).         
Particulate Matter........................  69 mg/dscm (0.030 gr/dscf). 
Mercury...................................  50 g/dscm.         
SVM (Cd, Pb)..............................  55 g/dscm.         
LVM (As, Be, Cr, Sb)......................  44 g/dscm.b        
HCl + Cl2 (total chlorides)...............  67 ppmv.                    
Hydrocarbons:                                                           
  Main Stack c............................  20 ppmv.                    
  By-pass Stack d.........................  6.7 ppmv.                   
Carbon Monoxide:                                                        
  Main Stack..............................  N/A.                        
  By-pass Stack d.........................  100 ppmv.                   
------------------------------------------------------------------------
a All emission levels are corrected to 7 percent O2.                    
b An alternative standard of 80 g/dscm would apply if the      
  source elects to document compliance using a multi-metals CEM.        
c Applicable only to long wet and dry process cement kilns (i.e., not   
  applicable to preheater and/or precalciner kilns).                    
d Emissions standard applicable only for cement kilns configured with a 
  by-pass duct (typically preheater and/or precalciner kilns). Source   
  must comply with either the HC or CO standard in the by-pass stack. A 
  long wet or long dry process cement kiln that has a by-pass duct has  
  the option of meeting either the HC level in the main stack or the HC 
  or CO limit in the by-pass duct.                                      

1. MACT New for Dioxins/Furans
    a. MACT New Floor. As for existing cement kilns, the Agency is 
identifying MACT new floor for D/F based on temperature control at the 
inlet to the ESP or FF. EPA characterized the single best performing 
source with the lowest TEQ dioxin/furan emissions and determined that 
the best performing source had an inlet temperature of 409 deg.F or 
less.
    The Agency then evaluated D/F emissions from all kilns that 
operated the ESP or FF at 409 deg.F or less and determined that 75 
percent had D/F emissions less than 0.2 ng/dscm (TEQ). The other 25 
percent of kilns generally had TEQs less than 0.8 ng/dscm (TEQ), 
although one kiln emitted 4.7 ng/dscm (TEQ). The Agency notes that the 
MACT new expanded pool was virtually identical (with the exception of 
two test conditions) to the expanded pool of existing sources.
    The Agency is, therefore, identifying temperature control at the 
inlet to the ESP or FF at 409 deg.F as the MACT floor control. Given 
that 75 percent of sources achieve D/F emissions of 0.20 ng/dscm (TEQ) 
at that temperature, the Agency believes that it is appropriate to 
express the floor as ``0.20 ng/dscm (TEQ), or (temperature at the inlet 
to the ESP or FF not to exceed) 409 deg.F''. This would allow sources 
that operate at temperatures above 409 deg.F but that achieve the same 
D/F emissions as the majority of sources that operate below 409 deg.F 
(i.e., 0.20 ng/dscm (TEQ)) to meet the standard without incurring the 
expense of lowering the temperature at the ESP or FF.
    b. Beyond-The-Floor Considerations. The Agency has identified 
activated carbon injection (CI) at less than 400 deg.F as a BTF control 
for D/F for cement kilns because CI is currently used in similar 
applications such as hazardous waste incinerators, municipal waste 
combustors, and medical waste incinerators. The Agency is not aware of 
any CK flue gas conditions that would preclude the applicability of CI 
or inhibit the performance of CI that has been demonstrated for other 
waste combustion applications.
    Carbon injection has been demonstrated to be routinely effective at 
removing greater than 95 percent of D/F and some tests have 
demonstrated a removal efficiency exceeding 99 percent at gas 
temperatures of 400 deg.F or less. To determine a BTF emission level, 
the Agency considered the emission levels that could result from gas 
temperature control to less than 400 deg.F combined with CI.
    As discussed for existing sources, when CI is used in conjunction 
with temperature control, an additional 95 percent reduction in 
emissions could be expected. Accordingly, emissions with BTF controls 
could be expected to be less than a range of 0.04 to 0.24 ng/dscm (TEQ) 
(i.e., 95 percent reduction from 0.8 ng and 4.7 ng, respectively). 
Given that CI reductions greater than 95 percent are readily feasible, 
the Agency believes that it is appropriate to identify 0.20 ng/dscm 
(TEQ) as a reasonable BTF level that could be routinely achieved.
    The Agency notes that, because we have assumed a fairly 
conservative carbon injection removal efficiency of 95 percent to 
identify the 0.20 ng/dscm (TEQ) level, we believe that this approach 
adequately accounts for emissions variability at an individual kiln 
because CI removal efficiency is likely to be up to or greater than 99 
percent. EPA thus believes that it is not

[[Page 17400]]

necessary to add a statistically-derived variability factor to the 0.20 
ng/dscm (TEQ) level to account for emissions variability at an 
individual kiln. Thus, the 0.20 ng/dscm (TEQ) BTF level represents the 
proposed D/F emission standard for new cement kilns.
    EPA solicits comment on this approach, and notes that if a 
statistically-derived variability factor were deemed appropriate, the 
BTF level of 0.20 ng/dscm (TEQ) would be expressed as a standard of 
0.31 ng/dscm (TEQ). We note, however, that under this approach, it may 
be more appropriate to use a less conservative CI removal efficiency 
(i.e., because emissions variability would be accounted for using 
statistics rather than in the engineering decision to use a 
conservative CI removal efficiency), thus lowering the 0.20 ng/dscm 
(TEQ) level to approximately 0.04 ng/dscm (TEQ) (i.e., 99 percent 
reduction from 0.8 ng and 4.7 ng results in levels of 0.008 ng to 0.047 
ng/dscm (TEQ), respectively, and 0.04 ng is a reasonable value within 
this range). If so, the D/F standard would be about 0.15 ng/dscm (TEQ) 
(i.e., 0.04 ng/dscm TEQ plus the variability factor of 0.11 ng/dscm 
TEQ).
    For similar reasons as discussed for existing cement kilns, the 
Agency is proposing a BTF standard for D/F of 0.20 ng/dscm (TEQ) for 
new hazardous waste-burning cement kilns. Costs for new sources are 
discussed in ``Regulatory Impact Assessment for Proposed Hazardous 
Waste Combustion MACT Standards''.
2. MACT New for Particulate Matter
    a. MACT New Floor. The Agency analyzed all available PM emissions 
data and determined that the control used by the single best performing 
source used a fabric filter with an air-to-cloth (A/C) ratio of 1.8 
acfm/ft\2\ or less. Analysis of emissions data from all CKs using FFs 
with the 1.8 acfm/ft\2\ A/C ratio or less resulted in a level of 0.065 
gr/dscf.
    For similar reasons discussed for existing cement kilns, the Agency 
has chosen the existing NSPS standard (an established regulatory 
benchmark for PM), not the statistically-derived limit, as the MACT for 
existing hazardous waste-burning cement kilns. Thus, the Agency is 
identifying a MACT floor for PM and is identifying the floor level as 
the NSPS limit of 69 mg/dscm (0.03 gr/dscf) because it is the lowest 
federally enforceable emission standard.
    b. Beyond-the-Floor Considerations. EPA considered but is not 
proposing a more stringent BTF level (e.g., 35 mg/dscm (0.0105 gr/
dscf)) for new cement kilns. For the same reasons discussed for 
existing sources, the Agency believes that a more stringent level than 
the floor is not warranted.
3. MACT New for Mercury
    a. MACT New Floor. As discussed earlier, hazardous waste-burning 
cement kilns control their mercury input (and therefore much of their 
emissions) through control of the mercury content in the hazardous 
waste. The Agency is defining the MACT floor technology as feedrate 
control with a hazardous waste MTEC less than 28 g/dscm based 
on performance of the best performing source. Analysis of all existing 
cement kiln sources using this hazardous waste feedrate control 
resulted in a MACT new floor level of 82 g/dscm. EPA estimates 
that a source with average emissions variability must be designed and 
operated to routinely achieve an emission level of 58 g/dscm 
to meet this standard 99 percent of the time. Expanded MACT pools are 
identical. The MACT new floor analysis results in the same floor as 
existing sources because their respective expanded MACT pools are 
identical.
    EPA solicits comment on an alternative method to establishing the 
MACT new floor. Under this alternative, the floor analysis would be 
similar to the approach proposed today except that the variability 
factor would be added to the average emissions from the single best 
performing source. By contrast, under the approach proposed today, the 
variability factor is added to the emissions of the highest emitting 
source in the expanded MACT pool. Thus, under this alternative the only 
purpose that expanding the MACT pool would serve is to identify the 
variability factor. EPA notes that this approach results in a MACT new 
floor of 53 g/dscm (4.4 g/dscm (average emissions 
from the best performing source) plus the statistically-derived 
variability factor of 49 g/dscm).
    b. Beyond-the-Floor Considerations. The Agency has considered the 
same BTF control alternatives for improved Hg control for new cement 
kilns: hazardous waste feedrate control of Hg in conjunction with flue 
gas temperature reduction to 400 deg.F or less followed by either 
carbon injection (CI) or carbon bed (CB). The BTF design emission level 
under the CI-controlled option is 30 g/dscm (assuming a source 
has controlled its Hg emissions to 300 g/dscm controlling Hg 
feed in the hazardous waste). The BTF emission standard corresponding 
to a design level of 30 g/dscm would be 50 g/dscm 
108. The Agency is proposing 50 g/dscm as the MACT 
standard for new cement kilns. The Agency specifically requests comment 
on establishing BTF emission standards based on the alternative 
approaches discussed for existing cement kilns.
---------------------------------------------------------------------------

    \108\ To achieve a standard of 50 g/dscm 99 percent of 
the time, a source with average emissions variability must be 
designed and operated to achieve an emission level of 30 g/
dscm.
---------------------------------------------------------------------------

4. MACT New for Semivolatile Metals
    a. MACT New Floor. MACT new control is based on hazardous waste 
feedrate control and PM control. EPA characterized the single best 
performing source with the lowest SVM emissions and determined that the 
best performing source used a fabric filter with an air-to-cloth ratio 
of 2.1 acfm/ft \2\ or less for a kiln system with a hazardous waste 
(HW) MTEC of 36,000 g/dscm or less. Analysis of all sources 
(i.e., expanded MACT pool of facilities) using this technology or 
better resulted in a floor level of 55 g/dscm for new cement 
kilns.
    EPA solicits comment on an alternative method to establishing the 
MACT new floor. Under this alternative, the floor analysis would be 
similar to approach proposed today except that the variability factor 
would be added to the average emissions from the single best performing 
source. Thus, the expanded MACT pool serves only to identify the 
variability factor of the floor technology. EPA notes that this 
approach results in a MACT new floor of 39 g/dscm (4 
g/dscm (average emissions from the best performing source) 
plus the statistically-derived variability factor of 35 g/
dscm).
    b. Beyond-the-Floor Considerations. The Agency considered a more 
stringent level than the floor level of 55 g/dscm based on 
improved collection efficiency of the MACT floor FF. Since this level 
is virtually identical to the floor level for existing sources and 
considering that EPA is not proposing standards more stringent than the 
floor for existing sources, the Agency believes for the same reasons 
that a more stringent floor level is not warranted for new sources as 
well. Finally, we note that establishing the MACT standard at the floor 
would not trigger the need for a more stringent standard under RCRA.
5. MACT New for Low-Volatile Metals
    a. MACT New Floor. MACT new control is based on hazardous waste 
feedrate control and PM control. EPA characterized the best particulate 
control device, and identified the floor technology as a baghouse 
(i.e., fabric filter) with an air-to-cloth ratio of 2.3 acfm/ft\2\ or 
less with a hazardous waste

[[Page 17401]]

(HW) MTEC less than 25,000 g/dscm. Analysis of the expanded 
MACT pool resulted in a floor emissions level of 44 g/dscm for 
new cement kilns.
    EPA solicits comment on an alternative method to establishing the 
MACT new floor. Under this alternative, the floor analysis would be 
similar to the approach proposed today except that the variability 
factor would be added to the average emissions from the single best 
performing source. Thus, the expanded MACT pool only serves to identify 
the variability factor of the floor technology. EPA notes that this 
approach results in a MACT new floor of 30 g/dscm (4 
g/dscm (average emissions from the best performing source) 
plus the statistically-derived variability factor of 26 g/
dscm).
    b. Beyond-the-Floor Considerations. The Agency considered a more 
stringent level than the floor of 44 g/dscm based on improved 
collection efficiency of the MACT floor FF. We initially determined 
that selecting such a BTF level is not warranted for several reasons: 
(1) It would not likely be cost effective considering the small 
increment of LVMs removed; (2) LVM are not of particular concern 
because they are not bioaccumulative; (3) establishing the MACT 
standard at the MACT new floor would not trigger the need for a more 
stringent RCRA standard.
    The Agency is proposing an alternative compliance option for LVMs 
for new cement kilns. Because the Agency anticipates the likelihood of 
development of a multi-metals continuous emissions monitor (CEM) in the 
near future and considering that the estimated detection limit for the 
CEM to be approximately 80 g/dscm for the LVM metals combined, 
the Agency is proposing an alternative standard of 80 g/dscm 
should the source elect to document compliance using a multi-metals 
CEM. Thus, the LVM standard is different depending on the compliance 
method selected.
6. MACT New for Hydrochloric Acid and Chlorine
    a. MACT New Floor. Cement kilns use the natural alkalinity of the 
limestone used as raw material and hazardous waste feedrate control to 
control HCl and Cl2 emissions. Thus, the MACT floor is based on 
hazardous waste feedrate control.
    EPA characterized the single best performing source with the lowest 
HCl/Cl2 emissions and determined that the best performing source 
used feedrate control with a hazardous waste (HW) MTEC of 1.6 g/dscm or 
less. (Combined emissions of HCl and Cl2 were expressed as HCl 
equivalents.) Analysis of the expanded MACT pool of facilities resulted 
in a floor level of 630 g/dscm for new cement kilns, which is 
the same result as for existing cement kiln sources because the 
expanded MACT pools are identical for both existing and new cement 
kilns.
    Again, as discussed for existing cement kilns, this determination 
is confounding given that the highest average emissions from any test 
condition in the entire database, irrespective of hazardous waste MTEC 
for total chlorine, was 220 ppmv. This anomalous finding is apparently 
attributable to: (1) The data set having very high average within-test-
condition variability; and (2) adding the average variability factor to 
the log mean rather than the arithmetic mean of the test condition 
within the expanded MACT pool (those sources using MACT floor control) 
with the highest arithmetic mean. If that source had unusually high 
emissions variability, then the log mean could be substantially higher 
than the arithmetic mean, resulting in an unusually high emission level 
to which the variability factor was added.
    Because of these concerns, the Agency invites comment on 
alternative approaches that may identify a more reasonable floor level. 
One approach could be to add the average variability factor for the 
data set to the arithmetic mean, rather than the log mean, of the 
highest test condition in the expanded MACT pool. In addition, if this 
still resulted in a calculated floor level greater than any emission 
level in the database, irrespective of hazardous waste MTEC for total 
chlorine, the floor level could be capped at the highest emission level 
in the database--220 ppmv.
    b. Beyond-the-Floor Considerations. BTF control is being defined as 
a wet scrubber in conjunction with the floor control for hazardous 
waste chlorine feedrate. As discussed earlier for existing systems, 
more stringent HCl and Cl2 control based on use of wet scrubbers 
is readily achievable. The Agency is aware of two cement kilns (not 
burning hazardous waste) that employ a wet and dry scrubber, 
respectively, capable of HCl/Cl2 capture. Wet scrubber use within 
the hazardous waste incineration industry is well established also, 
often achieving capture efficiencies exceeding 99 percent. Considering 
that average HCl/Cl2 emissions from existing cement kilns range 
from less than 1 ppmv to 220 ppmv and that a well-designed and operated 
wet scrubber would be expected to achieve removal efficiencies greater 
than 90 percent, if not higher, the Agency believes that HCl/Cl2 
control to a standard of 67 ppmv (corresponding to a design level of 25 
ppmv 109) is readily achievable.110 Thus the Agency is 
proposing a HCl/Cl2 standard of 67 ppmv for new cement kilns. See 
``Regulatory Impact Assessment for Proposed Hazardous Waste Combustion 
MACT Standards'' for further details on the costs.
---------------------------------------------------------------------------

    \109\ Considering the highest total chlorine data point of 220 
ppmv with a 90 percent removal efficiency yields a design level of 
approximately 25 ppmv.
    \110\ The Agency notes that assuming a 99 percent capture 
efficiency would result in a design level of approximately 2.2 ppmv 
(corresponding to an emission level of 6.7 ppmv). Since the 
application of wet scrubbers is still limited in the cement 
industry, EPA believes that a total chlorine standard of 6.7 ppmv is 
unnecessarily low and is thus assuming a more conservative total 
chlorine removal efficiency of 90 percent. In addition, the Agency 
notes that further controls under RCRA would not be necessary at a 
level of 67 ppmv (corresponding to a design level of 25 ppmv) for 
new cement kilns.
---------------------------------------------------------------------------

7. MACT New for Carbon Monoxide and Hydrocarbons
    a. MACT Floor. The Agency believes that control of non-dioxin 
organic HAP emissions (i.e., non-dioxin PICs that are also HAPs) can be 
achieved by establishing emissions limits on hydrocarbons and carbon 
monoxide. As discussed earlier for existing cement kilns, the Agency is 
proposing a MACT standard of 20 ppmv for HCs in the main stack (not 
applicable for preheater and precalciner kilns), and either a CO limit 
of 100 in the by-pass duct or HC standard of 6.7 ppmv in the by-pass 
duct. Thus, the proposed standards for new cement kilns are identical 
to those for existing kilns.
    b. Beyond-the-Floor Considerations. As for existing sources the 
Agency requests comment on a main stack hydrocarbon standard of 6 ppmv 
and a carbon monoxide standard of 50 ppmv for all new cement kilns 
(including those with by-pass ducts) based on performance of a 
combustion gas afterburner to burn-out incompletely combusted organics 
that escape the primary combustion zone.
8. MACT New Cost Impacts
    A discussion of the costs and economic impacts for new cement kilns 
is presented in Part Seven of today's proposal.

C. Evaluation of Protectiveness

    In order to satisfy the Agency's mandate under the RCRA to 
establish standards for facilities that manage hazardous wastes and 
issue permits that are protective of human health and the environment, 
the Agency conducted an analysis to assess the extent to which

[[Page 17402]]

potential risks from current emissions would be reduced through 
implementation of MACT standards. The analysis conducted for hazardous 
waste-burning cement kilns is similar to the one described above for 
hazardous waste incinerators. The procedures used in the Agency's risk 
analyses are described in detail in the background document for today's 
proposal.111 In evaluating the MACT standards, the Agency used the 
design value which is the value the Agency expects a source would have 
to design to in order to be assured of meeting the standard on a daily 
basis and hence is always a lower value than the actual standard for 
all HAPs controlled by a variable control technology.112
---------------------------------------------------------------------------

    \111\ ``Risk Assessment Support to the Development of Technical 
Standards for Emissions from Combustion Units Burning Hazardous 
Wastes: Background Information Document,'' February 20, 1995.
    \112\ For the semi-volatile and low volatility metals 
categories, the Agency assumed the source could emit up to the 
design value for each metal in the category for the purpose of 
assessing protectiveness.
---------------------------------------------------------------------------

    The risk results for hazardous waste-burning cement kilns are 
summarized in Table IV.4.C.1 for cancer effects and Table IV.4.C.2 for 
non-cancer effects for the populations of greatest interest, namely 
subsistence farmers, subsistence fishers, recreational anglers, and 
home gardeners. The results are expressed as a range where the range 
represents the variation in exposures across the example facilities 
(and example waterbodies for surface water pathways) for the high-end 
and central tendency exposure characterizations across the exposure 
scenarios of concern. For example, because dioxins bioaccumulate in 
both meat and fish, the subsistence farmer and subsistence fisher 
scenarios are used to determine the range.113
---------------------------------------------------------------------------

    \113\ For the semi-volatile and low volatility metals 
categories, the inhalation MEI scenarios are also used. For hydrogen 
chloride and chlorine (Cl2) only the inhalation MEI scenarios 
are used.

                       Table IV.4.C.1--Individual Cancer Risk Estimates for Cement Kilns 1                      
----------------------------------------------------------------------------------------------------------------
                                           Dioxins             Semi-volatile metals 2     Low volatile metals 3 
----------------------------------------------------------------------------------------------------------------
                                                Existing Sources                                                
                                                                                                                
----------------------------------------------------------------------------------------------------------------
Baseline........................  1E-8 to 9E-5.............  1E-9 to 4E-7.............  5E-11 to 5E-7           
Floor...........................  4E-9 to 2E-5 4...........  3E-9 to 1E-7.............  9E-9 to 4E-6            
BTF.............................  4E-9 to 2E-6 5...........                                                     
                                                                                                                
----------------------------------------------------------------------------------------------------------------
                                                   New Sources                                                  
                                                                                                                
----------------------------------------------------------------------------------------------------------------
Floor...........................  4E-9 to 2E-5 4...........  3E-9 to 1E-7.............  3E-9 to 1E-6            
BTF.............................  4E-9 to 2E-6 5...........                                                     
CEM Option 6....................  .........................  3E-9 to 1E-7.............  1E-8 to 4E-6            
----------------------------------------------------------------------------------------------------------------
1 Lifetime excess cancer risk.                                                                                  
2 Carcinogenic metal: cadmium.                                                                                  
3 Carcinogenic metals: arsenic, beryllium, and chromium (VI).                                                   
4 Based on 0.2 ng/dscm TEQ as a central tendency estimate and 1.4 ng/dscm TEQ as a high-end estimate.           
5 Based on 0.20 ng/dscm TEQ.                                                                                    
6 Based on SVM standard of 60 g/dscm and LVM standard of 80 g/dscm (applicable only if the    
  source elects to document compliance using a multi-metals CEM).                                               


                                        Table IV.4.C.2.--Individual Non-Cancer Risk Estimates for Cement Kilns 1                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                        Semi-volatile metals 2        Low volatile metals 3          Hydrogen chloride                 Chlorine         
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Existing Sources                                                                    
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline...........................  <0.001 to 0.06..............  <0.001 to 0.004............  <0.001 to 0.04.............  <0.001 to 0.06             
Floor..............................  <0.001 to 0.004.............  <0.001 to 0.01.............  0.01 to 0.1 4..............  0.05 to 0.8 5              
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       New Sources                                                                      
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Floor..............................  <0.001 to 0.004.............  <0.001 to 0.005............  0.01 to 0.1 4..............  0.05 to 0.8 5              
BTF................................  ............................  ...........................  0.001 to 0.01 4............  0.005 to 0.08 5            
CEM Option 6.......................  <0.001 to 0.004.............  <0.001 to 0.01.............  ...........................  ...........................
--------------------------------------------------------------------------------------------------------------------------------------------------------
1 Hazard quotient.                                                                                                                                      
2 Cadmium and lead.                                                                                                                                     
3 Antimony, arsenic, beryllium, and chromium.                                                                                                           
4 HCl + Cl2 assuming 100 percent HCl.                                                                                                                   
5 HCl + Cl2 assuming 10 percent Cl2.                                                                                                                    
6 Based on SVM standard of 60 g/dscm and LVM standard of 80 g/dscm (applicable only if the source elects to document compliance using 
  a multi-metals CEM).                                                                                                                                  

    The risk analysis indicates that for the semi-volatile and low-
volatile metals categories, the MACT standards for cement kilns are 
protective at the floor for both existing and new sources. The analysis 
indicates that the CEM compliance option for new sources is also 
protective. For hydrogen chloride and chlorine (Cl2), the MACT 
standards for cement kilns are also protective at the floor for both 
existing and new sources. However, the analysis indicates

[[Page 17403]]

that for dioxins the proposed beyond the floor standards, rather than 
the floor levels, are protective.

V. Lightweight Aggregate Kilns: Basis and Level for the Proposed NESHAP 
Standards for New and Existing Sources

    Today's proposal would establish maximum achievable control 
technology (MACT) emissions standards for dioxin/furans, mercury, 
semivolatile metals (cadmium and lead), low volatile metals (arsenic, 
beryllium, chromium, and antimony), particulate matter (PM), acid gas 
emissions (hydrochloric acid plus chlorine), hydrocarbons, and carbon 
monoxide from existing and new hazardous waste-burning lightweight 
aggregate kilns (LWAKs). See proposed Sec. 63.1205. The following 
discussion addresses how MACT floor and beyond-the-floor (BTF) levels 
were established for each HAP and EPA's rationale for the proposed 
standard. The Agency's overall procedural approach for MACT 
determinations has been discussed in Part Three, Sections V and VI for 
existing sources and in Section VII for new sources.
    Again, the Agency wishes to emphasize that these standards were 
developed using a database that contains primarily short-term 
certification of compliance data that may not adequately reflect more 
normal, day-to-day operations and emissions. As noted earlier, EPA 
believes it preferable to use long-term, more normal operating 
emissions data for MACT standard-setting purposes and specifically 
invites commenters to submit this type of data.

A. Summary of MACT Standards for Existing LWAKs

    This section summarizes EPA's rationale for establishing the MACT 
floor emission level and choosing MACT for existing LWAKs for each HAP, 
HAP surrogate, or HAP group.
    Table IV.5.A.1 summarizes the MACT standards for existing LWAKs. 
The basis for the floor level and BTF considerations for each HAP or 
HAP surrogate is then discussed.

       Table IV.5.A.1.--Proposed MACT Standards for Existing LWAKs      
------------------------------------------------------------------------
           HAP or HAP surrogate                Proposed standards \1\   
------------------------------------------------------------------------
Dioxin/furans.............................  0.20 ng/dscm TEQ.           
Particulate Matter........................  0.030 gr/dscf (69 mg/dscm)  
Mercury...................................  72 g/dscm.         
SVM [Cd, Pb]..............................  12 g/dscm.\2\      
LVM [As, Be, Cr, Sb]......................  340 g/dscm.        
HCl + Cl2.................................  450 ppmv.                   
CO........................................  100 ppmv.                   
HC........................................  14 ppmv.                    
------------------------------------------------------------------------
\1\ All emission levels are corrected to 7 percent O2.                  
\2\ An alternative standard of 60 g/dscm would apply if the    
  source elects to document compliance using a multi-metals CEM.        

1. Dioxin/Furans
    a. MACT Floor. EPA has obtained dioxin/furan (D/F) emissions data 
for only one LWAK. The data indicated an average test condition D/F 
emission of 0.04 ng/dscm (TEQ). Based on the Agency's data on the 
performance of D/F control technology, the Agency is identifying the 
MACT floor for D/F based on temperature control at the inlet to the 
fabric filter. EPA is therefore identifying the MACT floor level for D/
F emissions from LWAKs as 0.20 ng/dscm (TEQ) or (temperature at the PM 
control device not to exceed) 418 deg. F.
    Given that EPA is not aware of any LWAKs that exceed the floor 
level, the rule would not require these sources to incur costs to 
achieve compliance.
    The Agency recognizes that its data on dioxin/furan emissions from 
LWAKs is limited. Therefore, the Agency is inviting commenters to 
submit additional performance data on LWAK D/F emissions.
    b. Beyond-The-Floor Considerations. The BTF considerations for 
LWAKs were the same as for CKs. Therefore, EPA is proposing a BTF 
standard of 0.20 ng/dscm (TEQ) for the same reasons applicable to CKs. 
As noted above, given that EPA is not aware of any LWAKs that exceed 
the proposed BTF standard, LWAKs should not have to incur costs to 
achieve compliance. EPA notes, however, that LWAKs would nonetheless be 
required to comply with operating limits established during performance 
testing and conduct periodic D/F testing to document compliance with 
the rule. These costs are relatively low when compared to the cost of 
complying with other provisions of today's rule.
2. Particulate Matter
    a. MACT Floor. LWAKs, like cement kilns, have high particulate 
inlet loadings to the particulate control device due to the nature of 
the lightweight aggregate manufacturing process; that is, a significant 
portion of the finely pulverized raw material fed to the kiln is 
entrained in the flue gas entering the control device. LWAKs are 
equipped with fabric filters, although one facility is equipped with a 
spray dryer, venturi scrubber and wet scrubber, in addition to the 
fabric filter, to control PM to a 0.08 gr/dscf standard under the BIF 
rule. The PM data for LWAKs include results from 15 test conditions 
collected from 6 facilities, with a total of 12 units being tested. The 
Agency's database shows that the average controlled PM emissions ranged 
from 0.0005 gr/dscf to 0.02 gr/dscf, corrected to 7 percent oxygen, dry 
basis.
    The Agency analyzed all available PM emissions data and determined 
that sources with emission levels at or below the level emitted by the 
median of the best performing 12 percent of sources used a fabric 
filter with an air-to-cloth ratio of 2.8 acfm/ft2 or less. EPA's 
analysis of all LWAKs employing this floor technology resulted in a 
MACT floor emissions level of 110 mg/dscm (0.049 gr/dscf). EPA 
estimates that 100 percent of LWAKs are currently meeting the floor 
level. The national annualized compliance cost for LWAKs to meet the 
floor level is estimated to be $290,000 for the entire LWAK industry.
    b. Beyond-The-Floor Considerations. EPA is proposing a more 
stringent beyond-the-floor (BTF) level of 69 mg/dscm (0.03 gr/dscf) for 
LWAKs. As mentioned above, since 1971, some cement kilns have been 
subject to the more stringent NSPS (see 40 CFR 60.60, Subpart F) of 0.3 
lb/ton of raw material feed (dry basis) to the kiln, which is generally 
equivalent to 69 mg/dscm (0.03 gr/dscf). Because of design and process 
similarities between LWAKs and cement kilns, such as high inlet grain 
loading and similar APCDs, the Agency believes that 69 mg/dscm is 
achievable for LWAKs.
    EPA estimates that 80 percent of LWAKs are currently meeting this 
BTF level. The Agency estimates that there would be no national 
incremental annualized compliance cost for the remaining LWAKs to meet 
the BTF level rather than comply with the floor controls. This is 
because sources are already meeting the BTF level, or they would be 
able to meet it with the upgrades or retrofits needed to meet the floor 
level. The BTF level would provide an incremental reduction of 4 tons 
per year, or 9 percent, in PM emissions nationally beyond that achieved 
with floor controls. (Note that emissions reductions estimates are 
based on the design level, not the standard.) Therefore, the Agency is 
proposing a MACT standard of 69 mg/dscm (0.030 gr/dscf) for existing 
LWAKs.
    EPA considered but is not proposing an alternative more stringent 
beyond-

[[Page 17404]]

the-floor level (e.g., 35 mg/dscm (0.015 gr/dscf)) for LWAKs. EPA notes 
that, to ensure compliance with a 35 mg/dscm standard 99 percent of the 
time, a source with average emissions variability must be designed and 
operated to achieve an emission level of approximately 18 mg/dscm. EPA 
estimates that 60 percent of LWAKs currently have average PM emissions 
below 18 mg/dscm.
    All of the remaining LWAKs may require the installation of new 
fabric filters to comply with the proposed standards for all HAPs 
discussed in today's rule. The average emissions level for the 40 
percent of LWAKs that do not meet a PM emission level of 18 mg/dscm is 
28 mg/dscm. All of these LWAKs would require an upgrade from fiberglass 
bags to improved performance filter media on the newly installed fabric 
filters. Although the engineering costs to comply with a PM design 
level of 18 mg/dscm is modest for LWAKs, the resulting reduction in PM 
emissions is minimal because 40 percent of the kilns are emitting at an 
average emission level slightly above the BTF level. Lowering the PM 
design level to 18 mg/dscm may not be appropriate based on this minimal 
impact on overall PM emissions.
    Thus, EPA specifically invites comment on whether the final rule 
should establish BTF standard for PM of 35 mg/dscm (or 0.15 lb/ton of 
raw material (dry basis) feed into the kiln).
3. MACT for Mercury
    a. MACT Floor. Mercury emissions from LWAKs are currently 
controlled by the BIF rule, and LWAKs have elected to comply with the 
BIF standard by limiting the feedrate of Hg in the hazardous 
waste.\114\ Thus, the MACT floor is based on hazardous waste feed 
control.
---------------------------------------------------------------------------

    \114\ EPA notes that one LWAK is equipped with a venturi 
scrubber that can provide control of Hg. That kiln, however, is the 
highest Hg-emitting kiln in our database because, EPA believes, it 
burns waste with high levels of Hg.
---------------------------------------------------------------------------

    The LWAK mercury emissions data reflect results from 13 test 
conditions collected from 6 facilities, with a total of 10 kilns being 
tested. The average mercury emissions for the test conditions ranged 
from 0.4 g/dscm to 560 g/dscm.
    To identify the floor level for hazardous waste feed control, the 
Agency determined that sources with Hg emissions at or below the level 
emitted by the median of the best performing 12 percent of sources had 
normalized hazardous waste feedrates (i.e., MTECs) \115\ of Hg of 17 
g/dscm or less. Analysis of all LWAKs using this level of 
hazardous waste feedrate of Hg, or less (i.e., sources having a MTEC of 
17 g/dscm or less), resulted in a MACT floor level of 72 
g/dscm. To meet this standard 99 percent of the time, EPA 
estimates that a source with average emissions variability among runs 
of a test condition would need to design and operate the kiln to meet a 
level of 36 g/dscm.
---------------------------------------------------------------------------

    \115\ MTEC, or maximum theoretical emission concentration, is 
calculated as the feedrate of (Hg) divided by the gas flow rate. It 
is used to normalize feedrates of Hg (and other metals and chlorine) 
across sources with different waste (or fuel) burning capacities.
---------------------------------------------------------------------------

    EPA estimates that approximately 70 percent of LWAKs can meet this 
floor level. The national annualized compliance cost of the remaining 
LWAKs to reduce mercury emissions to the floor level is estimated to be 
$1.6 million for the entire hazardous waste-burning LWAK industry, and 
would reduce mercury emissions by 540 pounds per year or by 86 percent 
from current baseline emissions.
    EPA notes that it considered whether all LWAKs would be likely to 
be able to meet the floor level of 72 g/dscm using control of 
hazardous waste feed for Hg at an MTEC of 17 g/dscm, given 
that Hg emissions also result from Hg in the raw material feed. EPA has 
determined that all LWAKs should be able to meet the floor level using 
the floor control without substituting raw material.
    b. Beyond-The-Floor Considerations. The Agency has considered 
beyond-the-floor (BTF) control for Hg using carbon injection (CI) in 
combustion gas at temperatures below 400 deg.F, coupled with the MACT 
floor level control of Hg in the hazardous waste feed. As discussed for 
CKs, EPA believes that CI can control Hg emissions at or above 90 
percent removal efficiency.
    To identify a BTF level, EPA considered two approaches that would 
result in virtually the same BTF standard--6 g/dscm. Under one 
approach, EPA would apply a 90 percent removal efficiency for CI to the 
floor design level of 36 g/dscm to identify a BTF standard of 
6 g/dscm, which includes a statistically-derived variability 
factor.
    Under a second approach, EPA could account for emissions 
variability by using a conservative CI removal efficiency of 80 percent 
to identify a BTF emission standard of 7.2 g/dscm (based on a 
design floor level of 36 g/dscm). Under this approach, a 
statistically-derived variability factor would not be added.
    EPA invites comment on which approach would be more appropriate for 
identifying a BTF level. EPA, however, is not proposing a BTF standard.
    In conjunction with earlier evaluations, the Agency has evaluated 
the cost and emissions reductions associated with an emission standard 
of 8 g/dscm. Although the BTF levels presented above are 
somewhat different, EPA does not believe that the difference is large 
enough to significantly affect the information presented below.
    One of 11 LWAKs in the database would be able to meet a BTF level 
of 8 g/dscm currently. The national annualized compliance cost 
for the remaining LWAKs to meet the BTF level is estimated to be $4.4 
million for the entire hazardous waste-burning LWAK industry. The BTF 
level would provide an incremental reduction of 60 pounds per year (72 
percent) in Hg emissions nationally beyond that achieved with floor 
controls.
    EPA has considered the costs in relation to emissions reductions 
and the special bioaccumulation potential that Hg poses and has decided 
that the floor level of 72 g/dscm best balances those factors. 
Mercury is one of the more toxic metals known due to its 
bioaccumulation potential and the neurological health effects at low 
concentrations. For further discussion see the mercury benefits 
discussion in Section VII of today's preamble. EPA invites comment, 
however, on whether there are cost-effectiveness or other factors that 
would lead the Agency to promulgate a final rule based on the BTF 
level.
4. Semivolatile Metals
    a. MACT Floor. Emissions of SVM from LWAKs are currently controlled 
under the BIF rule. LWAKs use a combination of hazardous waste feedrate 
control and PM control to comply with those standards. Accordingly, 
MACT floor control is based on hazardous waste feedrate control and PM 
control.
    The LWAK semivolatile metals (SVM) (consisting of cadmium and lead) 
data reflect results from 13 test conditions collected from 6 
facilities, with a total of 10 units being tested. Average emissions of 
the SVM group ranged from 1 g/dscm to 1670 g/dscm. 
Control of semivolatile emissions is associated with PM control (see 
discussion of SVM control for existing cement kilns). All LWAKs are 
equipped with a fabric filter as the air pollution control device, 
although one facility is equipped with a spray dryer, venturi scrubber 
and wet scrubber in addition to the fabric filter.
    The Agency analyzed all available lead and cadmium emissions data 
and determined that sources with emission levels at or below the level 
emitted by

[[Page 17405]]

the median of the best 12 percent of sources employed either: (1) A 
fabric filter with an air-to-cloth ratio of 1.5 acfm/ft \2\ or less 
with a hazardous waste MTEC less than 270,000 g/dscm; or (2) a 
fabric filter and venturi scrubber with an air-to-cloth ratio of 4.2 
acfm/ft \2\ or less with a hazardous waste MTEC less than 54,000 
g/dscm. Analysis of emissions data from all LWAKs using these 
MACT technologies resulted in a floor level of 12 g/dscm.
    EPA notes that raw materials and fossil fuels also contribute to 
LWAK SVM feedrates and emissions. Given that all sources must be able 
to meet the floor level using the floor control, EPA investigated 
whether all LWAKs could meet the floor level employing the MACT floor 
technologies without being forced to substitute raw material. EPA 
preliminary evaluation determined that 25 percent of sources in the SVM 
emissions database had raw material containing Cd and Pb in greater 
concentrations than sources in the expanded MACT pool; thus, these 
sources may not be able to achieve the floor with MACT alone.116 
However, the Agency believes that the data on which this preliminary 
finding is based may not reflect the normal, day-to-day Pb and Cd 
levels in raw material feed.
---------------------------------------------------------------------------

    \116\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
---------------------------------------------------------------------------

    As noted in the earlier section on cement kilns, one approach to 
address this issue (of sources with higher levels of SVM metals in 
their raw materials than sources in the expanded MACT pool and that, 
therefore, cannot meet the floor level using floor control) is to: (1) 
Identify the source with the highest normalized (by MTEC) feedrate of 
metals in raw material; (2) assume the source is also feeding hazardous 
waste with the floor control MTEC level of the metals; and (3) project 
SVM emissions from the source based on combined raw material and 
hazardous waste MTECs using a representative system removal efficiency 
(SRE) from the expanded MACT pool considering an appropriate 
variability factor (e.g., variability of emissions among runs within a 
test condition in the expanded MACT pool). The Agency has not yet 
conducted this type of analysis, but intends to do so in the near 
future. EPA also believes that data reflecting normal, day-to-day 
levels of Pb and Cd in raw materials would be important for this type 
of analysis, and specifically invites commenters to submit such data as 
well as their views on the approach suggested above.
    EPA estimates that 38 percent of LWAKs are currently meeting the 
floor level. The national annualized compliance cost of the remaining 
LWAKs to reduce SVM emissions to the floor level is estimated to be 
$2.1 million for the entire LWAK industry, and would reduce lead and 
cadmium emissions nationally by 0.66 tons per year, or by 97 percent 
from current baseline emissions.
    The Agency is proposing an alternative compliance option for SVMs. 
Since the Agency anticipates the likelihood of development of a multi-
metals continuous emissions monitor (CEM) in the near future, the 
Agency is proposing establishing a higher standard for sources using a 
properly designed and operated multi-metals CEM. This alternative 
compliance option would be based on the minimum detection limit of the 
device, which is estimated to be 60 g/dscm for SVMs combined.
    b. Beyond-The-Floor Considerations. The Agency considered whether 
to propose a more stringent level than the floor of 12 g/dscm. 
EPA has determined that a BTF standard would not be appropriate. Since 
control of semivolatile emissions is associated with PM control, a more 
stringent SVM BTF level would require LWAKs to upgrade to more 
expensive fiberglass bags (e.g., bags backed with teflon membranes) or 
the addition of newly installed FFs with improved performance media. 
Although the engineering costs to comply with a BTF SVM level are 
moderate, the resulting incremental reduction in SVM emissions from the 
floor level is minimal because the floor level already provides 
substantial control by reducing baseline emissions by 97 percent. Thus, 
the Agency believes a SVM BTF standard is not appropriate and is 
proposing a SVM MACT standard of 12 g/dscm for existing LWAKs.
5. Low-Volatility Metals
    a. MACT Floor. Emissions of LVM from LWAKs are also currently 
controlled under the BIF rule. LWAKs use a combination of hazardous 
waste feedrate control and PM control to comply with those standards. 
Accordingly, MACT floor control is based on hazardous waste feedrate 
control and PM control.
    The low volatility metals (LVM) (consisting of arsenic, antimony, 
beryllium, and chromium) data reflect results from 13 test conditions 
collected from 6 facilities, with a total of 10 units being tested. 
Average emissions of the LVM group ranged from 10 g/dscm to 
289 g/dscm. Due to the relatively low volatility of these 
metals, performance of the APCD is the most important factor in 
controlling LVM emissions.
    The Agency analyzed all available LVM emissions data and determined 
that sources with emission levels at or below the level emitted by the 
median of the best 12 percent of sources used a fabric filter with an 
air-to-cloth ratio of 1.8 acfm/ft \2\ or less with a hazardous waste 
MTEC less than 46,000 g/dscm. Analysis of available emissions 
data for all LWAKs employing these controls resulted in a floor 
emission level of 340 g/dscm.
    EPA notes that raw materials and fossil fuels also contribute to 
LWAK LVM feedrates and emissions. Given that all sources must be able 
to meet the floor level using the floor control, EPA investigated 
whether all LWAKs could meet the floor level employing the MACT floor 
technologies without being forced to substitute raw material. EPA's 
preliminary evaluation determined that one of the sources in the LVM 
emissions database had raw material containing LVM in greater 
concentrations than sources in the expanded MACT pool; thus, this 
sources may not be able to achieve the floor with MACT alone.\117\ EPA 
requests comments on addressing this issue.
---------------------------------------------------------------------------

    \117\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
---------------------------------------------------------------------------

    One approach to address this issue (of sources with higher levels 
of LVM metals in their raw materials than sources in the expanded MACT 
pool and that, therefore, cannot meet the floor level using floor 
control) is to: (1) Identify the source with the highest normalized (by 
MTEC) feedrate of metals in raw material; (2) assume the source is also 
feeding hazardous waste with the floor control MTEC level of the 
metals; and (3) project LVM emissions from the source based on combined 
raw material and hazardous waste MTECs using a representative system 
removal efficiency (SRE) from the expanded MACT pool considering an 
appropriate variability factor (e.g., variability of emissions among 
runs within a test condition in the expanded MACT pool). The Agency has 
not yet conducted this type of analysis but intends to do so in the 
near future. EPA also believes that data reflecting normal, day-to-day 
levels of LVM in raw materials would be important for this type of 
analysis and specifically invites commenters to submit such data as 
well as their views on the approach suggested above.
    EPA estimates that 92 percent of LWAKs are currently meeting the 
floor level. The national annualized cost of

[[Page 17406]]

the remaining LWAKs to reduce LVM emissions to the floor level is 
estimated to be $380,000 for the entire hazardous waste-burning LWAK 
industry; this would reduce LVM emissions nationally by 0.011 ton per 
year or by 5 percent from current baseline emissions.
    b. Beyond-The-Floor Considerations. The Agency considered whether 
to propose a more stringent level than the floor of 340 g/
dscm. Since control of low-volatile emissions is associated with PM 
control, a more stringent LVM BTF level would require LWAKs to upgrade 
to more expensive fiberglass bags (e.g., bags backed with teflon 
membranes) or the addition of newly installed FFs with improved 
performance media. Although the engineering costs to comply with a BTF 
LVM level are moderate, the resulting reduction in LVM emissions is 
minimal since LWAK LVM national emissions are estimated to be 0.2 tons 
per year for the entire industry at the floor level. Thus, the Agency 
believes a LVM BTF standard is not appropriate and is proposing a LVM 
MACT standard of 340 g/dscm for existing LWAKs.
6. Hydrochloric Acid and Chlorine
    a. MACT Floor. HCl and Cl2 emissions from LWAKs are currently 
regulated by the BIF rule. Only one LWAK facility currently utilizes a 
venturi scrubber, which is a dedicated control device, designed 
specifically to remove HCl/Cl2 (referred to as total chlorine 
where combined HCl and Cl2 levels are expressed as HCl 
equivalents) from the flue gas.
    The total chlorine emission database reflects results from 13 test 
conditions collected from 6 facilities, with a total of 10 units being 
tested. Average total chlorine emissions range from 13 ppmv to 2080 
ppmv. The Agency analyzed all available total chlorine emissions data 
and determined that sources with emission levels at or below the level 
emitted by the median of the best 12 percent of sources used either: 
(1) Hazardous waste feedrate control of total chlorine with a MTEC less 
than 1.5 g/dscm; or (2) venturi scrubber with hazardous waste MTEC less 
than 14 g/dscm. The analysis of all available emissions data for LWAKs 
using these technologies resulted in a floor emissions level of 2100 
ppmv, which the Agency has identified as the MACT floor level. To meet 
this standard 99 percent of the time, a source with average within test 
condition emission variability would need to be designed and operated 
to achieve an emission level of 1400 ppmv.
    EPA notes that raw materials and fossil fuels also contribute to 
LWAK chlorine feedrates and emissions. Given that all sources must be 
able to meet the floor level using the floor control, EPA investigated 
whether all LWAKs could meet the floor level employing the MACT floor 
technologies without being forced to substitute raw material. EPA 
determined that all LWAKs in the total chlorine emissions database 
would be able to meet the floor level using floor control \118\ without 
switching raw material.
---------------------------------------------------------------------------

    \118\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume III: Selection of Proposed MACT Standards and 
Technologies'', February 1996.
---------------------------------------------------------------------------

    EPA estimates that 85 percent of LWAKs are currently meeting the 
floor level. The national annualized compliance cost of the remaining 
LWAKs to reduce total chlorine emissions to the floor level is 
estimated to be $890,000 for the entire hazardous waste-burning LWAK 
industry; this would reduce total chlorine emissions nationally by 190 
tons per year or 6 percent from current baseline emissions.
    b. Beyond-The-Floor Considerations. The Agency has considered BTF 
controls for improved total chlorine control using a dry scrubber or 
spray tower scrubber. A dry scrubber should achieve a total chlorine 
removal efficiency of 90 percent, and a spray tower scrubber should 
achieve a removal efficiency of 99 percent. Applying the 90 percent 
removal factor (the more conservative of the two removal efficiencies) 
\119\ to the highest test condition in the database resulted in a BTF 
standard of 450 ppmv. To meet this standard 99 percent of the time, EPA 
estimates that a source with average emissions variability (among runs 
within a test condition) would need to meet a design level of 210 ppmv.
---------------------------------------------------------------------------

    \119\ The Agency believes that many, but not all, LWAKs could 
use a dry scrubber without adversely affecting the quality of the 
LWAK dust (which is primarily raw material) for incorporation into 
products or recycling back into the kiln. See discussion in the text 
below.
---------------------------------------------------------------------------

    EPA believes that dry scrubbers or spray tower scrubbers are 
appropriate controls and is proposing a 450 ppmv total chlorine 
emission standard based on these controls. EPA estimates that 38 
percent of LWAKs are currently meeting this BTF level. The national 
annualized compliance cost for the remaining LWAKs to meet this BTF 
level rather than comply with the floor controls is estimated to be 
$5.0 million for the entire hazardous waste-burning LWAK industry. This 
BTF level would provide an incremental reduction of 2200 tons per year 
(80 percent) in total chlorine emissions nationally beyond that 
achieved with the floor controls.
    The Agency believes that both wet and dry scrubbing control 
techniques are applicable to LWAKs for chlorine control. Dry scrubbing 
is being used at some hazardous waste-burning LWAKs. Control efficiency 
and outlet chlorine emissions levels are unclear due to conflicting 
trial burn results, however. One potential problem with the application 
of dry scrubbing to LWAKs is contamination of the captured LWAK dust 
with dry sorbent. This may affect whether captured dust can be recycled 
back into the kiln or incorporated into the final light weight 
aggregate product. The addition of dry scrubbing could force some kilns 
either to add a separate, additional FF dedicated to capturing the dry 
sorbent or dispose of the mixed sorbent and LWAK dust. The Agency 
invites comment on the effectiveness (and implications on dust 
management) of dry scrubbing for control of chlorine in hazardous 
waste-burning LWAKs.
    The Agency also considered an additional BTF level of 25 ppmv for 
LWAKs based on wet scrubbing alone. A further reduction from the 
proposed BTF design level of 210 ppmv (based on dry scrubbing or spray 
tower scrubbing) to 25 ppmv would require all thirteen LWAK sources to 
either install new control equipment, or modify existing control 
equipment. The incremental cost of this enhanced control would be 
moderate to high for each of the individual LWAK sources. Although the 
engineering cost for each facility is moderate to high, the overall 
cost for LWAKs as a group is high since upgrades are required by every 
facility. The Agency believes that the resulting moderate decrease in 
total chlorine emissions may not justify this relatively high 
engineering cost.
    Based on cost-effectiveness considerations, EPA has determined that 
proposing a BTF standard of 450 ppmv is warranted. As discussed 
elsewhere in today's preamble, EPA's risk analysis developed for 
purposes of RCRA shows that the emissions of total chlorine from 
hazardous waste-burning LWAKs could pose significant risks by direct 
inhalation, and these risks would be reduced by BTF controls.\120\ 
Thus, the BTF controls would make separate RCRA standards unnecessary.
---------------------------------------------------------------------------

    \120\ EPA notes that under the BIF regulations, LWAKs are 
currently subject to site-specific, risk-based emissions standards 
for HCl/Cl2. EPA is uncertain why our risk assessment to 
consider RCRA concerns under today's proposed rule shows that 
baseline emissions for some LWAKs can pose significant risk.
---------------------------------------------------------------------------

    Additionally, the Agency requests comments on an alternative option 
to identify the BTF level. Under this

[[Page 17407]]

option the 90 percent reduction in emissions provided by a dry scrubber 
or spray tower scrubber would be applied to the floor level resulting 
from hazardous waste feedrate control of total chlorine--2100 ppmv. 
Thus, at 90 percent control efficiency, the BTF emission standard would 
be 210 ppmv. To comply with this standard 99 percent of the time, a 
source with average within test condition emissions variability would 
need to be designed and operated to meet an emission level of 
approximately 140 ppmv. EPA invites comment on whether this option is 
more appropriate to establish the BTF level than applying the BTF 
percent reduction to the test condition in the database with the 
highest emissions.
    As discussed above, EPA believes that a dry scrubber or spray tower 
scrubber (in conjunction with the levels achieved using MACT floor 
controls) are appropriate alternative controls. EPA estimates that 38 
percent of LWAKs are currently meeting this alternative BTF level of 
210 ppmv. EPA estimates that this BTF level would provide a further 
incremental reduction in total chlorine emissions nationally beyond 
that achieved with the proposed BTF standard of 450 ppmv. EPA invites 
comment on this alternative approach to identify the BTF level.
7. Carbon Monoxide and Hydrocarbons
    The Agency is proposing to use carbon monoxide (CO) and 
hydrocarbons (HC) as surrogates for non-D/F organic HAPs.\121\
---------------------------------------------------------------------------

    \121\ This is in addition to controlling PM as a surrogate for 
(condensed) semivolatile HAPs.
---------------------------------------------------------------------------

    a. MACT Floor.
    i. Carbon Monoxide. The BIF rule currently limits CO emissions from 
LWAKs to 100 ppmv on an hourly rolling average (HRA). See 
Sec. 266.104(b). However, the BIF rule provides an alternative standard 
that allows higher CO levels if HC levels are less than 20 ppmv.
    LWAKs generally have low CO levels (i.e., less than 100 ppmv HRA) 
achieved by operating under good combustion practices. Good combustion 
practices include techniques such as thorough fuel, air, and waste 
mixing; adequate excess oxygen; maintenance of adequate combustion 
temperature; and blending of waste fuels to minimize combustion 
perturbations. Accordingly, operating under good combustion practices 
is identified as the floor control.
    Given that 10 of 12 LWAKs for which EPA has CO emissions data have 
maximum hourly rolling averages for the test condition of less than 100 
ppmv, EPA believes it is reasonable and appropriate to identify the 
floor level as the BIF limit of 100 ppmv. Two LWAKs have CO levels 
exceeding the 100 ppmv level, however, and these higher levels (i.e., 
190 ppmv and 1900 ppmv) are allowed under the BIF rule. EPA is not sure 
whether these elevated CO levels were caused by operating under poor 
combustion conditions, or by trace levels of organics desorbing from 
the raw materials.
    If the CO were caused by organics desorbing from raw material, EPA 
would consider this situation analogous to CKs that do not have a by-
pass duct (and thus stack emissions are affected by organics desorbed 
from raw material). Accordingly, such LWAKs would be exempt from the CO 
limit (and would be subject to a HC limit of 20 ppmv). (In this 
situation, floor control (i.e., good combustion practices) could not be 
used to meet the floor level.) EPA invites comment on how to 
distinguish between LWAKs that have elevated CO levels because of poor 
combustion (and that should be subject to the 100 ppmv floor level) and 
LWAKs that have elevated CO levels because of desorption of organics 
from raw material (and that should be exempt from the 100 ppmv floor 
level). If an effective approach to distinguish between these 
situations is developed, the final rule could distinguish among LWAKs 
based on those high levels of organics in raw material versus those 
with low levels.
    EPA estimates that over 80 percent of LWAKs are currently meeting 
the proposed standard. The national annualized compliance cost of the 
remaining LWAKs to reduce carbon monoxide emissions to the floor level 
\122\ is estimated to be $1.4 million for the entire LWAK industry; 
this would reduce carbon monoxide emissions nationally by 600 tons per 
year, or 81 percent from current baseline emissions.
---------------------------------------------------------------------------

    \122\ EPA assumed that the LWAK with CO levels of 1900 ppmv 
would need to install an afterburner to meet the floor level. EPA 
acknowledges that this is inappropriate because all sources must be 
able to meet the floor level using floor control--good combustion 
practices. As discussed in the text, EPA invites comment on how to 
identify appropriate MACT floor levels for sources that may have 
elevated CO levels due to desorption of organics from raw material.
---------------------------------------------------------------------------

    ii. Hydrocarbons. As discussed above, the BIF rule limits HC levels 
to 20 ppmv HRA when CO exceeds 100 ppmv HRA. As with CO, floor control 
is operating under good combustion practices. EPA believes it is 
appropriate to establish the floor level at the lower of the BIF 
emission limit or the levels that sources actually achieved. An 
analysis of the available HC data determined that sources with emission 
levels at or below the level emitted by the median of the best 12 
percent of sources used good combustion practices as the control 
technology. The analysis of all available emissions data for LWAKs 
believed to be using good combustion practices resulted in a floor 
emissions level of 14 ppmv.\123\
---------------------------------------------------------------------------

    \123\ EPA notes that one of seven LWAKs in the HC database had 
substantially higher test condition maximum HC levels (i.e., 13 ppmv 
HRA) than the other sources (i.e., 6 to 8 ppmv HRA). As discussed in 
the text above for CO, it is not clear whether the elevated HC 
levels were caused by operating under poor combustion conditions or 
desorption of organics from raw material. EPA invites comment on how 
to address this situation.
---------------------------------------------------------------------------

    EPA estimates that 86 percent of LWAKs are currently meeting the 
floor HC level. The national annualized compliance cost of the 
remaining LWAKs to reduce hydrocarbon emissions to the floor level is 
estimated to be $760,000 for the entire LWAK industry; this would 
reduce hydrocarbon emissions nationally by 14 tons per year, or 31 
percent from current baseline emissions.
    b. Beyond-The-Floor Considerations. EPA considered BTF levels for 
CO of 50 ppmv and for HC of 6 ppmv. Control of organic HAP emissions 
would require the use of a combustion gas afterburner. Addition of an 
afterburner to a LWAK would be expensive due to the requirement of a 
large amount of auxiliary fuel to reheat the kiln exit flue gas to 
temperatures required for organics burnout. Preliminary estimates 
suggest that going beyond-the-floor for CO and HC would more than 
double the national costs of complying with the proposed rule. EPA 
believes that a BTF standard is not appropriate.
    EPA estimates that 29 percent of LWAKs are currently meeting the 
BTF level of 6 ppmv for HC and that 46 percent of LWAKs are currently 
meeting the BTF levels of 50 ppmv for CO. The Agency has determined 
that selecting these BTF levels is not appropriate. Therefore, the 
Agency is proposing a MACT standard for hydrocarbons of 14 ppmv HRA and 
for carbon monoxide of 100 ppmv HRA.
8. MACT Floor Cost Impacts
    The total national annualized compliance costs for existing LWAKs 
to meet all the MACT floor levels are estimated to be $3 million with 
the cost per kiln averaging $390,000. These total compliance costs 
equate to $39 per ton of hazardous waste burned. EPA estimates that one 
LWAK facility may cease burning hazardous waste due to the compliance 
costs associated at the floor.

[[Page 17408]]

    The Agency is proposing to go beyond-the-floor for three pollutants 
for existing LWAKs: dioxin/furans, mercury, and total chlorine. The 
total national annualized compliance costs to meet the dioxin/furan, 
mercury and total chlorine BTF standards in addition to the MACT floor 
standards for the remaining HAPs are estimated to be $4 million with 
the cost per kiln averaging $670,000. These total compliance costs 
increase the cost per ton of hazardous waste burned to $56. EPA 
estimated that one LWAK facility may cease burning hazardous waste due 
to the compliance costs associated with this suite of floor and BTF 
standards.
B. MACT for New Sources
    This section summarizes EPA's rationale for establishing MACT for 
new LWAKs for each HAP, HAP surrogate, or HAP group. Table V.5.B.1 
summarizes the proposed MACT standards for new LWAKs, which were 
determined using the analytical process described in Part Three, 
Section VII and in ``Draft Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and Technologies''.

         Table IV.5.B.1.--Proposed Emission Levels for New LWAKs        
------------------------------------------------------------------------
           HAP or HAP Surrogate                Proposed Standards \1\   
------------------------------------------------------------------------
Dioxin/furans.............................  0.20 ng/dscm TEQ.           
Particulate Matter........................  0.030 gr/dscf (69 mg/dscm). 
Mercury...................................  72 g/dscm.         
SVM [Cd, Pb]..............................  5.2 g/dscm \2\.    
LVM [As, Be, Cr, Sb]......................  55 g/dscm \3\.     
HCl + Cl2.................................  62 ppmv.                    
CO........................................  100 ppmv.                   
HC........................................  14 ppmv.                    
------------------------------------------------------------------------
\1\  All emission levels are corrected to 7 percent O2.                 
\2\  An alternative standard of 60 g/dscm would apply if the   
  source elects to document compliance using a multi-metals CEM.        
\3\  An alternative standard of 80 g/dscm would apply if the   
  source elects to document compliance using a multi-metals CEM.        

1. MACT New for Dioxin/Furan
    a. MACT NEW Floor. EPA used the Agency's data on the performance of 
D/F control technology to identify MACT floor controls and the floor 
level for new facilities. The MACT floor level for D/F emissions from 
LWAKs is 0.20 ng/dscm (TEQ) or (temperature at the PM control device 
not to exceed) 418  deg.F.
    b. Beyond-The-Floor Considerations. The BTF considerations for new 
LWAKs were the same as for CKs. Therefore, EPA is proposing a BTF 
standard for new LWAKs of 0.20 ng/dscm (TEQ) for the same reasons 
applicable to CKs.
2. MACT New for Particulate Matter
    a. MACT New Floor. EPA's analysis of available PM data shows that 
the single best APCD for controlling particulate emissions is a fabric 
filter with an air-to-cloth ratio less than 1.5 acfm/ft \2\ which 
represents MACT technology for new sources. An evaluation of all 
sources employing this technology shows that this technology can 
consistently achieve a PM emission of 0.054 gr/dscf.
    b. Beyond-The-Floor Considerations. For the same reasons as 
discussed for existing LWAKs, the Agency is proposing a lower BTF 
standard for new LWAKs. Therefore, the Agency is proposing the MACT 
standard of 69 mg/dscm (0.03 gr/dscf) for new LWAKs.
    As discussed above for existing LWAKs, EPA specifically invites 
comment on whether the final rule should establish an alternative BTF 
standard for PM of 35 mg/dscm (or 0.15 lb/ton of raw material (dry 
basis) feed into the kiln).
3. MACT New for Mercury
    a. MACT New Floor. The MACT new floor analysis is the same as 
existing sources because the expanded pools for each, based on the 
single best performing source, are identical. As discussed earlier, 
LWAKs control their mercury input (and therefore much of their 
emissions) through the control of the mercury content in the hazardous 
waste. The Agency is defining the MACT floor technology as feedrate 
control with a hazardous waste MTEC less than 17 g/dscm based 
on performance of the single best performing source. Analysis of all 
existing LWAK sources using this hazardous feedrate control resulted in 
a MACT floor level of 72 g/dscm.
    b. Beyond-the-Floor Consideration. The Agency is considering the 
same two BTF options for new LWAKs as discussed for existing sources--
Option 1 is 6 g/dscm, and Option 2 is 7.2 g/dscm. The 
Option 1 mercury BTF level of 6 g/dscm is achievable based on 
the use of some degree of hazardous waste feedrate control and/or add-
on mercury control with injection of activated carbon, assuming a 90 
percent reduction. The Option 2 level of 7.2 g/dscm represents 
an achievable level based on both achievement of floor levels and use 
of carbon injection, assuming conservative 80 percent reduction.
    Therefore, EPA is proposing a mercury MACT standard of 72 
g/dscm for existing LWAKs and requesting comments on possible 
BTF standard of 6 g/dscm and 7.2 g/dscm.
4. MACT New for Semivolatile Metals
    a. MACT New Floor. EPA characterized the single best performing 
source with the lowest SVM emissions and determined that the best 
performing source used a fabric filter with an air-to-cloth ratio of 
1.5 acfm/ft2 or less for a kiln system with a hazardous waste (HW) 
MTEC of 270,000 g/dscm or less. Analysis of all sources using 
this technology or better (i.e., expanded MACT pool of facilities) 
resulted in a floor level of 5.2 g/dscm for new LWAKs.
    The Agency recognizes that 5.2 g/dscm is a low floor level 
and is concerned about potential problems in its approach to setting 
the MACT floor level. The expanded MACT pool included only one other 
test condition besides the single best source, and EPA is concerned 
that this low data set resulted in a low floor level. In addition, EPA 
is concerned that the single best performing source may have low SVM 
feedrates in the raw material, which could result in a floor level that 
is unachievable. EPA invites comment on how to address these potential 
issues.
    The Agency is proposing an alternative compliance option for SVMs. 
Since the Agency anticipates the likelihood of development of a multi-
metals continuous emissions monitor (CEM) in the near future, the 
Agency is proposing establishing a higher standard for sources using a 
properly designed and operated multi-metals CEM. This alternative 
compliance option would be based on the minimum detection limit of the 
device which is estimated to be 60 g/dscm for SVMs combined.
    b. Beyond-the-Floor Considerations. EPA has determined that 
proposing a BTF standard is not warranted for the same reasons that a 
more stringent level was not proposed for existing sources. Therefore, 
the Agency is proposing a semivolatile metals MACT standard of 5.2 
g/dscm for new LWAKs.
5. MACT New for Low-Volatile Metals
    a. MACT New Floor. EPA characterized the best particulate control 
device and identified the floor technology as a fabric filter with an 
air-to-cloth ratio of 1.3 acfm/ft2 or less with a hazardous waste 
(HW) MTEC less than 37,000 g/dscm. Analysis of all existing 
LWAK sources employing either of these technologies resulted in a floor 
emissions level of 55 g/dscm for new LWAKs.
    The Agency is proposing an alternative compliance option for LVMs. 
Since the Agency anticipates the likelihood of development of a multi-
metals continuous emissions monitor

[[Page 17409]]

(CEM) in the near future, the Agency is proposing establishing a higher 
standard for new sources using a properly designed and operated multi-
metals CEM. This alternative compliance option would be based on the 
minimum detection limit of the device which is estimated to be 80 
g/dscm for these LVM metals combined.
    b. Beyond-the-Floor Considerations. EPA has determined that 
proposing a BTF standard is not warranted for the same reasons that a 
more stringent level was not proposed for existing sources. Therefore, 
the Agency is proposing a low-volatile metals MACT standard of 55 
g/dscm for new LWAKs.
6. MACT New for Hydrochloric Acid and Chlorine
    a. MACT New Floor. EPA characterized the single best performing 
source with the lowest HCl/Cl2 (total chlorine) emissions and 
determined that the best performing source used a venturi scrubber with 
a hazardous waste (HW) MTEC of 14 g/dscm or less. Analysis of all 
sources using this technology or better (i.e., expanded MACT pool of 
facilities) resulted in a floor level of 62 ppmv for new LWAKs.
    b. Beyond-the-Floor Considerations. The MACT floor is characterized 
by a technology that is able to achieve a 99 percent removal 
efficiency. A BTF level is not warranted because the floor level is 
based on a technology that is able to achieve the highest removal 
efficiency for HCl/Cl2. Therefore, the Agency is proposing a HCl/
Cl2 MACT standard of 62 ppmv for new LWAKs.
7. MACT New for Carbon Monoxide and Hydrocarbons
    a. MACT New Floor. The Agency believes that control of non-dioxin 
organic emissions can be achieved by establishing emissions limits on 
hydrocarbons and carbon monoxide. As discussed earlier for existing 
LWAKs, the Agency is proposing a MACT standard of 14 ppmv for HC and of 
100 ppmv for CO, based on floor levels
    b. Beyond-the-Floor Considerations. EPA considered control for 
organic HAP emissions based on the use of a combustion gas afterburner. 
Even though EPA believes that BTF levels for CO of 50 ppmv and for HC 
of 6 ppmv are achievable with an afterburner, using these values for a 
BTF standard is not appropriate and is not warranted at this time (see 
discussion for existing LWAKs). Therefore, EPA is proposing a MACT 
standard of 14 ppmv for HC and of 100 ppmv for CO for new LWAKs.
8. MACT New Cost Impacts
    A detailed discussion of the costs and economic impacts for new 
LWAKs is presented in Part Seven of today's proposal and ``Regulatory 
Impact Assessment for Proposed Hazardous Waste Combustion MACT 
Standards''.
C. Evaluation of Protectiveness
    In order to satisfy the Agency's mandate under the Resource 
Conservation and Recovery Act to establish standards for facilities 
that manage hazardous wastes and issue permits that are protective of 
human health and the environment, the Agency conducted an analysis to 
assess the extent to which potential risks from current emissions would 
be reduced through implementation of MACT standards. The analysis 
conducted for hazardous waste-burning LWAKs is similar to the one 
described above for hazardous waste incinerators and cement kilns. The 
procedures used in the Agency's risk analyses are discussed in detail 
in the background document for today's proposal.124 In evaluating 
the MACT standards, the Agency used the design value which is the value 
the Agency expects a source would have to design to in order to be 
assured of meeting the standard on a daily basis and hence is always a 
lower value than the actual standard for all HAPs controlled by a 
variable control technology.125
---------------------------------------------------------------------------

    \124\ ``Risk Assessment Support to the Development of Technical 
Standards for Emissions from Combustion Units Burning Hazardous 
Wastes: Background Information Document'', February 20, 1996.
    \125\ For the semi-volatile and low volatility metals 
categories, the Agency assumed the source could emit up to the 
design value for each metal in the category for the purpose of 
assessing protectiveness.
---------------------------------------------------------------------------

    The risk results for hazardous waste-burning lightweight aggregate 
kilns are summarized in Table V.5.C.1 for cancer effects and Table 
V.5.C.2 for non-cancer effects for the populations of greatest 
interest, namely subsistence farmers, subsistence fishers, recreational 
anglers, and home gardeners. The results are expressed as a range 
representing the variation in exposures across the example facilities 
(and example waterbodies for surface water pathways) for the high-end 
and central tendency exposure characterizations across the exposure 
scenarios of concern. For example, because dioxins bioaccumulate in 
both meat and fish, the subsistence farmer and subsistence fisher 
scenarios are used to determine the range.126
---------------------------------------------------------------------------

    \126\ For the semi-volatile and low volatility metals 
categories, the inhalation MEI scenarios are also used. For hydrogen 
chloride and chlorine (Cl2) only the inhalation MEI scenarios are 
used.

              Table V.5.C.1.--Individual Cancer Risk Estimates for Lightweight Aggregate Kilns \1\              
----------------------------------------------------------------------------------------------------------------
                                           Dioxins            Semi-volatile metals \2\   Low volatile metals \3\
----------------------------------------------------------------------------------------------------------------
                                                Existing Sources                                                
                                                                                                                
----------------------------------------------------------------------------------------------------------------
Baseline........................  2E-9 to 4E-7.............  1E-8 to 5E-7.............  9E-10 to 4E-7.          
Floor...........................  1E-8 to 2E-6 \4\.........  1E-8 to 6E-8.............  5E-7 to 1E-5.           
BTF.............................  1E-8 to 2E-6 \5\.........  .........................  ........................
                                                                                                                
----------------------------------------------------------------------------------------------------------------
                                                   New Sources                                                  
                                                                                                                
----------------------------------------------------------------------------------------------------------------
Floor...........................  1E-8 to 2E-6\4\..........  6E-9 to 3E-8.............  7E-8 to 2E-6.           
BTF.............................  1E-8 to 2E-6\5\..........  .........................  ........................
CEM Option \6\..................  .........................  6E-8 to 3E-7.............  2E-7 to 5E-6.           
----------------------------------------------------------------------------------------------------------------
\1\ Lifetime excess cancer risk.                                                                                
\2\ Carcinogenic metal: cadmium.                                                                                
\3\ Carcinogenic metals: arsenic, beryllium, and chromium (VI).                                                 
\4\ Based on 0.2 ng/dscm TEQ as both a central tendency and high-end estimate.                                  
\5\ Based on 0.20 ng/dscm TEQ.                                                                                  
\6\ Based on SVM standard of 60 g/dscm and LVM standard of 80 g/dscm (applicable only if the  
  source elects to document compliance using a multimetals CEM).)                                               


Federal Register / Vol. 61, No. 77 / Friday, April 19, 1996 / 
Proposed Rules

[[Page 17410]]



                                 Table V.5.C.2--Individual Non-Cancer Risk Estimates for Lightweight Aggregate Kilns \1\                                
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                       Semi-volatile  metals \2\     Low volatile  metals \3\        Hydrogen  chloride                Chlorine         
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Existing Sources                                                                    
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline...........................  <0.001 to 0.006.............  <0.001 to 0.007............  0.1 to 4...................  0.03 to 0.3.               
Floor..............................  <0.001......................  <0.001 to 0.08.............  0.8 to 1\4\................  4 to 7\5\.                 
BTF................................  ............................  ...........................  0.1 to 0.2\4\..............  0.6 to 1\5\.               
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       New Sources                                                                      
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
Floor..............................  <0.001......................  <0.001 to 0.01.............  0.02 to 0.04\4\............  0.1 to 0.2\5\              
BTF................................  ............................  ...........................  0.01 to 0.02\4\............  0.07 to 0.1\5\             
CEM Option \6\.....................  <0.001 to 0.001.............  <0.001 to 0.03.............  ...........................  ...........................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Hazard quotient.                                                                                                                                    
\2\ Cadmium and lead.                                                                                                                                   
\3\ Antimony, arsenic, beryllium, and chromium.                                                                                                         
\4\ HCl + Cl2 assuming 100 percent HCl.                                                                                                                 
\5\ HCl + Cl2 assuming 10 percent Cl2.                                                                                                                  
\6\ Based on SVM standard of 60 g/dscm and LVM standard of 80 g/dscm (applicable only if the source elects to document compliance     
  using a multi-metals CEM).                                                                                                                            

    The risk analysis indicates that for the semi-volatile and low 
volatility metals categories, the MACT standards for lightweight 
aggregate kilns are protective at the floor for both existing and new 
sources. The analysis indicates that the CEM compliance option for new 
sources is also protective. The analysis also indicates that for 
dioxins, both the floor levels and the proposed beyond the floor 
standards are protective. The analysis also indicates that for hydrogen 
chloride and chlorine (Cl2), the proposed beyond-the-floor 
standards for existing sources, rather than the floor levels, are 
protective.

VI. Achievability of the Floor Levels

    As discussed in sections III, IV, and V above, the MACT floor 
levels were selected for each source category by identifying the best 
performing sources for each individual HAP or HAP surrogate. This is 
the approach typically used by the Agency in establishing MACT 
standards.
    Nonetheless, the Agency recognizes that this approach raises the 
question of whether the selected floor levels will be achievable 
simultaneously.
    An alternative approach that would ensure simultaneous 
achievability of the floor levels would be to identify the best 
performing sources for a particular HAP or HAP surrogate (e.g., D/F or 
PM) and to consider emissions only from those sources \127\ to 
establish floor levels for the other HAPs or HAP surrogates. EPA
---------------------------------------------------------------------------

    \127\ Another option would be to consider emissions from other 
sources that employ equivalent or better control for the other HAPs 
or HAP surrogates. has not used this approach because it would 
result in establishing unreasonably high floor levels for most HAPs 
or HAP surrogates that arbitrarily reflect the control devices (and 
emission levels) that happen to be used by sources that are 
performing best solely for the selected, critical HAP or HAP 
surrogate (e.g., D/F or PM).
---------------------------------------------------------------------------

    To address concerns relating to the simultaneous achievability of 
the proposed standards, which are a combination of floor and BTF 
emissions levels, the Agency investigated whether sources could achieve 
the proposed standards without making any upgrades to existing 
equipment. It is important to note that, under the current approach 
used by the agency in establishing MACT standards (i.e. the HAP by HAP 
approach--utilizing the highest emitting source in the expanded MACT 
pool), approximately 5 to 8 percent of the facilities currently 
operating will meet all of the proposed standards. Furthermore, subject 
to the data caveats noted for certain HAPs and source categories (which 
the Agency believes can be resolved properly), it is the opinion of the 
Agency that 100 percent of the facilities who use MACT floor and 
beyond-the-floor technologies can meet all of the proposed standards 
simultaneously.
    Specific information and data pertaining to the analysis of 
simultaneous achievability can be found in ``Regulatory Impact 
Assessment for Proposed Hazardous Waste Combustion MACT Standards''.

VII. Comparison of the Proposed Emission Standards With Emission 
Standards for Other Combustion Devices

    Although not explicitly part of the MACT standard setting process, 
EPA believes, for perspective, it is appropriate to compare the 
proposed emissions standards to those of other waste-burning devices 
and similar devices. (In some cases, such a comparison may show that a 
particular technology or level of performance is demonstrated as well.) 
The standards used for comparison have either been proposed by EPA or 
are guidelines promulgated by the European Union (EU). The standards 
for these various type of devices will be different for reasons 
including: (1) Different statutory authorities and requirements; (2) 
different levels of emission control for existing sources; and (3) 
different potential to emit high levels of specific HAPs. Nonetheless, 
EPA believes a comparison of standards is instructive.
    Tables VII.1 and VII.2 contain the standards for municipal waste 
combustors (MWCs), medical waste incinerators (MWIs), EU hazardous 
waste combustors, and the standards proposed here for existing and new 
facilities, respectively.

[[Page 17411]]



                                               Table VII.1.--Comparison of Standards for Existing Sources                                               
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Proposed HW     Proposed HW cement                    
                                      Large MWCs         Proposed MWIs       EU HWCs (\1\)       incinerators            kilns         Proposed HW LWAKs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dioxin/Furan: ng/dscm TEQ and/or  30 Total (or 15 if  1.9 TEQ or 80       0.19 TEQ..........                                                            
 Total congeners.                  testing less        Total.                                                                                           
                                   frequent).                                                                                                           
(2)0.20 TEQ.                                                                                                                                            
PM, mg/dscm.....................  27................  30................  13 24-hr avg......                                                            
                                                                          13-39 30-min avg                                                              
                                                                           (\2\).                                                                       
(2) 69 2-hr avg                                                                                                                                         
Hg, g/dscm.............  80 or 85% Reduct..  470 or 85% Reduct.  130...............                                                            
(1) 50 10-hr avg                  72 10-hr avg......                                                                                                    
SVM, g/dscm............  Cd: 40............  Cd: 50............  Cd: 65............  270...............  57................  12.               
                                  Pb: 49............  Pb: 100...........  Tl: 65............                                                            
                                                                          Pb: 130 (\3\).....                                                            
LVM, g/dscm............  none..............  none..............  1170 (\3\)........  210...............  130...............  340.              
CO, ppmv........................  50 to 250 4 to 24   50 12-hr avg......  52, 24 hr avg.....  100 1 hr avg......  Wet and Long, Dry   100 1 hr avg.     
                                   hr avg.                                104, 30 min avg                          Kilns None.                          
                                                                           (\4\).                                 Kilns with By-pass                    
                                                                          156, 10 min avg                          100 in by-pass                       
                                                                           (\4\).                                  duct (or HC                          
                                                                                                                   cannot exceed                        
                                                                                                                   6.7) 1 hr avg.                       
HC, ppmv........................  None..............  None..............  8, 24 hr avg......  12 1 hr avg.......  Wet and Long, Dry   14 1 hr avg.      
                                                                          8-16, 30 min avg                         Kilns 20 in main                     
                                                                           (\2\).                                  stack 1 hr avg.                      
                                                                                                                  Kilns with By-pass                    
                                                                                                                   6.7 in by-pass                       
                                                                                                                   (or CO cannot                        
                                                                                                                   exceed 100) 1 hr                     
                                                                                                                   avg.                                 
HCl and Cl2, ppmv as HCl          31 or 95% Reduct..  42 or 97% Reduct..  8, 24-hr avg......  280...............  630...............  450.              
 equivalents (\5\).                                                       8-48, 30 min avg                                                              
                                                                           (\2\).                                                                       
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: \1\ The EU HWC guidelines have been corrected from the European basis of 11% O2 and 0 deg.C to the US basis of 7% O2 and 20 deg.C. Both are      
  expressed on dry emissions.                                                                                                                           
\2\ The EU HWC PM, HC, and HCl guidelines are based either 97 % compliance with the lower number or 100% compliance with the higher number on a 30-     
  minute average over a year.                                                                                                                           
\3\ The EU LVM guideline is 1300 g/dscm and includes Sb, As, Pb, Cr, Co, Cu, Mn, Ni, V, Sn. If all metals are emitted equally, their           
  contribution is 130 2g/dscm. Pb, a SVM, was subtracted from this group, resulting in the 1170 g/dscm level.                                  
\4\ The EU HWC CO guideline is based on either 95% compliance with the 156 ppm level on a 10 minute average or 100% compliance with the 104 ppm level on
  a 30-minute average in any day.                                                                                                                       
\5\ The proposed MWC and MWI and the EU MWC guideline are for HCl only.                                                                                 


                                                  Table VII.2.--Comparison of Standards for New Sources                                                 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Proposed HW     Proposed HW cement                    
                                      Large MWCs             MWIs             EU HWCs \1\        incinerators            kilns         Proposed HW LWAKs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dioxin/Furan: ng/dscm TEQ, and/   13 Total (or 7 if   1.9 TEQ or 80       0.19 TEQ..........                                                            
 or Total congeners                testing less        Total                                                                                            
                                   frequent)                                                                                                            
(2)0.20                                                                                                                                                 
PM, mg/dscm.....................  24................  30................  13 24-hr avg......                                                            
                                                                          13-39 30-min avg                                                              
                                                                           \2\.                                                                         
(2)69 2-hr avg                                                                                                                                          
Hg, g/dscm.............  80 or 85% Reduct..  470 or 85% Reduct.  6.5...............                                                            
(1)50 10-hr avg                   72 10-hr avg......                                                                                                    
SVM, g/dscm............  Cd: 20............  Cd: 50............  Cd: 3.25..........  62................  55................  5.2.              
                                  Pb: 20............  Pb: 100...........  Tl: 3.25..........                                                            
                                                                          Pb: 65 \3\........                                                            
LVM, g/dscm............  None..............  None..............  585 \3\...........  60................  44................  55.               
CO, ppmv........................  50 to 150 4 to 24   50 12-hr avg        52, 24-hr avg.....  100 1 hr avg......  Wet and Long, Dry   100 1 hr avg.     
                                   hr avg.                                104, 30 min avg                          Kilns None                           
                                                                           \4\.                                   Kilns with By-pass                    
                                                                          156, 10 min avg                          100 in by-pass                       
                                                                           \4\.                                    duct (or HC                          
                                                                                                                   cannot exceed                        
                                                                                                                   6.7) 1 hr avg.                       

[[Page 17412]]

                                                                                                                                                        
HC..............................  None..............  None..............  8, 24 hr avg......  12 1 hr avg.......  Wet and Long, Dry   14 1 hr avg.      
                                                                          8-16, 30 min avg                         Kilns                                
                                                                           \2\.                                   20 in main stack 1                    
                                                                                                                   hr avg                               
                                                                                                                  Kilns with By-pass                    
                                                                                                                   6.7 in by-pass                       
                                                                                                                   (or CO cannot                        
                                                                                                                   exceed 100) 1 hr                     
                                                                                                                   avg                                  
HCl and Cl2, ppmv as HCl          25 or 95% Reduct..  42 or 97% Reduct..  8, 24-hr avg......                                                            
 equivalents \5\                                                          8-48, 30 min avg                                                              
                                                                           \2\                                                                          
(1)67                             62.                                                                                                                   
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:                                                                                                                                                  
\1\ The EU HWC guidelines have been corrected from the European basis of 11% O2 and 0 deg.C to the US basis of 7% O2 and 20 deg.C. Both are expressed on
  dry emissions.                                                                                                                                        
\2\ The EU HWC PM, HC, and HCl guidelines are based either 97 % compliance with the lower number or 100% compliance with the higher number on a 30-     
  minute average over a year.                                                                                                                           
\3\ The EU LVM guideline is 650 g/dscm and includes Sb, As, Pb, Cr, Co, Cu, Mn, Ni, V, Sn. If all metals are emitted equally, their            
  contribution to the guideline is 65 g/dscm. Pb, a SVM, was subtracted from this group, resulting in the 585 g/dscm level.           
\4\ The EU HWC CO guideline is based on either 95% compliance with the 156 ppm level on a 10 minute average or 100% compliance with the 104 ppm level on
  a 30-minute average in any day.                                                                                                                       
\5\ The proposed MWC and MWI standards and the EU HWC guideline are for HCl only.                                                                       



VIII. Alternative Floor (12 Percent) Option Results and Option to 
Address Variability

    As described in Part 3, Section 5, EPA considered another approach 
(termed the ``12 percent approach'') to establishing the MACT floor. In 
this approach, the Agency selected an emissions floor level based on 
the average emissions of the 12 percent MACT pool and the average 
variability within the pool. As in the other approaches, the standards 
are based on HW MTEC where appropriate, 3-run averages, and a 99th 
percentile confidence interval.
    Through the evaluation of the emissions database using this 12 
percent approach, it was determined that various sources equipped with 
floor controls would be unable to meet the floor emission limits. EPA 
believes that, if this approach is used to determine emission 
standards, a situation would be created that is arguably inconsistent 
with the spirit of the Act. Furthermore, it could subject the regulated 
community to an undue burden--one in which some facilities in the MACT 
floor pool must add control equipment in addition to the recognized 
floor controls in order to meet the floor levels. It could also place 
EPA in a position of defending a floor-based standard in which the 
identified floor control technology does not clearly achieve the 
specified floor emissions levels for all of the facilities in the MACT 
floor pool. Although we are inclined not to use this evaluation method 
due to these concerns, we invite comment on this approach versus other 
MACT floor approaches.
    Additionally, information regarding the level of protection these 
standards provide can be found in U.S. EPA, ``Risk Assessment Support 
to the Development of Technical Standards for Emissions from Combustion 
Units Burning Hazardous Wastes: Background Information Document'', 
February 20, 1996.

A. Summary of Results of 12 Percent Analysis

    Table VIII.1 shows the results of the 12 percent floor analysis for 
existing sources:

                                                Table VIII.1.--12 Percent Approach Mact Floor Results\1\                                                
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Incinerators                  Cement kilns                    LWA kilns         
                 HAP                           Units          ------------------------------------------------------------------------------------------
                                                                            Stnd                          Stnd                          Stnd.           
--------------------------------------------------------------------------------------------------------------------------------------------------------
D/F.................................  g TEQ.........  0.25.........................  0.23........................  0.23.                       
Hg..................................  g/dscm........  13...........................  32..........................  32.                         
HCl/Cl2.............................  ppmv...................  23...........................  25..........................  1800.                       
SVM.................................  g/dscm........  53...........................  240.........................  61.                         
LVM.................................  g/dscm........  61...........................  46..........................  57.                         
PM..................................  gr/dscf................  0.024........................  0.03........................  0.012.                      
CO..................................  ppmv...................  100..........................  n/a.........................  100.                        
HC..................................  ppmv...................  12...........................  Main \2\:20 by pass \3\:6.7   14.                         
                                                                                               (or CO 100).                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ All emissions levels are corrected to 7 percent O2.                                                                                                 
\2\ Applicable only to long wet and dry process cement kilns (i.e., not applicable to preheater and/or precalciner kilns).                              
\3\ Emissions standards applicable only for cement kilns configured with a by-pass duct (typically preheater and/or precalciner kilns). Sources must    
  comply with either the HC or CO standard in the by-pass stack.                                                                                        

    Table VIII.2 shows the results of the 12 percent approach 
considering BTF analyses for select HAPs for existing sources:

[[Page 17413]]



                                                    Table VIII.2.--12 Percent Approach BTF Option\1\                                                    
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Incinerators                  Cement kilns                    LWA kilns         
                 HAP                           Units          ------------------------------------------------------------------------------------------
                                                                            Stnd                          Stnd                          Stnd            
--------------------------------------------------------------------------------------------------------------------------------------------------------
D/F.................................  g TEQ.........  0.25.........................  0.23........................  0.23.                       
Hg..................................                                                                                                                    
Hg..................................  g/dscm........  13...........................  8...........................  8.                          
HCl/Cl2.............................  ppmv...................  23...........................  25..........................  67.                         
SVM.................................  g/dscm........  53...........................  240.........................  61.                         
LVM.................................  g/dscm........  61...........................  46..........................  57.                         
PM..................................  gr/dscf................  0.024........................  0.03........................  0.012.                      
CO..................................  ppmv...................  100..........................  n/a.........................  100.                        
HC..................................  ppmv...................  12...........................  Main \2\:20 bypass \3\ :6.7   14.                         
                                                                                               (or CO 100).                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ All emissions are corrected to 7 percent O.                                                                                                         
\2\ Applicable only to long wet and dry kilns (i.e., not applicable to preheater and/or precalciner kilns).                                             
\3\ Emissions standard applicable only for cement kilns configured with a by-pass duct (typically preheater and/or precalciner kilns). Source must      
  comply with either the HC or CO standard in the by-pass stack.                                                                                        

    Information pertaining to the calculation of these floor emission 
levels can be found in U.S. EPA, ``Draft Technical Support Document for 
HWC MACT Standards, Volume III: Selection of Proposed MACT Standards 
and Technologies''.

B. Summary of MACT Floor Cost Impacts and Emissions Reductions.

    Under the 12 percent approach, the total national annualized 
compliance costs for existing sources to meet the MACT floor levels are 
estimated to be: (1) for incinerators, $28 million, with the cost per 
facility averaging $971,000; (2) for cement kilns, $59 million, with 
the cost per facility averaging $879,000; and (3) for LWAKs, $3 
million, with the cost per facility averaging $860,000. These total 
compliance costs equate to $49 per ton of hazardous waste burned for 
incinerators, $65 per ton of hazardous waste burned for cement kilns, 
and $52 per ton of hazardous waste burned for LWAKs. EPA estimates that 
up to four commercial incinerators will cease burning hazardous waste 
due to the compliance costs associated at the floor, in addition to 
three cement kilns and one lightweight aggregate kiln. However, we also 
believe that the these estimates are exaggerated because they are based 
on emissions levels determined during trial burns and compliance 
performance tests, which produce emissions far in excess of the 
emission levels most facilities achieve in day-to-day operation.
    There would be substantial emissions reductions at the MACT floor 
level, compared to baseline emissions. Table VIII.3 summarizes the 
estimated national emissions for incinerators if the facilities were 
operating at a level to meet the 12 percent MACT floor level. Also, the 
estimated percent reduction of HAP emissions from baseline are shown. 
Tables VIII.4 and VIII.5 show similar results for cement and 
lightweight aggregate kilns.

 Table VIII.3.--National Emissions Estimates for Incinerators 12 Percent
                              MACT Approach                             
------------------------------------------------------------------------
                                                              Percent   
                                                          reduction from
              HAP                  Annual emissions at       baseline   
                                     MACT floor level        emissions  
                                                             (percent)  
------------------------------------------------------------------------
Dioxin/Furans (TEQ)............  3.0 grams TEQ/yr.......              96
Mercury........................  0.2 tons/year..........              96
SVM (Cd, Pb)...................  1.0 tons/year..........              98
LVM (As, Cr, Sb, Be)...........  0.8 tons/year..........              97
HCl/Cl2........................  293 tons/year..........              83
Particulate Matter.............  650 tons/year..........              67
------------------------------------------------------------------------


 Table VIII.4.--National Emissions Estimates for Cement Kilns 12 Percent
                              MACT Approach                             
------------------------------------------------------------------------
                                                              Percent   
                                                          reduction from
              HAP                  Annual emissions at       baseline   
                                     MACT floor level        emissions  
                                                             (percent)  
------------------------------------------------------------------------
Dioxin/Furans (TEQ)............  7.0 grams TEQ/yr.......              99
Mercury........................  1.7 tons/year..........              71
SVM (Cd, Pb)...................  4.0 tons/year..........              87
LVM (As, Cr, Sb, Be)...........  0.9 tons/year..........              73
HCl/Cl2........................  761 tons/year..........              71
Particulate Matter.............  1877 tons/year.........              56
------------------------------------------------------------------------


Federal Register / Vol. 61, No. 77 / Friday, April 19, 1996 / 
Proposed Rules

[[Page 17414]]



                 Table VIII.5.--National Emissions Estimates for LWAKS 12 Percent MACT Approach                 
----------------------------------------------------------------------------------------------------------------
                                           Annual emissions at MACT floor     Percent reduction from baseline   
                   HAP                                 level                             emissions              
----------------------------------------------------------------------------------------------------------------
Dioxin/Furans (TEQ).....................  (not determined) 128...........  (not determined)                     
Mercury.................................  0.03 tons/year.................  91%.                                 
SVM (Cd, Pb)............................  0.04 tons/year.................  94%.                                 
LVM (As, Cr, Sb, Be)....................  0.07 tons/year.................  67%.                                 
HCl/Cl2.................................  2760 tons/year.................  9%.                                  
Particulate Matter......................  26 tons/year...................  45%.                                 
----------------------------------------------------------------------------------------------------------------

C. Alternative Floor Option: Percent Reduction Refinement

    The Agency is also considering whether to use a refinement 
technique in establishing the MACT floor that would modify either the 6 
percent approach, used as the basis of today's proposal, or the 12 
percent option discussed previously. This refinement attempts to 
address the unfavorable conditions (i.e. worst-case trial burn or COC 
testing) under which the emissions data was generated.
---------------------------------------------------------------------------

    \128\ The database is insufficient to make a realistic 
determination of the emissions at the baseline or for the 12 percent 
option.
---------------------------------------------------------------------------

    As discussed elsewhere, EPA is concerned that our hazardous waste 
emissions database is biased high due to the operating conditions that 
generated the data (e.g., metals and chlorine spiking, non-optimal APCD 
performance). Therefore, the analysis of this database results in floor 
levels that are artificially inflated and not adequately representative 
of day-to-day emissions levels. One simplified option to address this 
concern is to apply a ``percent reduction'' to the calculated floor 
levels derived from either the 6 percent or 12 percent approach. We 
invite comment on this approach particularly with respect to the 
appropriate percent reduction(s) to be applied. We also solicit 
information and data based on routine facility operations and emissions 
levels that could be used to calculate MACT floors that better reflect 
day-to-day operations and that would avoid the potential difficulties 
in attempting to determine the appropriate percent reduction(s) to be 
used.

IX. Additional Data for Comment

    The Agency has received submissions from various stakeholders 
detailing alternative approaches to establish MACT floor and beyond-
the-floor levels. The Agency has placed these submissions into the 
docket 129 for this rulemaking and specifically requests comment 
on the approaches used and the emission levels identified. This section 
provides some information on analyses conducted by the Cement Kiln 
Recycling Coalition and Waste Technologies Industries to determine MACT 
and MACT floor levels.
---------------------------------------------------------------------------

    \129\ In addition to the submission discussed in this section, 
the petitions in the docket for this rulemaking include: (1) 
Hazardous Waste Treatment Council (now Environmental Technology 
Council), ``Petition for Rulemaking under the Resource Conservation 
and Recovery Act to Establish Uniform National Performance Standards 
for all Combustion Facilities based on the Best Available 
Technology'', May 18, 1994; and (2) Cement Kiln Recycling Coalition, 
``Petition for Rulemaking under the Resource Conservation and 
Recovery Act to Modify the Rules for the Burning of Hazardous 
Waste'', January 18, 1994.
---------------------------------------------------------------------------

A. Data from Cement Kiln Recycling Coalition

    The Cement Kiln Recycling Coalition (CKRC) is a trade association 
with a membership comprised of cement companies that burn hazardous 
waste fuel and related companies engaged in the processing and 
marketing of these fuels. CKRC conducted a technical analysis of the 
hazardous waste-burning cement kiln's emissions database, identified 
the best performing sources and MACT control technology, and determined 
MACT floor emission levels for dioxin and furans and six metal HAPs. 
CKRC's initial analysis specified separate MACT floor levels based on 
cement kiln process type (i.e., separate floors were developed for 
cement kilns employing dry production processes and wet production 
processes).130 The MACT floor results are provided in Table IX.A.1 
below.
---------------------------------------------------------------------------

    \130\ Environmental Risk Sciences Incorporated (prepared for 
CKRC), ``An Analysis of Technical Issues Pertaining to the 
Determination of MACT Standards for the Waste Recycling Segment of 
the Cement Industry'' (Volumes I-III), May 3, 1995.

    Table IX.A.1.--CKRC's Proposed MACT Floor Emission Levels for Existing Cement Kilns (Based on Dry and Wet   
                                             Process Sub-categories)                                            
----------------------------------------------------------------------------------------------------------------
                 HAP                          Dry process CKs                       Wet Process CKs             
----------------------------------------------------------------------------------------------------------------
Arsenic..............................  3 g/dscm............  32 g/dscm.                       
Beryllium............................  0.3 g/dscm..........  24 g/dscm.                       
Cadmium..............................  30 g/dscm...........  62 g/dscm.                       
Chromium.............................  485 g/dscm..........  125 g/dscm.                      
Chromium (VI)........................  8 g/dscm............  29 g/dscm.                       
Lead.................................  143 g/dscm..........  911 g/dscm.                      
Mercury..............................  NA...........................  96 g/dscm.                       
Dioxins/Furans.......................  1.7 ng/dscm (TEQ)............  2.0 ng/dscm (TEQ).                        
----------------------------------------------------------------------------------------------------------------

    While CKRC states that sub-categorization is appropriate, they have 
analyzed recent data based on no sub-categorization and arrived at the 
floor levels and (generally) achievable beyond-the-floor (BTF) levels 
presented in Table IX.A.2.131 Note that this subsequent re-
analysis does not differentiate cement kilns by process type (i.e., wet 
and dry process). CKRC also emphasizes that the levels identified in 
Table IX.A.2 were derived assuming testing under normal facility 
operating conditions using hazardous waste as a fuel and does not 
reflect use

[[Page 17415]]

of continuous emissions monitors for PM or individual HAPs. In 
addition, CKRC emphasizes that, because of natural variations found in 
the cement industry (e.g., high levels of metals in some raw 
materials), not all kilns may be able to achieve these levels. CKRC 
believes this reinforces the need for the ability to make site-specific 
adjustments to the limits.
---------------------------------------------------------------------------

    \131\ Letter from Craig Campbell, CKRC, to James Berlow, U.S. 
EPA, undated but received February 20, 1996.

    Table IX.A.2.--CKRC's Alternate MACT Floor and Beyond-the-Floor Levels for Existing Cement Kilns (No Sub-   
                                                 categorization)                                                
----------------------------------------------------------------------------------------------------------------
                 HAP                          MACT floor level                        BTF levels                
----------------------------------------------------------------------------------------------------------------
Particulate matter...................  0.030 gr/dscf................  0.025 gr/dscf.                            
Mercury..............................  118 g/dscm..........  80 g/dscm.                       
Semivolatile metals..................  261 g/dscm..........  150 g/dscm.                      
Low-volatile metals..................  229 g/dscm..........  130 g/dscm.                      
----------------------------------------------------------------------------------------------------------------

    We invite comment on CKRC's approach to identify MACT floor and BTF 
levels.
    CKRC presented this re-analysis of MACT emissions levels in tandem 
with a recommendation that monitoring metals levels in collected cement 
kiln dust (CKD) is a more effective approach to ensure compliance with 
metals emission standards than monitoring the feedrate of metals in all 
feedstreams. CKRC suggested that CKD monitoring for metals should be 
used until CEM technologies become a workable alternative. Although CKD 
monitoring for metals is currently allowed under the BIF rule in lieu 
of feedstream monitoring and the same methodology is incorporated into 
today's proposal (see proposed Sec. 63.1210(n)(2)), CKRC has suggested 
revisions to the methodology to make it more workable. See Part Five, 
Section II.C.4.c.v of this preamble for a discussion of CKRC's 
recommendations.

B. Data from Waste Technologies Industries

    Waste Technologies Industries (WTI) has submitted data and 
information to the Agency pertaining to identification of MACT floor 
levels for incinerators.132 WTI raises the following issues: (1) 
in determining MACT floor, the Agency has not considered all of WTI's 
emissions data that have been submitted to the Agency; and (2) the 
Agency should subdivide the incinerator source category to develop 
separate MACT standards for commercial versus on-site incinerators.
---------------------------------------------------------------------------

    \132\ Letter from Barry Direnfeld, Swidler & Berlin, to Michael 
Shapiro, dated January 23, 1996, with an attached letter from Fred 
Sigg, Von Roll/WTI, to Sally Katzen, Office of Management and 
Budget, dated January 19, 1996.
---------------------------------------------------------------------------

    We have investigated WTI's concern about not considering its 
emissions data and, based on a preliminary analysis, determined that 
WTI's data would not affect the MACT floor levels that the Agency has 
identified for existing or new incinerators.133
---------------------------------------------------------------------------

    \133\ See memorandum from Bruce Springsteen, EER, to Shiva Garg, 
EPA, dated February 26, 1996, entitled ``Determination of the 
effects of the inclusion of new WTI test burn data on the MACT 
floors.''
---------------------------------------------------------------------------

    WTI is recommending that the Agency subdivide incinerators to 
develop separate standards for commercial and on-site sources. WTI 
notes that its emissions levels are substantially lower than the 
standards that (it believes) EPA is considering for proposal. In 
addition, WTI presents what it believes are appropriate MACT 
limitations for existing commercial, off-site incinerators.134 The 
table below compares WTI's suggested MACT limitations for commercial 
incinerators to the Agency's proposed standards:
---------------------------------------------------------------------------

    \134\ See letter from Gary Liberson, Environmental Risk 
Sciences, to Michael Shapiro, EPA, dated February 21, 1996.

----------------------------------------------------------------------------------------------------------------
              Pollutant                  WTI's recommended standard             EPA's proposed standard         
----------------------------------------------------------------------------------------------------------------
PM (mg/dscm).........................  33 (0.01 gr/dscf)............  69 (0.03 gr/dscf).                        
SVM (g/dscm)................  167..........................  270.                                      
LVM (g/dscm)                  72...........................  210.                                      
----------------------------------------------------------------------------------------------------------------

    We invite comment on whether incinerators should be subdivided by 
commercial, off-site units versus on-site units. Commenters should 
consider the criteria EPA uses to determine whether to subdivide a 
source category as discussed above in Section I of Part Four of this 
preamble. We also invite comment on WTI's approach to identify MACT 
limitations for commercial, off-site incinerators.

PART FIVE: IMPLEMENTATION

I. Selection of Compliance Dates

    Sections A and B below explain when existing and new facilities, 
respectively, would have to document compliance with the proposed MACT 
standards. Section C presents a proposal for a one year compliance 
extension in order to institute pollution prevention/waste minimization 
measures.
    EPA is proposing a different definition of compliance date for HWCs 
than is provided by existing 40 CFR Sec. 63.2. Although that section 
defines compliance date as the date when a source must be in compliance 
with the standards, 40 CFR Sec. 63.7 requires performance testing to 
document compliance with the emission standards (and performance 
evaluations to document compliance with requirements for continuous 
monitoring systems) after the compliance date. This use of the term 
``compliance date'' is not consistent with the current RCRA definition 
and regulatory requirements for HWCs.
    To achieve more consistency and to avoid potential duplication and 
conflict, the Agency is proposing to define compliance date for HWCs in 
Sec. 63.1201 as the date when a HWC must submit the initial 
notification of compliance. In addition, notification of compliance 
would be defined as a notification in which the owner and operator 
certify, after completion of performance evaluations and tests, that 
the HWC meets the emissions standards, CMS, and other requirements of 
Subpart EEE, Part 63, including establishing operating limits to meet 
standards for which compliance is not based on a CEM.

[[Page 17416]]

    For HWCs, initial compliance would thus mean that a facility has: 
(1) completed all modifications necessary to meet the standards; (2) 
conducted all emissions tests to verify compliance and set operating 
limits; (3) installed and satisfactorily performance tested all 
continuous monitoring systems (CMS) including continuous emissions 
monitors (CEMS); and (4) postmarked a letter to the director that 
transmits the (successful) emission results of the initial 
comprehensive performance test, performance test results for CMS, and 
all operating limits, and that states the facility is in compliance. 
Requirements to ensure compliance after the initial compliance 
notification are discussed in the preamble in Section II of Part Five.

A. Existing Sources

    EPA proposes that a facility be in compliance with these standards 
within three years after the date of publication of the final rule in 
the Federal Register (which is also the effective date of the rule). 
See proposed Sec. 63.1206(a). EPA believes that the vast majority of 
sources (approximately 90 to 95 percent) would require substantial 
modifications to operating and/or emission control equipment to comply 
with the proposed standards. Three years is a reasonable estimate of 
the time it will take for a facility to: read and analyze the final 
rule; conduct tests to identify cost-effective approaches to comply 
with the standards; complete the engineering analysis and design; 
fabricate, install, start up and shake down the modified facility; 
conduct preliminary emissions tests; conduct formal compliance testing; 
analyze samples and evaluate test results; prepare the notification of 
compliance; and obtain management certification of the results.
    Nonetheless, the Agency believes that some sources would be able to 
comply with the rule (i.e., submit a notification of compliance) before 
three years after the date of publication of the final rule. For 
example, some sources may require only minor modifications to emission 
control equipment and could comply substantially sooner than sources 
that need a major retrofit. Accordingly, we invite comment on how such 
sources could be identified and strategies that could be used to 
encourage or require them to comply at the earliest possible date.
    We note that the CAAA allows a maximum compliance period of three 
years (see Sec. 112(I)(3)(A)), unless a waiver is granted on a case-
specific basis. Section 63.6(i)(4)(i)(A) provides for a one year time 
extension ``if such additional time period is necessary for the 
installation of controls.'' If an owner or operator needs to modify the 
RCRA permit in order to allow modifications to the facility necessary 
to comply with the MACT standards, we believe inability to comply with 
the MACT standards within three years because of the need to modify the 
RCRA permit could constitute a valid reason for granting a time 
extension under Sec. 63.6(i). See discussion below. That is, the 
modification to the RCRA permit would be needed ``for the installation 
of controls.''
    Sources with RCRA permits can modify their facilities only after 
complying with the permit modification procedures of 40 CFR 270.42. If 
an owner and operator make a good faith effort to obtain the permit 
modification in time to submit a notification of compliance under 
today's proposed rule within three years of the effective date but 
cannot do so for reasons beyond their control (for example, the state 
in which the facility is located is in the process of receiving 
oversight authority, or the Agency is unable to respond in a timely 
manner to all permit modification requests), the Administrator may 
grant a one-year time extension.
    Note also that, as discussed above, the one-year time extension 
provided by Sec. 63.6(i) applies to a different definition of 
compliance than that proposed by today's rule for HWCs. By the date of 
compliance under this proposal, a HWC must have submitted a 
notification of compliance as defined above. Thus, although we are 
proposing a one-year time extension for initial compliance for HWCs 
using the procedures established in existing Sec. 63.6(i), a HWC must 
submit a notification of compliance by the end of the time extension, 
if granted, while other MACT sources would continue under the current 
rules unamended (i.e., they would conduct their performance test after 
the end of the time extension). See existing Sec. 63.7(a).
    A special case for HWCs exists for an existing unit that would not 
be subject to regulation on the effective date of this rule because it 
does not burn a hazardous waste but which subsequently becomes subject 
to regulation under today's proposed MACT standards because one of its 
waste streams later becomes a newly identified or listed hazardous 
waste. In this case, we propose that the facility be considered an 
``existing source'', since it would be inappropriate to apply new 
source MACT to a facility which has not altered its conduct, and which 
only becomes subject to this rule because of additional regulatory 
action taken by EPA (or an authorized state). Such a facility would 
have three years after the date of publication in the Federal Register 
of the final rule listing the waste as hazardous to come into 
compliance with these regulations.135
---------------------------------------------------------------------------

    \135\ Note that in other cases, an existing source that begins 
to burn hazardous waste after the effective date of this rule (and 
therefore changes its conduct) is classified as a new source and 
would have to comply with today's rules when the hazardous waste is 
first burned. The source would also have to obtain a RCRA operating 
permit before commencing hazardous waste management activities since 
it would be ineligible for interim status (assuming it is conducting 
no other hazardous waste management activities).
---------------------------------------------------------------------------

    Finally, EPA wants to ensure that only those facilities that plan 
to comply with the new regulations are allowed to burn hazardous waste 
during the compliance period. Accordingly, the rule would provide that, 
if the owner or operator of an existing source did not submit a 
notification of compliance by the applicable date, the source must 
immediately stop burning hazardous waste when the owner or operator 
first determines that the notification will not be submitted by the 
applicable date (i.e., following the effective date, but well before 
the compliance deadline) and could not resume burning hazardous waste 
except under the requirements for new MACT sources. To comply with the 
deadline for the initial notification of compliance, a source will have 
had to begin making preparations well in advance of the deadline. We 
invite comment on strategies that could be used to determine when a 
source could realistically determine whether or not it will meet the 
notification deadline and comply with the new standards.
    We note that there would also be substantial RCRA implications for 
a facility that does not comply with the applicable deadlines in a 
timely fashion. In particular, the source could not resume burning 
hazardous waste without being issued a RCRA operating permit. Further, 
if the source had already been issued a RCRA operating permit, 
hazardous waste could only be burned (after missing the deadline for 
submitting an initial notification of compliance) for a total of 720 
hours and only for the purpose of pretesting or comprehensive 
performance testing. Finally, if a source with a RCRA operating permit 
failed to submit an initial notification of compliance by the deadline, 
the source must, within 90 days of missing the initial notification of 
compliance, either submit a notification of compliance with MACT new 
standards or begin RCRA closure procedures unless the Administrator 
grants an extension of time in writing prior to the 90-day deadline for 
good cause. Examples of good cause that the Agency would be willing to 
evaluate

[[Page 17417]]

are: the facility now must undergo significant modifications in order 
to comply with the more stringent MACT new standards that will take 
longer to complete than the deadline allows, or the facility must 
contract for substantial new services in order to show compliance with 
the new standards.
    EPA believes that these requirements are necessary to ensure that 
owners and operators that elect not to comply with the standards do not 
continue to burn hazardous waste beyond the date on which the source 
determines that they will not comply with the promulgated standards.

B. New Sources

    Section 63.6 states that new or reconstructed sources ``shall 
comply with such standard[s] upon startup of the source.'' See also 
proposed Sec. 63.1206(b). One exception, available only to facilities 
which commence construction between proposal and promulgation, is in 
the instance where a standard more stringent than the one proposed is 
promulgated. In this instance, three years can be granted for the new 
source to be in compliance with the standard which is more stringent. 
The new source shall be in compliance upon startup with all standards 
which are not more stringent than those proposed. Section 63.2 defines 
new source as ``* * * any affected source the construction or 
reconstruction of which is commenced after the Administrator first 
proposes a relevant emission standard * * * .'' For discussion on 
reconstruction, see section VII.C. of this part of this preamble.

C. One Year Extensions for Pollution Prevention/Waste Minimization

    EPA is also seeking comment on a proposal to consider extension of 
compliance deadlines for up to one year beyond the three year deadline 
from the date of promulgation of this rule, on a case-by-case basis, 
for facilities which request an extension to implement pollution 
prevention/waste minimization measures that will enable the facility to 
meet MACT standards and that cannot practically be implemented within 
the three year compliance deadline.
    During development of the Hazardous Waste Minimization National 
Plan (released in 1994), some companies pointed out that short 
compliance deadlines after the promulgation of some rules have 
precluded them from completing necessary pollution prevention planning 
and implementation that would facilitate meeting compliance 
requirements through source reduction and environmentally sound 
recycling. As a result, companies opt for installing often expensive 
``end-of-pipe'' pollution controls in order to meet compliance 
deadlines. In addition, once capital has been sunk into end-of-pipe 
pollution controls which are large enough to handle current and future 
waste volumes, there is little incentive for companies to then spend 
money exploring pollution prevention/waste minimization options.
    EPA believes that the three year compliance deadline for meeting 
the MACT standards in this rulemaking should in most cases be 
sufficient for a facility to complete the pollution prevention planning 
and implementation that might be necessary to meet MACT standards. In 
cases where facilities can provide information that shows that 
additional time is necessary to complete this process, EPA is proposing 
to grant up to a one year extension for facilities to complete 
pollution prevention planning and implementation, and to satisfy all of 
the procedures in this rule for demonstrating compliance. This proposed 
extension is consistent with other portions of today's proposal, 
including the section on permitting procedures which describes 
pollution prevention/waste minimization options during the permitting 
process.

II. Selection of Proposed Monitoring Requirements

    Section 114(a) of the CAA requires monitoring to ensure compliance 
with the standards and the submission of periodic compliance 
certifications for all major stationary sources. Given that all HWCs 
are subject to regulation as major sources, the proposed compliance 
monitoring requirements discussed below would apply to all HWCs.
    In this section we discuss the following: (a) the compliance 
monitoring hierarchy; (b) how operations during comprehensive 
performance testing would be used to establish limits for operating 
parameters; (c) for each emission standard, requirements for continuous 
emissions monitors (if any) and limits on operating parameters to 
ensure compliance; (d) compliance with controls on fugitive combustion 
emissions; (e) requirements for automatic waste feed cutoffs and 
emergency safety vent openings; (f) quality assurance requirements for 
continuous monitoring systems (CMS); and (g) protocols to ensure and 
document compliance.

A. Monitoring Hierarchy

    The proposed compliance monitoring requirements were developed by 
examining the hierarchy of monitoring options available for specific 
processes, pollutants, and control equipment. The approach involves 
describing, on an emission standard specific basis, what monitoring is 
required for a source to be in compliance. This approach was also used 
for the secondary lead smelter MACT (59 FR at 29772, June 9, 1994), 
another rule where the sources process hazardous waste.
    The monitoring hierarchy is three-tiered. The top tier of the 
monitoring hierarchy is the use of a continuous emissions monitor 
system (CEMS, also known as ``CEM'') for that HAP or standard. In the 
absence of a CEMS for that HAP or standard, the second tier is the use 
of a CEMS for a surrogate of that HAP or standard and, when necessary, 
setting some operating limits to account for the limitations of using 
surrogates. Lacking a CEMS for either, EPA sets appropriate feedstream 
and operating parameter limits to ensure compliance and requires 
periodic testing of the source. In developing this proposal each tier 
of the hierarchy was evaluated relative to its technical feasibility, 
cost, ease of implementation, and relevance to its underlying process 
emission limit or control device.
    The proposed standards for hazardous waste combustors contain 
monitoring requirements for process stack emissions and combustion 
fugitive emissions. The proposed standards require either pollutant 
monitoring directly through the use of a CEMS, surrogate monitoring 
through the use of a CEMS, and/or parameter monitoring that indicates 
proper operation and maintenance of a control device. Recordkeeping is 
also required to ensure that specific work practices are being 
followed. Section VI of this part discusses recordkeeping.

B. Use of Comprehensive Performance Test Data to Establish Operating 
Limits

    Limits on operating parameters (e.g., feedrate limits, temperature 
limits) would be based on levels that are achieved during the 
comprehensive performance test. See section III of this part for the 
discussion on comprehensive performance tests.
1. Averaging Periods for Limits on Operating Parameters
    The Agency is proposing various averaging periods for the limits on 
operating parameters: a ten-minute rolling average; a one-hour rolling 
average; and a 12-hour rolling

[[Page 17418]]

average.136 To show compliance with any of these rolling averages 
with respect to operating parameters that are established based on 
levels achieved during the comprehensive performance test (rather than 
on manufacturer specifications), the monitor must make a measurement of 
the parameter at least once each 15 seconds, and four 15-second 
measurements must be averaged each minute to determine a one-minute 
average. Then, each one-minute average is considered along with the 
previous one-minute averages over the averaging period to calculate a 
new rolling average level each minute. Thus, irrespective of the 
averaging period, a new rolling average level is calculated each 
minute.
---------------------------------------------------------------------------

    \136\  We note that today's rule would establish an 
instantaneous limit, i.e., a limit where no averaging is allowed, to 
ensure that less than ambient pressure is maintained in the 
combustion system at all times to control fugitive combustion 
emissions.
---------------------------------------------------------------------------

    The duration of the averaging period affects the number of one-
minute averages used to calculate the level. For example, if a limit is 
based on a 12-hour rolling average, each new one-minute average is 
added to the previous 719 one-minute average values to calculate a new 
12-hour rolling average value each minute.
    A ten-minute average is proposed when the Agency is concerned that 
short-term perturbations above the limit will result in high emissions 
that cannot be offset by lower emissions during periods of more 
appropriate operation.137 Since the ten-minute average is used to 
control short-term perturbations and does not control average 
emissions, it will always be used with a one hour average designed to 
control average emissions. (An exception is when the 10-minute average 
is used to control a design specification of the APCD manufacturer. In 
this event, a ten-minute average may be used alone.) It could be argued 
that a short term averaging period other than ten minutes could be 
used. However, the Agency is concerned about setting the averaging 
period shorter than 10 minutes. Shorter averaging periods would result 
in more extreme (i.e., absolute maximum or minimum) limits and could 
lead to higher emissions. Conversely, EPA could set a short-term 
averaging period longer than ten minutes, but believes that ten minutes 
is an appropriate, achievable, conservative, and reasonable duration 
for the short averaging period.
---------------------------------------------------------------------------

    \137\ An example is for inlet temperature to dry PM APCDs to 
control dioxin. Dioxin increases exponentially with increasing 
temperature, so a short-term increase in temperature will not be 
offset by short-term decreases in dioxin emissions.
---------------------------------------------------------------------------

    A one-hour averaging period is proposed in instances where the 
Agency is less concerned about perturbations and/or wants to limit 
average emissions.138 Hourly rolling averages are currently 
required under the BIF rule and are required for some incinerators. The 
value of one-hour averages will tend to be less extreme than 10-minute 
averages since perturbations are averaged out over more normal data 
and, thus, are better at controlling average emissions than 10-minute 
averages. It could be argued that an averaging period shorter than one 
hour would be appropriate, but EPA is selecting a ten-minute average to 
control perturbations and believes this is sufficient. It could be 
argued that averaging periods longer than one hour could also be 
appropriate, but setting limits on operating parameters is at the 
bottom of the monitoring hierarchy and, as such, a conservative 
approach is preferable.
---------------------------------------------------------------------------

    \138\ An example is flue gas flowrate. This parameter is 
important, but slight increases in flow rate can be offset by 
proportionate decreases in flowrate. Therefore, average flowrate is 
important without regard to perturbations.
---------------------------------------------------------------------------

    The twelve-hour averages are being proposed in instances when the 
Agency wants to control average emissions and is concerned that the 
one-hour average may not be achievable or may be overly restrictive. 
Twelve-hour averages are proposed only for feedrates: metals and 
chlorine. For each of these, feedstream analysis is necessary to 
determine the concentration in each of the feedstreams and this makes 
using an averaging period shorter than twelve hours problematic. EPA 
could use an averaging period longer than twelve hours, but believes 
that twelve hours is achievable. EPA is concerned about this 12-hour 
average in that it may be inconsistent with averaging periods for CEMS; 
namely, it is longer than the metals, HCl, Cl2, or PM averaging 
periods. A 12-hour average is inconsistent because, at the top of the 
monitoring hierarchy, CEMS averaging periods should be longer, i.e., 
less conservative, than feedstream monitoring, at the bottom of the 
hierarchy. EPA invites comment on this issue. Alternate averaging 
periods for chlorine and metals feedrates are discussed below in the 
appropriate sections.
    As noted earlier, for compliance with these averaging periods, EPA 
proposes that averages be calculated every minute on a rolling-average 
basis. It is also proposed that the one-minute average be the average 
of the previous four measurements taken at 15-second intervals. This is 
the approach required by the BIF rule. All 15-second measurements would 
be used without smoothing, rounding, or data checks. No 15-second 
observations may be ``thrown out'' for any reason.
2. How Limits Would Be Established from Comprehensive Test Data
    This section explains how operating limits for the averaging 
periods discussed above are established from the comprehensive test 
data. Note that all averages are rolling averages, based on a one-
minute average.
    Ten-minute rolling averages would be established as the average 
over all comprehensive test runs of the highest or lowest (as 
specified) ten-minute rolling average for each run.
    One of two approaches would be specified to establish limits on an 
hourly rolling average basis: an average level or an average of the 
highest or lowest (as specified) hourly rolling average. In most cases, 
it is derived by averaging all of the one-minute averages during all 
the runs of the comprehensive performance test. In the few cases when 
an average of the maximum hourly rolling averages is specified, the 
limit is derived by taking the average of the highest hourly average 
for each run of the comprehensive performance test.
    Twelve-hour rolling averages for feedstreams would be derived by 
averaging all of the one-minute averages during all the runs of the 
comprehensive performance test irrespective of the total duration of 
the test.139 Separate twelve-hour averages would apply to all feed 
locations.
---------------------------------------------------------------------------

    \139\ Or, if the source elects to define different operating 
modes and conduct performance testing under each mode, the one-
minute averages would be averaged for all runs for each test 
condition (representing each mode of operation).
---------------------------------------------------------------------------

3. Example of How Limits Would Be Established
    For example, if a facility were to have a fabric filter (FF), it 
might have a limit on maximum FF inlet temperature on a ten-minute 
average to ensure compliance with the dioxin and furan standard. If 
this is the case, during the comprehensive performance test, the 
facility would monitor FF inlet temperature. The facility would then 
take the highest single ten-minute rolling averages of FF inlet 
temperature from each of the three comprehensive test runs and average 
them together. If these single largest ten minute rolling averages from 
each of the three runs were 140, 150, and 160 deg.C, then the maximum 
ten-minute rolling average for FF inlet temperature would be 150 deg.C.
    If the same parameter were also to have an hourly rolling average 
based on all data from all runs, the facility would

[[Page 17419]]

sum up all one-minute averages occurring during the comprehensive 
performance test and average them together. This would become the 
hourly rolling average for this parameter.
    Twelve-hour feedrate limits are calculated similarly. For SVM, the 
facility would sum the total feed from all runs of the comprehensive 
performance test and divide that sum by the number of minutes of all 
three runs of the comprehensive test. For this example, assume that 
both Cd and Pb are fed during the comprehensive performance test, that 
the feedrate for Cd was 5, 30, and 25 and for Pb was 100, 70, and 85 
for each of the three runs of the comprehensive performance test and 
that the time duration of each run was 205, 230, and 195 minutes. The 
total amount of SVM fed would be 315 and the time duration of the test 
would be 630 minutes. Therefore, the SVM limit would be 315, divided by 
630 minutes, or 0.50. During normal operation the SVM feedrate would be 
calculated every minute to ensure it does not exceed the 0.50 SVM limit 
by averaging the current and previous 719 one-minute averages.

C. Compliance Monitoring Requirements

    Monitoring requirements are proposed to ensure compliance with the 
following emission standards: dioxin and furan (D/F), mercury (Hg), 
semivolatile metals (SVM), low-volatile metals (LVM), carbon monoxide 
(CO), hydrocarbons (HC), hydrochloric acid (HCl) and chlorine gas (Cl2) 
(combined and reported as HCl), and particulate matter (PM). See 
proposed Sec. 63.1210. Monitoring requirements for combustion fugitive 
emissions are proposed as well.
    Table V.2.1 summarizes today's proposed compliance monitoring 
requirements.
1. Continued Applicability of RCRA Omnibus Authority
    When a RCRA operating permit is issued under Part 270 after a 
source has submitted its initial notification of compliance with the 
proposed MACT standards, a permit writer would continue to have the 
discretion currently provided by Sec. 264.345(b)(6) of the incinerator 
standards and Secs. 266.102(e) subparagraphs (2)(i)(G), (3)(i)(E), 
(4)(ii)(J), (4)(iii)(J), and (5)(i)(G) of the BIF standards to 
supplement these operating parameter limits as necessary to protect 
human health and the environment on a site-specific basis to ensure 
that today's proposed emission standards are being met. This means the 
RCRA permit writer's authority to use instantaneous limits or averaging 
periods other than those specified here, or require operating 
parameters in addition to those specified here, is maintained during 
the RCRA permitting process. See proposed Secs. 264.340(b)(2)(iii) and 
266.102(a)(2)(ii).

                                                                 Table V.2.1.--Summary Table of Proposed Monitoring Requirements                                                                
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                        HCl &                                                                   
              Device                      Parameter          D/F       Hg        PM        SVM       LVM     CO & HC     Cl2         Limits from           Avg period           Limits set as   
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Continuous Monitor................  Stack CEMS..........  ........             (1)       (1)          (1)  CEMS Stnds..........  varies..............  Units of Standard.  
                                    Max Inlet Temp to             (2)  ........        ........  ........  Comp Test...........  10 min..............  Avg of Max 10 min   
                                     Dry PM APCD.                                                                                                     1 hour..............   RA.                
                                                                                                                                                                            Avg over all runs.  
Carbon Injection..................  Min Carbon Injection          (2)  ........  ........  ........  ........  ........  Comp Test...........  10 min..............  Avg of Min 10 min   
                                     Feedrate (Carbon                                                                                                 1 hour..............   RA.                
                                     Feed through                                                                                                                           Avg over all runs.  
                                     Injector).                                                                                                                                                 
                                    Min Carrier Fluid             (2)  ........  ........  ........  ........  ........  Manuf Spec..........  10 min..............  ....................
                                     Flowrate or Nozzle                                                                                                                                         
                                     Pressure Drop.                                                                                                                                             
                                    Carbon Specs........          (2)  ........  ........  ........  ........  ........  Comp Test...........  n/a.................  Same brand and type.
Carbon Bed........................  Max Age of Carbon             (2)  ........  ........  ........  ........  ........  Initial Comp Test...  n/a.................  Manuf specs (no C   
                                     (Time in-use).                                                                                                                          aging).            
                                                          ........                                                              Conf Tests..........  n/a.................  Normal C Change-out 
                                                                                                                                                                             Schedule.          
                                                          ........                                                              Sub. Comp. Tests....  n/a.................  Max C Age is the age
                                                                                                                                                                             during subsequent  
                                                                                                                                                                             Comp Tests.        
                                    Carbon Specs........          (2)  ........  ........  ........  ........  ........  Comp Test...........  n/a.................  Same brand and type.
Dioxin Inhibitor..................  Min Inhibitor            ........  ........  ........  ........  ........  ........  Comp Test...........  10 min..............  Avg of Min 10 min   
                                     Feedrate.                                                                                                        1 hour..............   RA.                
                                                                                                                                                                            Avg over all runs.  
                                    Inhibitor                ........  ........  ........  ........  ........  ........  Comp Test...........  n/a.................  Same brand and type.
                                     Specifications.                                                                                                                                            

[[Page 17420]]

                                                                                                                                                                                                
Catalytic Oxidizer................  Min Fine Gas Temp at     ........  ........  ........  ........  ........  ........  Comp Test...........  10 min..............  Avg of Min 10 min   
                                     Entrance.                                                                                                        1 hour..............   RA.                
                                                                                                                                                                            Avg over all runs.  
                                    Max Age (Time in-        ........  ........  ........  ........  ........  ........  Manuf Spec..........  As specified........                      
                                     use).                                                                                                                                                      
                                    Catalyst Replacement     ........  ........  ........  ........  ........  ........  Comp Test...........  n/a.................  Same as used during 
                                     Specs:.                                                                                                                                 previous Comp Test.
                                    --Catalytic Metal                                                                                                                                           
                                     Loading (each                                                                                                                                              
                                     metal).                                                                                                                                                    
                                    --Space Time........                                                                                                                                        
                                    --Substrate                                                                                                                                                 
                                     Construction                                                                                                                                               
                                     (mat'ls, pore size).                                                                                                                                       
                                    Max Flue Gas Temp at     ........  ........  ........  ........  ........  ........  Manuf Spec..........  10 min..............  As specified.       
                                     Entrance.                                                                                                                                                  
Good Combustion...................  Maximun Batch Size,      ........  ........  ........  ........  ........  ........  Comp Test...........  n/a.................  Lightest batch fed. 
                                     Feeding Frequency,                                                                                                                      Least frequent     
                                     and Minimum Oxygen                                                                                                                      feeding Highest O2 
                                     Concentration.                                                                                                                          level.             
                                    Max Waste Feedrate..     ........  ........  ........  ........  ........  ........  Comp Test...........  1 hour..............  Avg of Max 1 hour   
                                                                                                                                                                             RA.                
                                    Min Comb Chamber         ........  ........  ........  ........  ........  ........  Comp Test...........  10 min..............  Avg of Min 10 min.  
                                     Temp (Exit of Each                                                                                               1 hour..............   RA                 
                                     Chamber).                                                                                                                              Avg over all runs.  
Good Combustion and APCD            Max Flue Gas                  (2)       (2)       (2)       (2)  ........     Comp Test...........  1 hour..............  Avg of Max 1 hour   
 Efficiency.                         Flowrate or                                                                                                                             RA.                
                                     Production Rage.                                                                                                                                           
Feed Control......................  Max Total Metals      ........       (2)  ........        ........  ........  Comp Test...........  12 hour.............  Avg over all runs.  
                                     Feedrate (all                                                                                                                                              
                                     streams).                                                                                                                                                  
                                    Max Pumpable Liquid   ........  ........  ........  ........     ........  ........                                                                  
                                     Metals Feedrate.                                                                                                                                           
                                    Max Total Ash         ........  ........       (2)  ........  ........  ........  ........  Comp Test...........  12 hour.............  Avg over all runs.  
                                     Feedrate (all                                                                                                                                              
                                     streams).                                                                                                                                                  
                                    Max Total Chlorine    ........  ........  ........        ........     Comp Test...........  12 hour.............  Avg over all runs.  
                                     Feedrate (all                                                                                                                                              
                                     streams).                                                                                                                                                  
Wet Scrubber......................  Min Press Drop             (2)       (2)       (2)       (2)       (2)  ........     Comp Test...........  10 min..............  Avg of Min 10 min RA
                                     Across Scrubber.                                                                                                 1 hour..............  Avg over all runs.  
                                    Min Liquid Feed            (2)       (2)       (2)       (2)       (2)  ........     Manuf Spec..........  10 min..............  n/a                 
                                     Press.                                                                                                                                                     
                                    Min Liquid pH.......  ........       (2)  ........  ........  ........  ........     Comp Test...........  10 min..............  Avg of Min 10 min RA
                                                                                                                                                      1 hour..............  Avg over all runs.  
                                    Min Blowdown (Liq          (2)       (2)       (2)       (2)       (2)  ........  ........  Comp Test...........  10 min..............  Avg of Min/Max 10   
                                     Flowrate) or Max                                                                                                 1 hour..............   min RA             
                                     Solid Content in                                                                                                                       Avg over all runs.  
                                     Liq.                                                                                                                                                       

[[Page 17421]]

                                                                                                                                                                                                
                                    Min Liq Flow to Gas        (2)       (2)       (2)       (2)       (2)  ........     Comp Test...........  10 min..............  Avg of Min 10 min RA
                                     Flow Ratio.                                                                                                      1 hour..............  Avg over all runs.  
Ionizing Wet Scrubber.............  Min Press Drop             (2)       (2)       (2)       (2)       (2)  ........     Comp Test...........  10 min..............  Avg of Min 10 min RA
                                     Across Scrubber.                                                                                                 1 hour..............  Avg over all runs.  
                                    Min Liquid Feed            (2)       (2)       (2)       (2)       (2)  ........     Manuf Spec..........  10 min..............  n/a                 
                                     Pressure.                                                                                                                                                  
                                    Min Blowdown (Liq          (2)       (2)       (2)       (2)       (2)  ........  ........  Comp Test...........  10 min..............  Avg of Min/Max 10   
                                     Flowrate) or Max                                                                                                 1 hour..............   min RA             
                                     Solid Content in                                                                                                                       Avg over all runs.  
                                     Liq.                                                                                                                                                       
                                    Min Liq Flow to Gas        (2)       (2)       (2)       (2)       (2)  ........     Comp Test...........  10 min..............  Avg of Min 10 min RA
                                     Flow Ratio.                                                                                                      1 hour..............  Avg over all runs.  
                                    Min Power Input            (2)       (2)       (2)       (2)       (2)  ........  ........  Comp Test...........  10 min..............  Avg of Min 10 min RA
                                     (kVA: current and                                                                                                1 hour..............  Avg over all runs.  
                                     voltage).                                                                                                                                                  
Dry Scrubber......................  Min Sorbent Feedrate  ........  ........  ........  ........  ........  ........     Comp Test...........  10 min..............  Avg of Min 10 min   
                                                                                                                                                      1 hour..............   RA.                
                                                                                                                                                                            Avg over all runs.  
                                    Min Carrier Fluid     ........  ........  ........  ........  ........  ........     Manuf Spec..........  10 min..............  n/a                 
                                     Flowrate or Nozzle                                                                                                                                         
                                     Pressure Drop.                                                                                                                                             
                                    Sorbent               ........  ........  ........  ........  ........  ........     Comp Test...........  n/a.................  Same brand and type.
                                     Specifications.                                                                                                                                            
FF................................  Min Press Drop             (2)       (2)       (2)       (2)       (2)  ........  ........  Comp Test...........  10 min..............  Avg of Min 10 min   
                                     Across Device.                                                                                                   1 hour..............   RA.                
                                                                                                                                                                            Avg over all runs.  
ESPs..............................  Min Power Input            (2)       (2)       (2)       (2)       (2)  ........  ........  Comp Test...........  10 min..............  Avg of Min 10 min   
                                     (kVA: current and                                                                                                1 hour..............   RA.                
                                     voltage).                                                                                                                              Avg over all runs.  
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:                                                                                                                                                                                          
1=Stack CEMS is optional for the SVM, LVM, and HCl and Cl2 standards. If a CEMS is used for compliance, none of the feedstream and operating parameters for that HAP would apply.               
(2)=If CEMS are not required in the final rule for PM and/or Hg, the operating limits for these parameters would apply.                                                                         
Definitions:                                                                                                                                                                                    
``Comp Test''=Comprehensive Performance Test.                                                                                                                                                   
``Conf Test''=Confirmatory Performance Test.                                                                                                                                                    


2. Dioxin and Furan (D/F)
    EPA is proposing that sources comply with the D/F standard by 
establishing and complying with limits on operating parameters and 
performing D/F test every 18 months (or 30 months for small on-site 
facilities). Table V.2.2 summarizes these limits. See also proposed 
Sec. 63.1210(j).

                   Table V.2.2.--Summary of Proposed Dioxin and Furan Monitoring Requirements                   
----------------------------------------------------------------------------------------------------------------
                                                                                                 How limit is   
                                                                                               established from 
                                   Compliance using       Limits from         Avg. period      comp performance 
                                                                                                     test       
----------------------------------------------------------------------------------------------------------------
Particulate Matter (PM) Control.  PM CEMS...........  Comp Test.........  10 min............  Avg of Max 10-min 
                                                                                               RAs.             
                                                                          1 hour............  Avg over all runs.
Good Combustion.................  CO and HC CEMS....  MACT Std..........  1 hour............  N/A.              
                                  Min comb chamber    Comp Test.........  10 min............  Avg of Max 10-min 
                                   tempt: CMS at                                               RAs.             
                                   exit of each                                                                 
                                   chamber.                                                                     
                                                                          11 hour...........  Avg over all runs.
                                  Max waste feedrate  Comp Test.........  1 hour............  Avg of Max 1 hour 
                                   CMS.                                                        RAs.             

[[Page 17422]]

                                                                                                                
                                  For batch fed       Comp Test.........  None..............  N/A.              
                                   sources: limit on                                                            
                                   batch size,                                                                  
                                   feeding                                                                      
                                   frequency, and                                                               
                                   minimum oxygen.                                                              
Max Inlet Temp to Dry PM APCD...  Temp CMS..........  Comp Test.........  10 min............  Avg of Max 10 min 
                                                                                               RAs.             
                                                                          1 hour............  Avg over all runs.
Max Flue Gas Flowrate or          Flowrate CMS or     Comp Test.........  1 hour............  Avg of Max 1 hour 
 Production Rate.                  Production Rate.                                            RAs.             
Min Carbon Injection Feed.......  Feedrate CMS......  Comp Test.........  10 min............  Avg of Min 10 min 
                                                                                               RAs.             
                                                                          1 hour............  Avg over all runs.
Min Carrier Fluid Flowrate or     same..............  Manuf Spec........  10 min............  N/A.              
 Nozzle Pressure Drop.                                                                                          
Carbon Specs....................  Brand and Type....  Comp Test.........  N/A...............  Same brand and    
                                                                                               type.            
Max Carbon Age, Carbon Bed......  Max Carbon          Initial Comp Test.  N/A...............  Manuf Specs (no C 
                                   Lifetime.                                                   aging).          
                                                      Conf Tests........  N/A...............  Normal C Change-  
                                                                                               out Schedule.    
                                                      Sub. Comp Tests...  N/A...............  Max C Age is the  
                                                                                               age during sub.  
                                                                                               Comp Tests.      
Min Flue Gas Temp, Catalytic      Inlet to Catalyst.  Comp Test.........  10 min............  Avg of Min 10 min 
 Oxidizer.                                                                                     RAs.             
                                                                          1 hour............  Avg over all runs.
Max Age, Catalytic Oxidizer.....  Time in use.......  Manuf Spec........  As specified......                    
Catalyst Replacement Specs......  Catalytic Metal     Comp Test.........  N/A...............  Same as used      
                                   Loading.                                                    during comp test.
                                  Space Time........                                                            
                                  Substrate                                                                     
                                   Construct:                                                                   
                                   mat'ls, pore size.                                                           
Max Flue Gas Temperature,         Inlet to Catalyst.  Manuf Spec........  10 min............  As specified.     
 Catalytic Oxidizer.                                                                                            
Min Inhibitor Feedrate..........  Feedrate CMS......  Comp Test.........  10 min............  Avg of Min 10 min 
                                                                                               RAs.             
                                                                          1 hour............  Avg over all runs.
Inhibitor Specs.................  None..............  Comp Test.........  N/A...............  Same brand and    
                                                                                               type.            
----------------------------------------------------------------------------------------------------------------



    a. Evaluation of Monitoring Options. D/F partitions into two phases 
in stack emissions: a portion is adsorbed onto particulate and a 
portion is emitted as a vapor (gas). Given that there is no CEMS for D/
F, the Agency is proposing to require a combination of approaches to 
control D/F emissions: (1) compliance with a site-specific PM limit to 
control adsorbed D/F; (2) operation under good combustion conditions to 
minimize D/F precursors; (3) temperature control at the PM control 
device to limit D/F formation in the control device; and (4) compliance 
with operating limits on
D/F control equipment (e.g., carbon injection) that a source may elect 
to use.
    b. Operating Parameter Limits. Today's proposed rule would limit 
the following operating parameters to satisfy the combination of 
approaches discussed in the previous paragraph.
    i. Control of PM Emissions: To control D/F and other PICs that are 
adsorbed to PM, the rule would require that sources limit PM emissions 
to the site-specific level that occurs when demonstrating compliance 
with the D/F (and SVM and LVM) emission standards. The site specific 
operating limit for PM would be capped at (i.e., could not exceed) the 
proposed national MACT standard of 69 mg/dscm. See section 7 of this 
section for a discussion on the control of PM emissions.
    ii. Good Combustion: CO and HC Limits. EPA is proposing CO and HC 
standards to ensure good combustion to help minimize D/F precursors. 
See discussion below (section 5 of this section) for the explanation of 
the CO and HC emission standards.
    iii. Good Combustion: Maximum Waste Feedrate. An increase in waste 
feedrate without a corresponding increase in combustion air can cause 
inefficient combustion that may produce (or incompletely destroy) D/F 
precursors. Therefore EPA proposes to limit waste feedrate. For 
incinerators, waste feedrate limits would be established for each 
combustion chamber to minimize combustion perturbations. For CKs and 
LWAKs waste feedrate limits would be established for each location 
where waste is fed (e.g., the hot end where product is discharged, mid-
kiln, and at the cold end where raw material is fed.140
---------------------------------------------------------------------------

    \140\ Waste feedrate limits would also be established for waste 
fed into a preheater or precalciner system of a cement kiln 
facility.
---------------------------------------------------------------------------

    Feedrate limits would be established on an hourly rolling average 
basis as the average of the highest hourly rolling average for each 
run. We specifically invite comment on whether it would be more 
appropriate to establish the limit based on the average hourly rolling 
average over all runs. EPA is not proposing this more stringent 
approach because we consider waste feedrate to be a secondary control 
parameter that may not require such strict control.
    See also the discussion in section II.F.2 below for other 
requirements to document compliance with feedrate limits.
    iv. Good Combustion: Combustion Zone Temperature. As combustion 
zone temperatures decrease, combustion efficiency can decrease 
resulting in an increase in formation of (or incomplete destruction of) 
D/F precursors. For this reason, the Agency proposes limiting 
combustion zone temperature in each

[[Page 17423]]

chamber to the minimum level occurring during the comprehensive 
performance test documenting compliance with the D/F standard.
    BIFs and incinerators are already required to monitor combustion 
zone temperature for compliance with metals emissions standards and 
destruction and removal efficiency (DRE). Monitoring of combustion zone 
temperature has been problematic, however, because the actual burning 
zone temperature cannot be measured at many units (e.g., cement kilns). 
For this reason, the BIF rule requires measurement of the ``combustion 
chamber temperature where the temperature measurement is as close to 
the combustion zone as possible.'' See Sec. 266.103(c)(1)(vii).
    In some cases, temperature is measured at a location quite removed 
from the combustion zone due to extreme temperatures and the harsh 
conditions at the combustion zone. We are concerned that monitoring at 
such remote locations may not accurately reflect changes in combustion 
zone temperatures. For example, a reduction in heat transfer chain in a 
wet cement kiln due to wear over time or decreasing raw material 
feedrate (at a fixed heat input) in a cement or lightweight aggregate 
kiln may increase temperature at the kiln outlet even if combustion 
conditions actually caused a decrease in combustion zone temperature.
    We specifically invite comment on how to address this issue. For 
example, the final rule could require the owner or operator to identify 
a parameter that correlates with combustion zone temperature and to 
provide data or information to support the use of that parameter in the 
operating record. The final rule could also enable the Director on a 
case-specific basis to require the use of alternate parameters as 
deemed appropriate, or to determine that there is no practicable 
approach to ensure that minimum combustion chamber temperature is 
maintained. In that case, the Director may determine that the source 
could not comply with the regulations and, thus, could not burn 
hazardous waste.
    Note also that, in the final rule, we would revise the existing BIF 
and incinerator rules to conform with the approach used in the final 
MACT rule. Those conforming revisions would become effective six months 
from the date of publication of the final rule in the Federal Register 
and would remain in effect until the MACT standards take effect.
    The temperature limit(s) would apply to each combustion zone into 
which hazardous waste is fired. As examples, for incinerators with a 
primary and secondary chamber, separate limits would be established for 
the combustion zone in each chamber. For kilns, separate temperature 
limits would apply at each location where hazardous waste may be fired 
(e.g., the hot end where clinker is discharged; the mid-point of the 
kiln; and the cold end of the kiln where raw material is fed).
    EPA proposes that a ten-minute average be used to control 
perturbations in combustion chamber temperature and that an hourly 
rolling average be used to control average combustion chamber 
temperature. The ten-minute average would be established as the average 
of the minimum ten-minute rolling average for each run of the 
comprehensive performance test. The hourly average would be established 
as the average over all runs.
    v. Good Combustion: Maximum Flue Gas Rate or Production Rate. Flue 
gas flowrates in excess of those that occur during performance testing 
reduce the time that combustion gases are exposed to combustion chamber 
temperatures. Thus, combustion efficiency can decrease causing an 
increase in D/F precursors.141 Accordingly, today's rule would 
limit flue gas flowrate based on levels that occur during the 
comprehensive performance test.
---------------------------------------------------------------------------

    \141\ We note that an increase in gas flow rate can also 
adversely affect the performance of a D/F emission control device 
(e.g., carbon injection, catalytic oxidizer). Thus, gas flow rate is 
controlled for this reason as well.
---------------------------------------------------------------------------

    For CKs and LWAKs, the rule would allow the use of production rate 
as a surrogate for flue gas flowrate. This is the approach currently 
used for the BIF rule for these devices, given that flue gas flowrate 
correlates with production rate (e.g., feedrate of raw materials or 
rate of production of clinker or aggregate). However, production rate 
may not relate well to flue gas flowrate in situations where the 
moisture content of the feed to the combustor changes dramatically. 
Therefore, EPA invites comment on how to address moisture content in 
feeds.
    The gas flowrate or production rate limit would be established as 
the average of the maximum hourly rolling average for each run of the 
comprehensive performance test.
    vi. Good Combustion: Batch Size, Feeding Frequency, and Minimum 
Oxygen. Some HWCs burn waste or non-waste fuel in batches, such as 
metal drums or plastic containers. Some containerized waste can 
volatilize rapidly, causing a momentary oxygen-deficient condition that 
can result in an increase in D/F precursors.142 To ensure that D/F 
precursors are not increased over levels that occur during the 
comprehensive performance test, the rule would establish site-specific 
limits on maximum batch size, batch feeding frequency, and minimum 
oxygen concentration at the end of the combustion chamber into which 
the batch is fed, at the time the batch is fed.143
---------------------------------------------------------------------------

    \142\ The requirements would apply when either hazardous or non-
hazardous waste fuels are batch fed because the potential for 
oxygen-deficient conditions and an increase in D/F precursors is 
present irrespective of whether the material fed is classified as a 
hazardous waste.
    \143\ EPA considered whether it would be practical to establish 
a national minimum oxygen level for all HWCs in this proposed rule 
and believes it is not practical. A limit on minimum oxygen content 
would have to be established on a case-specific basis given that the 
minimum oxygen level necessary for good combustion will vary from 
source to source within a given source category, and will vary 
within a given source over time as the type or volume of waste or 
fuel varies. The Agency invites comment on whether the final rule 
should require a case-specific limit on minimum oxygen content for 
all HWCs rather than as proposed for only batch-fired HWCs. If so, 
the limits would be established on a ten-minute and an hourly 
rolling average as proposed for combustion chamber temperature.
---------------------------------------------------------------------------

    This requirement would apply to all HWCs that burn any waste or 
non-waste fuel in batches (i.e., ram or equivalent feed systems) or 
containers. For example, incinerators that use a ram to charge batches 
of hazardous or nonhazardous waste would be subject to these 
requirements. Cement kilns that feed containers of fuel at mid-kiln or 
at the ``cold'', raw material feed end would also be subject to these 
requirements, as would hazardous waste-burning cement kilns that feed 
tires in batches.
    The rule would provide a conditioned exemption from the (site-
specific) oxygen limit, however, for cement kilns that feed up to 1-
gallon containers into the ``hot'', clinker discharge of the kiln. We 
do not believe that it is necessary to control the oxygen content of 
combustion gases when these containers are fed into the hot end of the 
kiln given that the oxygen demand from waste in the containers would be 
insignificant compared to the oxygen demand from other (non-
containerized) fuel burned at this location. The frequency of firing 
the containers would, however, be limited to the rate occurring during 
the performance test.
    There would be no averaging period associated with the limits on 
these operating parameters. The maximum batch size a facility could 
burn during normal operations would be limited by mass and would be 
established based on the container or batch fired during the test 
having the lowest mass. The minimum batch feeding interval (i.e., the 
minimum period of time between batch feedings) a facility could burn

[[Page 17424]]

during normal operations would be established as the longest interval 
of time between batch feedings during the comprehensive performance 
test. The minimum oxygen content at which a facility would charge a 
containerized waste into the burner during normal operations would be 
the highest instantaneous oxygen level observed when any batch was fed 
during the comprehensive performance test.
    EPA specifically invites comment on whether the bases of these 
three parameters are overly conservative. Rather than basing maximum 
batch size on the smallest container fed during the comprehensive test, 
EPA could establish maximum batch size based on the average container 
mass. Feeding frequency could be based on the average time interval 
between batches during the comprehensive test. Oxygen concentration 
could be the average oxygen level occurring during the test. To address 
this issue, EPA needs to know whether the proposed requirements are 
overly conservative and why, or conversely, whether the options 
described in this paragraph are not restrictive enough.
    EPA specifically invites comment on other approaches to establish 
limits for these parameters, and whether (and how) it would be 
necessary to limit maximum volatility of the batch-fired material.
    vii. Dry PM Collection Device Inlet Temperature. Formation of D/F 
emissions on particulate matter increases with increasing temperature. 
Above 350 deg.F and up to approximately 700 deg.F, emissions of D/F can 
increase a factor of 10 for every 125 deg.F increase in 
temperature.144 Consequently, today's rule would limit temperature 
at the inlet to a dry PM control device to the maximum levels that 
occurred during the comprehensive performance test.
---------------------------------------------------------------------------

    \144\ See Chapter 7.2 of ``Draft Technical Support Document for 
HWC MACT Standards, Volume IV: Compliance with the Proposed MACT 
Standards'', February 1996.
---------------------------------------------------------------------------

    It is proposed that a ten-minute rolling average be used to control 
perturbations in temperatures and that a one-hour rolling average be 
used to control the average temperature. The ten-minute rolling average 
limit would be established as the average of the highest ten-minute 
average for each run. The hourly average would be established as the 
average of over all runs.
    viii. Carbon Injection. Facilities may use carbon injection to meet 
the D/F standard. Today's rule would limit the following carbon 
injection parameters: minimum carbon injection rate; minimum carrier 
fluid flowrate or nozzle pressure drop, and adsorption characteristics 
of the carbon.
    A minimum carbon feedrate limit is necessary to ensure that 
facilities maintain the same D/F removal efficiency as was demonstrated 
during the comprehensive performance test. It is proposed that minimum 
carbon injection rate be maintained on a ten-minute and one-hour 
average. The ten-minute average would be established as the average of 
the minimum 10-minute rolling average for each run, and the one-hour 
average would be established as the average over all runs.
    A carrier fluid, gas or liquid, is necessary to transport and 
inject the carbon into the gas stream. EPA proposes that either minimum 
carrier gas flowrate or pressure drop across the nozzle be maintained 
to ensure good flow of the injected carbon into the flue gas stream. It 
is proposed that either limit be established on a 10-minute rolling 
average and that the limit be based on the carbon injection 
manufacturers specifications.
    Finally, to ensure that D/F removal efficiency is maintained after 
the performance test, carbon used after the test must have the same or 
better adsorption properties as carbon used during the test. Thus, the 
rule would require that facilities continue to use the same brand and 
type of carbon that was used during the comprehensive test. The rule 
would allow a source to obtain a waiver from this requirement from the 
Director, however, if the owner or operator: (1) documents by data or 
information key characteristics of carbon which affect removal of D/F 
from combustion gas; (2) documents by data or information specification 
levels corresponding to those characteristics; and (3) complies with 
the specification.
    ix. Carbon Bed. Some sources may elect to use a carbon bed to 
control D/F. Today's rule would limit the age of the carbon and the 
adsorption characteristics of the carbon to ensure that D/F control is 
maintained.
    Since carbon beds work by adsorbing certain chemicals, e.g., dioxin 
and mercury, and the carbon in the bed becomes less effective as the 
active sites for adsorption become occupied, an appropriate control 
parameter for carbon beds is the amount of time the carbon in use. EPA 
is particularly concerned about a facility's ability to know when a 
carbon bed is spent, i.e., when enough active sites get occupied to 
make the device inadequate for removing dioxin or mercury, and knowing 
how often carbon must be replaced from the bed to ensure this does not 
occur. This cannot be determined during the initial comprehensive 
performance test. For that reason, the Agency proposes that facilities 
follow the carbon bed manufacturer's specifications for the initial 
comprehensive performance test.
    No carbon aging would be required for this initial test. For 
confirmatory tests, facilities would be required to follow the normal 
change-out schedule specified by the manufacturer. For subsequent 
comprehensive tests, the Agency proposes that the D/F test be conducted 
at maximum carbon age, i.e., at the least frequent carbon change-out, 
and that this age be maximum age allowable under normal operation.
    Alternately, the Agency could use some form of a breakthrough 
calculation and use this to assure compliance with the D/F standard. A 
breakthrough calculation would give a theoretical minimum carbon 
change-out schedule which the facility could use to ensure that 
breakthrough, i.e., the dramatic reduction in efficiency of the carbon 
bed due to too make active sites being occupied, does not happen. 
However a breakthrough calculation can only be done after 
experimentation determines the relationship between incoming adsorbed 
chemicals and the adsorption rate of the carbon. The adsorption rate of 
carbon can be determined experimentally, but the speciation of adsorbed 
chemicals in a flue gas stream is site-specific and may vary greatly 
within a given site over time. Therefore, EPA proposes using this 
alternative only for the initial comprehensive test, when site data is 
not available and the carbon bed is not aged. EPA believes that, for 
subsequent comprehensive tests, the proposed option is preferable, 
since it provides for the setting of the minimum carbon change-out on 
subsequent D/F tests. EPA does not believe it is appropriate to use 
breakthrough calculations for the second and subsequent comprehensive 
test(s) since they do not take into account facility specific 
characteristics, like the concentration of adsorbed chemicals in the 
flue gas. EPA invites comment on an approach which would use 
breakthrough calculations alone, to see if it can become workable in 
another form than the Agency has envisioned.
    An issue that is difficult to address is that carbon age is 
dependant not only on time in service, but also the carbon bed inlet 
concentration of substances (e.g., metals, PM) which adsorb or absorb 
onto the carbon. There may be other factors that affect D/F removal 
efficiency of the bed. The Agency invites comment on how to address 
these issues.

[[Page 17425]]

    Another issue is whether it is necessary to control temperature at 
the inlet to the carbon bed. EPA does not believe this is necessary 
since facilities will need a PM control device upstream of a carbon bed 
and temperature at the inlet to dry PM APCDs is proposed to be 
controlled. However, the consequences of a temperature spike at the 
carbon bed can be severe: a temperature spike may cause adsorbed D/F 
and Hg to de-adsorb and re-enter the gas stream, resulting in a 
significant amount of D/F and Hg being emitted at the stack at once. 
For this reason, the Agency invites comment on whether controlling 
temperature at the inlet to a carbon bed is necessary.
    Finally, as the case with carbon injection, to ensure that D/F 
removal efficiency is maintained after the performance test, carbon 
used post-test must have the same or better adsorption properties as 
carbon used during the test. Thus, the rule would require that 
facilities continue to use the same brand and type of carbon as was 
used during the comprehensive test. The rule would allow a source to 
obtain a waiver from this requirement, however, as discussed above.
    x. Catalytic Oxidizer. Some facilities may use a catalytic oxidizer 
to meet the D/F standard. Catalytic oxidizers used to control stack 
emissions are similar to those used in automotive and industrial 
applications. The flue gas passes over a catalytic metals, such as 
palladium and platinum, supported by an alumina washcoat on some metal 
or ceramic substrate. When the flue gas passes through the catalyst, a 
reaction takes place similar to combustion, converting hydrocarbons to 
carbon monoxide, then carbon dioxide. Catalytic oxidizers can also be 
``poisoned'' by lead and other metals just as automotive and industrial 
catalysts are.
    The rule would require sources to establish site-specific limits on 
the following operating parameters for catalytic oxidizers: minimum 
flue gas temperature at the inlet of the catalyst, maximum age in use, 
catalyst replacement specifications, and maximum flue gas temperature 
at the inlet of the catalyst. The rule would allow a waiver from these 
provisions if the owner documents to the Director that establishing 
limits on other operating parameters would be more appropriate to 
ensure that the D/F destruction efficiency of the oxidizer is 
maintained after the performance test. The owner or operator would 
provide such documentation, including how limits on the alternative 
operating parameters would be established and appropriate averaging 
periods, and a request for a waiver as part of the notification to 
conduct the comprehensive performance test and draft test protocol. The 
Director would grant the waiver in writing, if warranted.
    Minimum flue gas temperature at the inlet of the catalyst is 
necessary to ensure that the catalyst is above light-off temperature. 
Light-off temperature is that minimum temperature at which the catalyst 
is hot enough to catalyze the reactions of hydrocarbons and carbon 
monoxide. EPA proposes that minimum flue gas temperature be maintained 
on both a ten-minute and one-hour average. The ten-minute average limit 
would be established as the average of the minimum ten-minute rolling 
average for each run during the comprehensive performance test. The 
hourly average limit would be established as the average hourly average 
over all runs.
    Due to poisoning and general degradation of the catalyst, 
manufacturers often establish a maximum time in-use for the catalyst. 
EPA proposes that the manufacturer's specification for maximum age be 
used as maximum age of the catalyst.
    When a catalyst is replaced, it must be of the same design of the 
previous catalyst to ensure that the replacement catalyst will work as 
efficiently as the previous one. Therefore, EPA proposes that the 
following design parameters be used in specifying replacement 
catalysts: loading of catalytic metals; space time; and monolith 
substrate construction.
    Catalytic metal loading is important because, without sufficient 
catalytic metal on the catalyst, it would not properly function. Also, 
some catalytic metals are more efficient than others. Therefore, EPA 
proposes that replacement catalysts have at least the same catalytic 
metal loading for each catalytic metal as the catalyst used during the 
comprehensive performance test.
    Space time, expressed in inverse seconds (s-1), is defined as 
the maximum rated volumetric flow through the catalyst divided by the 
volume of the catalyst. This is important because it is a measure of 
the gas flow residence time and, hence, the amount of time the flue gas 
is in the catalyst. The longer the gas is in the catalyst, the more 
time the catalyst has to cause hydrocarbons and carbon monoxide to 
react. It is proposed that replacement catalysts have at the same or 
lower space time as the one used during the comprehensive performance 
test.
    Substrate construction is also an important parameter. Substrates 
for industrial applications are typically monoliths, made of rippled 
metal plates banded together around the circumference of the catalyst. 
Ceramic monoliths and pellets can also be used. Because of the many 
types of substrates, EPA proposes that the same materials of 
construction, monolith or pellets and metal or ceramic, be used as was 
used during the comprehensive performance test. Monoliths also form a 
honeycomb like structure when viewed from one end. The pore density, 
i.e., number of pores per square inch, is critical because they must be 
small enough to ensure intimate contact between the flue gas and the 
catalyst, but large enough to allow unrestricted flow through the 
catalyst. Therefore, if a monolith substrate is used, EPA proposes that 
the same pore density as the one used during the comprehensive 
performance test. Finally, catalysts are supported by a washcoat, 
typically alumina. EPA proposes that replacement catalysts have the 
same type and loading of washcoat as was on the catalyst used during 
the comprehensive performance test.
    Finally, EPA believes it is also important to control maximum flue 
gas temperature into the catalyst. This is because sustained high flue 
gas temperature can result in sintering of the catalyst, degrading its 
performance. The Agency proposes that maximum flue gas temperature into 
the catalyst be controlled and that it be a ten-minute rolling average, 
based on manufacturer specifications.
    xi. D/F Inhibitor. Some facilities may use a D/F inhibitor (e.g., 
sulfur) to meet the D/F standard. In such cases, the rule would 
establish a minimum inhibitor feedrate. Limits would be established on 
both a ten-minute and one-hour average. The ten-minute average limit 
would be established as the average of the minimum ten-minute rolling 
average for each run, and the one-hour average limit would be 
established as the average over all runs. See also the discussion in 
section II.F.2 below for other requirements to document compliance with 
feedrate limits.
    This minimum inhibitor feedrate pertains to additives to 
feedstreams, not naturally occurring inhibitors that may be found in 
fossil fuels or hazardous waste. It is conceivable that a facility 
would choose to burn high sulfur fuel or waste specially during the 
comprehensive test and switch back to low sulfur fuels or waste after 
the test, thus reducing D/F emissions during the comprehensive test to 
levels that would not be maintained after the test. EPA invites comment 
on whether and how to address this concern, including whether it would 
be appropriate to establish

[[Page 17426]]

limits on the amount of naturally occurring inhibitor, either during 
performance testing or as an operating limit. Comments and 
documentation are also requested to help identify such inhibitors.
    As was the case with carbon used in carbon injection and carbon 
beds, EPA is concerned that facilities may use a less effective, and 
presumably less expensive, D/F inhibitor during normal operation than 
was used during the comprehensive performance test. For this reason, 
the rule would require that facilities continue to use the same type 
and brand of inhibitor as was used during the comprehensive test. The 
rule would allow a source to obtain a waiver from this requirement from 
the Director, however, if the owner or operator: (1) documents by data 
or information key characteristics of the inhibitor which inhibit 
formation of D/F; (2) documents by data or information specification 
levels corresponding to those characteristics; and (3) complies with 
the specification.
    xii. Rapid Quench. Some facilities may elect to use a rapid quench 
to lower flue gas temperature to meet the D/F standard. The rule would 
not establish limits on operating parameters for rapid quench systems 
because we believe that a maximum dry PM control device temperature is 
sufficient to ensure that the quench was adequate. We note, however, 
that a facility may use a rapid quench for control of D/F emissions yet 
not have a dry PM control device. One way to address this situation is 
to require that a maximum flue gas temperature be established at the 
stack.
    EPA doubts, however, that there will be any facilities which use a 
rapid quench without a dry PM control device. Consequently, we invite 
comment on whether the final rule should establish a maximum flue gas 
temperature limit that would address such apparently hypothetical 
situations.
    xiii. Consideration of Feed Restrictions on Metals, Halogens, and 
Dioxin Precursors. The rule would not establish feedrate limits on 
metals, halogens, or D/F precursors to ensure compliance with the D/F 
standard. Some research indicates that certain metals, copper for 
instance, in the feed may catalyze the formation of D/F. However, this 
research is inconclusive and there is not yet a consensus among the 
research community that catalytic metal in the feed necessarily causes 
increased D/F emissions.145 Therefore, EPA proposes not limiting 
the feed of catalytic metals in the feed.
---------------------------------------------------------------------------

    \145\ See Chapter 7.2 of USEPA, ``Draft Technical Support 
Document for HWC MACT Standards, Volume IV: Compliance with the 
Proposed MACT Standards'', February 1996.
---------------------------------------------------------------------------

    Research and common sense has also indicated that the presence of 
halogens, such as chlorine, in the feed may contribute to the 
production of halogenated D/F. While the presence of chlorine in the 
feed is necessary for the formation of chlorinated D/F, current science 
seems to support the view that there is not a clear correlation between 
the level of chlorine in the feed and the level of dioxin in the flue 
gas. In other words, increasing halogen feedrate above de minimis 
levels does not appear to cause increased emissions of chlorinated D/
F.146 Therefore, the rule would not limit the amount of chlorine 
fed to ensure compliance with the D/F standard, particularly in light 
of the suite of other compliance assurance measures.
---------------------------------------------------------------------------

    \146\ See Chapter 7.3 of USEPA, ``Draft Technical Support 
Document for HWC MACT Standards, Volume IV: Compliance with the 
Proposed MACT Standards'', February 1996.
---------------------------------------------------------------------------

    Nonetheless, we believe that it is prudent to require that chlorine 
be fed at normal levels (or greater) during the D/F comprehensive 
performance test. This is because, while more chlorine does not 
necessarily form more dioxin, some chlorine is needed to form 
chlorinated D/F. We invite comment on how to ensure that normal levels 
of chlorine are fed during the comprehensive performance test. For 
sources that do not elect to use a CEMS for SVM, LVM, HCl and Cl2 
and, thus, must maximize chlorine feedrate during the test, this is not 
an issue. We believe that the vast majority of sources will be in this 
situation. For sources that elect to use such CEMS (assuming that 
multi-metal and Cl2 CEMS become commercially available), defining 
normal chlorine feedrates is an issue.
    Some arguments have been made that the presence of organic dioxin 
precursors in the feed would result in an increased level of D/F in the 
flue gas. EPA has briefly examined certain facilities which feed dioxin 
or known organic dioxin precursors (e.g., chlorophenol and 
chlorobenzene) to those which are known not to feed organic dioxin 
precursors. Although our limited study suggests that no strong 
correlation exists between the level of dioxins or organic dioxin 
precursors in the feed and D/F emissions, we do not believe the issue 
has been sufficiently examined in detail (indeed, other evidence 
suggests that a correlation might exist). EPA invites comment on 
whether feed restrictions on D/F and organic dioxin precursors are 
warranted and, if so, whether this should be an operating parameter or 
a feed requirement during the comprehensive test (such as proposed for 
chlorine).
3. Mercury (Hg)
    Table V.2.3 Summarizes the proposed compliance monitoring 
requirements and other options being considered for Hg. See also 
proposed Sec. 63.1210(k).

                                  Table V.2.3.--Proposed Hg Monitoring Requirements and Other Options Being Considered                                  
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                    Operating limit avg 
                                                                Compliance using          Limits from            Avg. period              pd basis      
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed Requirement...............  CEMS..................  Total Hg or Multi-      CEMS Std.............  10 hour..............                       
                                                              metal CEMS.                                                                               
Option 1: Elemental Hg CEMS........  Surrogate CEMS........  Elemental Hg CEMS.....  Comp Test............  10 hour..............  Avg over all runs.   
                                     Max Flue Gas Flowrate   Same..................  Comp Test............  1 hour...............  Avg of Max 1 hour    
                                      or Production Rate.                                                                           RAs.                
                                     Min Press Drop, Wet     Pressure Drop Across    Comp Test............  10 min...............  Avg of Min 10 min    
                                      Scrubber.               Scrubber.                                                             RAs.                
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Liq Feed Press,     Pressure..............  Manuf Spec...........  10 min...............                       
                                      Wet Scrubber.                                                                                                     
                                     Min Liq pH............  pH....................  Comp Test............  10 min...............  Avg of Min 10 min    
                                                                                                                                    RAs.                

[[Page 17427]]

                                                                                                                                                        
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Liq/Gas Ratio, Wet  Scrubber Liquid and     Comp Test............  10 min...............  Avg of Min 10 min    
                                      Scrubber.               Flue Gas Flowrate.                                                    RAs.                
                                                                                                            1 hour...............  Avg over all runs.   
Option 2: No CEMS..................  Max Total Hg Feedrate,  Feedstream Analysis...  Comp Test............  12 hour..............  Avg over all runs.   
                                      all streams.                                                                                                      
                                     Max Inlet Temp to Dry   Temp..................  Comp Test............  10 min...............  Avg of Max 10 min    
                                      PM APCD.                                                                                      RAs.                
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Carbon Injection    Feedrate CMS..........  Comp Test............  10 min...............  Avg of Min 10 min    
                                      Rate.                                                                                         RAs.                
                                                                                                            1 hour...............  Avg over all runs.   
                                     Carbon Specs..........  Brand and Type........  Comp Test............  N/A..................  N/A.                 
                                     Min Carrier Fluid       Same..................  Manuf Spec...........  10 min...............  N/A                  
                                      Flowrate or Nozzle.                                                                                               
                                     Max Carbon Age........  Max Carbon............  Initia...............  N/A..................  Manuf Specs.         
                                                                                     Conf Tests...........  N/A..................  Normal C Change-out  
                                                                                                                                    Schedule.           
                                                                                     Subsequent Comp Tests  N/A..................  Max C Age is the age 
                                                                                                                                    during subsequent   
                                                                                                                                    Comp Tests.         
                                     Max Flue Gas Flowrate   Flowrate CMS or         Comp Test............  1 hour...............  Avg of Max 1 hour    
                                      of Production Rate.     Production Rate.                                                      RAs.                
                                     Min Press Drop, Wet     Pressure Drop Across    Comp Test............  10 min...............  Avg of Min 10 min    
                                      Scrubber.               Scrubber.                                                             RAs.                
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Liq Feed Press,     Pressure..............  Manuf Spec...........  10 min...............                       
                                      Wet Scrubber.                                                                                                     
                                     Min Liq pH, Wet         pH....................  Comp Test............  10 min...............  Avg of Min 10 min    
                                      Scrubber.                                                                                     RAs.                
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Liq/Gas Ratio, Wet  Scrubber Liquid and     Comp Test............  10 min...............  Avg of Min 10 min    
                                      Scrubber.               Flue Gas Flowrate.                                                    RAs.                
                                                                                                            1 hour...............  Avg over all runs.   
--------------------------------------------------------------------------------------------------------------------------------------------------------



    a. Evaluation of Monitoring Options. Several types of CEMS exist or 
are under development which measure Hg. Therefore, the rule proposes 
use of a Hg CEMS to document compliance with the Hg standard.147
---------------------------------------------------------------------------

    \147\ In February 1996, the Agency initiated a demonstration 
program to determine whether Hg (and PM) CEMS can comply with the 
performance specifications proposed today. The demonstration will 
also evaluate long-term durability (e.g., 6 months or longer) of the 
CEMS. Results of the demonstration will be made available for review 
and comment prior to promulgation of the final rule.
---------------------------------------------------------------------------

    The rule would allow two alternative CEMS approaches: the use of a 
multi-metal CEMS or the use of a total Hg CEMS. (In addition, we 
discuss below our concerns with allowing the use of an elemental Hg 
CEMS.) If a facility elects to use a multi-metal (MM) CEMS for 
compliance with the SVM and LVM standards, the MM CEMS can be used for 
compliance with the Hg standard as well. See the discussion below on 
SVMs and LVMs for discussion on MM CEMS. If a facility elects not to 
use a MM CEMS, the source may use a total Hg CEMS.
    In case the final rule does not require compliance with the Hg 
standard using a CEMS, we also invite comment on ensuring compliance by 
establishing limits on operating parameters.
    b. Total Mercury CEMS. The rule would require use of a CEMS to 
monitor Hg emissions (see below, small-on site sources could obtain a 
waiver from the CEMS requirement.) If a facility elects not to use a MM 
CEMS for compliance with all of the metals standards, EPA recommends 
that facilities use a total Hg CEMS.
    An example of such a unit is a total Hg CEMS made by the German 
company Verewa and marketed in the US by Euramark. The device has 
recently been certified by TUV, a quasi-governmental German agency 
charged with approving compliance devices and methods. The CEMS uses 
wet chemistry techniques prior to an elemental Hg UV absorption 
analyzer to convert all species of Hg into elemental Hg. The analyzer 
then determines the total Hg in the flue gas.
    The performance specification for a total Hg CEMS are proposed here 
as Part 60, Appendix B, Performance Specification 12. In addition, the 
appendix to Part 63, Subpart EEE, Quality Assurance for CEMS would 
require quarterly testing of the analyzer and relative accuracy testing 
of the total system every 3 years (or 5 years for small on-site 
facilities).
    Also, EPA invites comments on allowing small on-site sources 
(defined in Sec. 63.1208(b)(1)(ii) in the proposed regulations) to 
obtain a waiver from the requirement of installing Hg CEMS. If the 
waiver is promulgated and granted by the permitting authority, the 
facility would demonstrate compliance with the Hg standard by 
establishing operating parameter limits described in subsection d, 
``Alternative to a CEMS,'' below.
    c. Elemental Mercury CEMS. EPA invites comment on another approach 
to continuously monitor Hg emissions, the use of an elemental Hg CEMS. 
Although the elemental Hg CEMS may be less expensive than a total Hg 
CEMS, EPA has several concerns with allowing the use of an elemental Hg 
CEMS.
    An elemental Hg CEMS does not measure species other than elemental, 
or metallic Hg. It does not measure Hg

[[Page 17428]]

salts such as mercuric chloride (HgCl2). Therefore, it would be 
necessary for the facility to measure elemental Hg using the CEMS and 
elemental and Hg salts separately using manual methods during the 
comprehensive performance test.
    Data from the comprehensive test would be used to identify the 
elemental Hg emission level at which the facility is considered to be 
in compliance with the total Hg standard. However, following the 
comprehensive test a facility could have higher levels of undetectable 
Hg salt emissions than occurred during the comprehensive test. This 
could happen in one of two ways: the scrubber may not be working as 
effectively; or the Hg and halogen feed may have increased such that, 
at a fixed scrubber efficiency, more Hg salts are emitted as a result. 
Ensuring that the scrubber efficiency is maintained at performance test 
levels can be accomplished using the parameters described above. 
However, it is difficult to determine whether the same amount of Hg 
salts, relative to the amount of total Hg, is being emitted. One could 
correlate Hg and halogen feed with scrubber efficiency at various 
scrubber conditions, but this would require many data points and seems 
infeasible from a monetary and technical standpoint. Even if an 
approach can be developed, the Agency is inclined to believe it would 
require a lot of oversight to ensure it is done properly.
    If the issue of correlating total Hg emissions to an elemental Hg 
CEMS can be successfully addressed, establishing the site-specific 
limit and the averaging period for the elemental Hg standard would then 
have to be addressed. Facilities would be able to use the mean of the 
results during the test, along with a variability factor, as their 
site-specific elemental Hg level. The averaging period could be the 
time duration of three runs of the comprehensive performance test, but 
manual methods tests do not end on the exact hour and there may be more 
than one comprehensive test with, likely, different sampling periods. 
So, a problem would arise as to what averaging period to use.
    For these reasons, EPA believes the use of an elemental Hg CEMS is 
infeasible to implement under self-implemented MACT standards. 
Nonetheless, if these issues can be resolved, the final rule may allow 
some use of an elemental Hg CEMS.
    d. Alternative to a CEMS. If the final rule does not require that 
Hg emissions be continuously monitored, the rule would ensure 
compliance with the Hg standard by establishing limits on operating 
parameters. Also if the provision allowing small on-site facilities 
(defined in Sec. 63.1208(b)(1)(ii) of the proposed regulations) to 
waive the Hg CEMS requirement is promulgated and such a facility elects 
not to use an Hg CEMS, the facility would have to establish these 
operating parameter limits to document compliance with the Hg standard. 
The proposed operating limits are: maximum Hg feedrate, Hg scrubber 
operating parameters, maximum flue gas feedrate, minimum carbon 
injection rate, and carbon bed operating parameters.
    i. Maximum Hg Feedrates. Absent a requirement to monitor Hg 
emissions with a CEMS, the final rule would establish a maximum Hg 
feedrate limit. This is because the amount of Hg fed into the combustor 
directly affects emissions and the ability of control equipment to 
remove Hg. This maximum feedrate pertains to all feeds into the 
combustor: hazardous waste, raw materials, additives, and fossil fuels. 
Feedrate sampling and analysis protocols would be described in the 
facility's waste analysis plan. The limit would be based on a twelve-
hour average and established as twelve times the hourly average 
feedrate during all runs of the comprehensive performance test. See 
also the discussion in section II.F.2. below for other requirements to 
document compliance with feedrate limits.
    As mentioned above in Subsection B, this twelve-hour average is 
inconsistent with the ten hour averaging period for metals CEMS. CEMS 
should have longer averaging periods than operating parameters such as 
feedrates. Therefore, EPA invites comment on whether the averaging 
period for Hg feedrate should be promulgated at six, instead of 12, 
hours. EPA believes a six-hour averaging period for Hg feedrate is 
sufficiently conservative, relative to the CEMS averaging period and 
achievable.
    ii. Max Inlet Temp to Dry PM APCD. High inlet temperatures to dry 
PM APCDs can cause low recovery of Hg in the APCD. This is because Hg 
volatility increases with increasing temperature. Therefore, absent a 
requirement to monitor Hg emissions with a CEMS, the final rule would 
control inlet temperature to a dry PM APCD. Limits would be based on 
both a 10-minute and a one-hour average. The 10-minute average would be 
the average of the maximum PM APCD inlet temperatures experienced 
during each compliance test run and the one-hour average would be the 
average over all runs.
    iii. Carbon Injection. Some facilities may need to use carbon 
injection as an aftertreatment to comply with the Hg standard. Absent a 
Hg CEMS requirement, the final rule would establish controls on the 
following carbon injection operating parameters: minimum carbon 
injection rate, carbon specifications, and minimum carrier flowrate or 
nozzle pressure drop. The controls would be established under the same 
approach as proposed for carbon injection used for D/F control. See the 
previous discussion.
    iv. Carbon Bed. Rather than carbon injection, some facilities may 
elect to use a carbon bed to control Hg emissions. Absent a requirement 
to monitor Hg emissions with a CEMS, the final rule would establish 
controls on carbon bed operating parameters under the same approach as 
proposed for carbon beds used for D/F control. See the previous 
discussion.
    v. Maximum Flue Gas Flowrate or Production Rate. As discussed above 
for compliance with the D/F standard, an increase in flue gas flowrate 
can decrease collection efficiency of the emission control device. 
Accordingly, absent a requirement to monitor Hg emissions continuously, 
the final rule would limit flue gas flowrate or production rate under 
the same approach as proposed for D/F compliance. See the previous 
discussion.
    vi. Wet Scrubber Parameters. The efficiency of wet scrubbers 
directly affects the removal of Hg salts from flue gas. Key operating 
parameters would include: maximum flue gas flowrate or production rate, 
minimum pressure drop across the wet scrubber, minimum liquid feed 
pressure, minimum liquid pH, and minimum liquid to gas ratio. Refer to 
the section below on compliance requirements for the HCl and Cl2 
standard for discussion on these parameters. Absent a requirement to 
monitor Hg emissions continuously, the final rule would establish 
limits on these parameters under the same approach as proposed for 
compliance with the HCl and Cl2 standard.
4. Semivolatile Metals (SVM) and Low Volatile Metals (LVM)
    Table V.2.4 Summarizes the proposed compliance monitoring 
requirements and other options being considered. See also proposed 
Sec. 63.1210 (l) and (m).

[[Page 17429]]



                   Table V.2.4.--Summary of Proposed SVM and LVM Compliance Monitoring Requirements and Other Options Being Considered                  
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                    Operating limit avg 
                                                                Compliance using           Limit from             Avg period              pd basis      
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed Option 1 (Facility Choice)  CEMS..................  Multi-metal CEMS......  CEMS Std.............  10 hour..............                       
Proposed Option 2 (Facility Choice)  Good PM Control.......  PM CEMS (see PM for     Comp Test............  10 min...............  Avg of Max 10 min    
                                                              Others).                                                              RAs.                
                                                                                                            1 hour...............  Avg over all runs.   
                                     Max Inlet Temp to Dry   Same..................  Comp Test............  10 min...............  Avg of Max 10 min    
                                      PM APCD.                                                                                      RAs.                
                                                                                                            1 hour...............  Avg over all runs.   
                                     Max Total SVM and LVM   Feedstream Analysis...  Comp Test............  12 hour..............  Avg over all runs.   
                                      Feedrates.                                                                                                        
                                     Max Pumpable LVM        Feedstream Analysis...  Comp Test............  12 hour..............  Avg over all runs.   
                                      Feedrate.                                                                                                         
                                     Max Chlorine Feedrate.  Feedstream Analysis...  Comp Test............  12 hour..............  Avg over all runs.   
--------------------------------------------------------------------------------------------------------------------------------------------------------

    a. Evaluation of Monitoring Options. EPA proposes two compliance 
options for the SVM and LVM standards: use of a multi-metal CEMS (MM 
CEMS) or compliance with limits on operating parameters. A facility 
would be allowed to use either of these options to demonstrate 
compliance. We are not proposing to require the use of a CEMS because a 
CEMS is not commercially available for LVMs and SVMs at this time, and 
the Agency is uncertain whether a CEMS that could meet the proposed 
performance specifications discussed below would be available at 
promulgation of the final rule.
    b. Option 1: Use of a Multi-metal CEMS to Document Compliance. EPA 
is proposing to allow the use of a MM CEMS for compliance with the Hg, 
SVM, and LVM standards. If a facility elects to use a MM CEMS, limits 
on operating parameters would not be required.148
---------------------------------------------------------------------------

    \148\ Although a site-specific limit on PM would also not be 
required for compliance with the SVM and LVM emission standards, it 
would be needed to comply with the D/F standard.
---------------------------------------------------------------------------

    EPA is proposing to allow the use of a MM CEMS (and may require the 
use of MM CEMS if they would be commercially available by the 
promulgation date of the final rule) because it is difficult to ensure 
compliance with the emission standards by limiting operating 
parameters. Sampling and analysis of feedstreams to monitor metals 
feedrate has drawbacks in that representative sampling is sometimes 
difficult and expensive to achieve,149 and the available 
analytical methods may not extract all metals from some feedstreams 
(and thus metal feedrates may be higher than indicated by analysis). In 
addition, it is often difficult to use limits on operating parameters 
of the metal emission control device to ensure that collection 
efficiency is maintained. It is also difficult to ensure that the other 
major factors that can affect metals emissions are adequately addressed 
by operating limits. For example, factors that affect metal volatility 
and subsequently metals emissions may include chlorine feedrates, 
combustion chamber temperature, and temperature at the inlet of the 
emission control device. Finally, the common process of spiking metals 
during compliance testing to ensure an adequate operating envelope is 
expensive, potentially dangerous to the testing crew that must handle 
the toxic metals, and causes higher than normal emission rates during 
compliance testing. If a MM CEMS were available, there would not be a 
need to spike metals during compliance testing.
---------------------------------------------------------------------------

    \149\ We note that several cement and light-weight aggregate 
kilns have been fined because of inadequate feedstream analysis 
plans.
---------------------------------------------------------------------------

    i. How to Address Metals that a CEMS May Not Be Able to Measure. 
Several MM CEMS are currently under development, and not all of them 
will be able to measure all metals in the SVM (Pb and Cd) and LVM (As, 
Be, Cr, and Sb) groupings. Clearly, a MM CEMS cannot be used to 
document compliance for a metal it cannot measure. For metals a MM CEMS 
cannot measure, it is proposed that facilities assume that all of that 
metal fed is emitted at the stack and that this metal feedrate be used 
in calculating the emissions for the metal group. Alternately, EPA 
could decide that a MM CEMS which does not measure all the metals could 
not be used as CEMS for compliance with the SVM and LVM standards. EPA 
invites comment on this issue.
    For example, x-ray fluorescence analyzers do not measure Be. If a 
facility chooses to use a MM CEMS which employs an x-ray fluorescence 
analyzer, it would take the MM CEMS results for As, Cr, and Sb, and the 
mass feedrate for Be (corrected to effluent concentrations by dividing 
by the average gas flowrate) and sum the four together. This would 
constitute the LVM emissions for the averaging period that would be 
used to determine compliance.
    ii. Performance Specifications for a MM CEMS. The performance 
specification for a MM CEMS is proposed here as Part 60, Appendix B, 
Performance Specification (PS) 10. Lacking a commercially available MM 
CEMS to test prior to developing the performance specification created 
unique challenges to developing a MM CEMS PS. The Agency's approach to 
developing the PS was to base performance criteria as much as possible 
on existing performance specifications. The Agency also worked closely 
with MM CEMS developers, through the American Society of Mechanical 
Engineers, to ensure that the MM CEMS PS would be representative of the 
performance of commercially available devices. EPA specifically invites 
comment on the performance specification.
    It is also proposed that special quality assurance (QA) 
requirements also pertain to MM CEMS. (See subsection F.1. of this 
section for more information on CEMS QA requirements.) We propose that 
the owner/operator perform a relative accuracy test audit (RATA) on the 
MM CEMS at least once every three years (five years for small on-site 
facilities). The RATA compares the output of the MM CEMS to the 
reference method. For the purposes of these source categories, the 
reference method for stack metals determinations is the current BIF 
Method 0012 (SW-846 Method 0060). The QA requirements also propose that 
an absolute calibration audit (ACA) be conducted in years the RATA is 
not

[[Page 17430]]

conducted. The ACA would involve making nine measurements using an NIST 
traceable calibration standard at three levels for each metal the CEMS 
measures. NIST traceable solutions of metals are currently available 
which challenge the analyzer device only. EPA is currently developing 
the NIST traceable metal standard which will challenge the entire 
system, not just the analyzer.
    c. Option 2: Use of Limits on Operating Parameters to Document 
Compliance. If a source elects not to use a MM CEMS (or a CEMS is not 
commercially available), the rule would require the source to establish 
a site-specific PM limit and comply with limits on metals feedrate, 
chlorine feedrate, and maximum temperature at the inlet to the PM 
control device. These limits would be established during the 
comprehensive performance test when the source demonstrates compliance 
with the emission limits by manual stack sampling.
    i. PM Limit. SVM and LVM (and adsorbed D/F) are controlled by the 
PM control device. To ensure that the collection efficiency of the PM 
device is maintained after the comprehensive performance test, EPA is 
proposing to require that a PM limit be established as the lower of the 
level occurring during the SVM, LVM, and D/F performance testing or the 
MACT standard. For PM monitoring requirements see section 7, below.
    ii. Maximum Inlet Temperature to Dry PM APCDs. High inlet 
temperatures to dry PM APCDs can cause low recovery of metals in the 
APCD because at higher temperatures a larger portion of some metals 
will be in the vapor phase. (Dry PM control devices do not control 
vapor phase metals.) This happens because metal volatility increases 
with increasing temperature. Therefore, EPA proposes that the inlet 
temperature to a dry PM APCD be maintained at a level no higher than 
that during the comprehensive performance test.
    The Agency proposes that maximum inlet temperature to a dry PM APCD 
be maintained on both a 10-minute and a one-hour average. The 10-minute 
average would be the average of the maximum inlet temperatures 
experienced during each compliance test run and the one-hour average 
would be the average over all runs.
    iii. Maximum SVM and LVM Feedrate Limits. Given the correlation 
between feedrate and emission rate, the rule would limit feedrate of 
SVM and LVM to levels fed during the comprehensive performance test. 
For LVM, feedrate limits would be set on both pumpable liquids and 
total feedstreams separately. A separate limit is proposed for pumpable 
feedstreams because metals present in pumpable feedstreams may 
partition between the combustion gas and bottom ash (or kiln product) 
at a higher rate than metals in nonpumpable feedstreams.
    For SVM, the feedrate limit would apply to all feedstreams. 
Separate limits would not be established for pumpable versus total 
feedstreams. This is because partitioning between the combustion gas 
and bottom ash or product does not appear to be affected by the 
physical state of the feedstream. 150
---------------------------------------------------------------------------

    \150\ See USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume IV: Compliance with the Proposed MACT Standards'', 
February 1996.
---------------------------------------------------------------------------

    Sources would be required to perform sampling and analysis of all 
feedstreams (including hazardous waste, raw materials, and other fuels 
and additives) for SVM and LVM content to document compliance with the 
feedrate limits. See also the discussion in section II.F.2. below for 
other requirements to document compliance with feedrate limits.
    The rule would base the feedrate limit for SVM and LVM on a twelve-
hour average basis. The limit would be established as twelve times the 
average hourly feedrate during the comprehensive performance test. 
Also, facilities would be required to record not only the total feed at 
each individual feed location for SVM and LVM, but the total sum of the 
SVM feed and the LVM feed at the various locations.
    As mentioned above in Subsection B, this twelve-hour average is 
inconsistent with the ten-hour averaging period for metals CEMS. CEMS 
should have longer averaging periods than operating parameters such as 
feedrates. Therefore, EPA invites comment on whether the averaging 
period for all SVM and LVM feedrates should be promulgated at six, 
instead of 12, hours. EPA believes a six-hour averaging period for all 
SVM and LVM feedrates is sufficiently conservative, relative to the 
CEMS averaging period and achievable.
    The grouping of metals by volatility means that it is possible for 
one metal within the volatility group to be used during performance 
testing as a surrogate for other metals in that volatility group. For 
instance, As may be used as a surrogate during the comprehensive 
performance test for all LVMs. Similarly, lead could be used as a 
surrogate for Cd, the other SVM. In addition, either SVM could be used 
as a surrogate for any LVM. This will help alleviate concerns 
facilities have voiced regarding the need to spike each metal during 
BIF certification of compliance testing. Facilities would not need to 
spike each metal to comply with today's rule, but only one metal within 
the group (or potentially one SVM for both categories).
    iv. Maximum Chlorine Feedrate. The rule would establish a maximum 
feedrate for total chlorine and chloride based on the level fed during 
the comprehensive performance test. A limit on maximum chlorine feed is 
necessary because most metals are more volatile in the chlorinated 
form. Although most of the volatilized SVM and LVM will condense to 
particulate form before entering the PM control device, the metals 
condense in a fine particulate fume that is more difficult for most PM 
control devices to collect than larger particulate.
    The rule would require sampling and analysis of each feedstream for 
total chlorine and chloride to document compliance with the feedrate 
limit for total feedstreams. The maximum feedrate would be based on a 
twelve-hour average, and would be established as twelve times the 
hourly average feedrate during the comprehensive performance test. Note 
also the requirements for documenting compliance with feedrate limits 
discussed in section II.F.2.
    Again, this twelve-hour average is inconsistent with the one-hour 
averaging period for HCl and Cl2 CEMS. CEMS should have longer 
averaging periods than operating parameters such as feedrates. 
Therefore, EPA invites comment on whether the averaging period for 
chlorine feedrate should be promulgated at one, instead of 12, hours. 
EPA believes a twelve-hour averaging period for chlorine feedrate is 
not be sufficiently conservative, relative to the one-hour CEMS 
averaging period. However, EPA also believes that a shorter averaging 
period for feedrates may be difficult for some facilities, particularly 
those with diverse feedstreams, to achieve routinely. For this reason, 
the twelve-hour average is proposed and comment is sought on the one 
hour-average.
    We note that if a facility uses a CEMS for compliance with the Hg, 
SVM, LVM, and HCl and Cl2 standards, there would be no need for 
the facility to establish a total chlorine and chloride feedrate limit.
    v. Special Requirements for Cement and Lightweight Aggregate Kilns 
that Recycle Collected Particulate Matter. Cement kilns and lightweight 
aggregate kilns that recycle collected particulate matter (which is 
primarily raw material that is entrained in kiln gas) pose a

[[Page 17431]]

special problem to ensure compliance with metals emission standards. 
These sources (particularly cement kilns) feed a variety of feedstocks 
which makes feedstream analysis problematic. Also, when these sources 
spike metals in feedstreams for purposes of performance testing, it may 
take several hours or days to reach steady-state emissions.
    Under the BIF rule, these sources must comply with one of three 
requirements: (1) Daily monitoring of collected PM to ensure that 
metals levels do not exceed limits that relate concentration of the 
metal in the collected PM to emitted PM; (2) daily stack sampling for 
metals; or (3) conditioning of the furnace system prior to performance 
testing to ensure that metals emissions are at equilibrium with metals 
feedrates. See 56 FR 7176-78 (February 21, 1991), existing 
Sec. 266.103(c)(6), and proposed Sec. 63.1210(n). We propose to 
continue to require that these sources comply with one of the three BIF 
alternative approaches for compliance with the MACT metals standards.
    We understand, however, that the approach of daily monitoring 
collected PM to document compliance with the BIF metal standards (see 
Section 10 of Appendix IX to Part 266, ``Alternative Methodology for 
Implementing Metals Controls'') is not currently being used by any 
facility because it is too complicated and burdensome. (The methodology 
involves empirically relating the concentration of each metal in the 
emitted PM to the concentration of the metal in collected PM (i.e., the 
enrichment factor).) The Cement Kiln Recycling Coalition (CKRC) has 
suggested several revisions to the methodology 151 including: (1) 
Reduced testing frequency to establish and periodically confirm the 
enrichment factor; (2) assuming PM emissions 152 are at normal 
levels rather than maximum allowable levels; (3) a less conservative 
approach to estimate the enrichment factor for nondetect metals in 
collected PM (based on new sampling and analysis techniques and 
improved understanding of metals behavior); and (4) allowing all kilns 
to comply with a revised methodology, not just kilns that recycle 
collected PM. (The Agency believes the approach may, in fact, be 
appropriate for any HWC and invites comment on this matter.) In 
addition, CKRC raises several questions regarding the statistical 
foundations of the methodology.
---------------------------------------------------------------------------

    \151\ See letter from Craig Campbell, CKRC, to James Berlow, 
EPA, undated but received on February 20, 1996.
    \152\ Note that PM emissions from CKs are comprised primarily of 
raw material entrained in the kiln off-gas. The material is known as 
cement kiln dust (CKD).
---------------------------------------------------------------------------

    The Agency invites comment on CKRC's recommendations to improve the 
collected PM monitoring methodology and on other approaches to make the 
methodology a more workable but effective compliance approach in lieu 
of monitoring feedrates of metals in feedstreams.
5. Carbon Monoxide (CO), Hydrocarbons (HC), and Oxygen (O2)
    EPA is proposing that facilities demonstrate compliance with the CO 
and HC standards by using CEMS. See proposed Sec. 63.1210(p) and (q). 
EPA is not proposing a standard for O\2\,153 but all of the 
standards are based on correction to 7 percent O\2\. Therefore, EPA 
proposes facilities monitor O2 by using a CEMS. Many HWCs are 
already equipped with these monitors to comply with the existing 
incinerator or BIF regulations.
---------------------------------------------------------------------------

    \153\ Except that batch-fired HWCs would be required to comply 
with a minimum combustion chamber oxygen level prior to feeding a 
batch to maintain compliance with the D/F standard.
---------------------------------------------------------------------------

    EPA proposes performance specifications for CO and O2 CEMS in 
Performance Specification 4B of Appendix B, Part 60. EPA proposes a 
total hydrocarbon (THC) CEMS performance specifications based on the 
use of a heated flame ionization detector (i.e., heated FID). The HC PS 
will be Performance Specification 8A contained in Appendix B, Part 60. 
Both PSs are similar to those currently used for BIFs. The minor 
proposed changes are discussed below.
    a. Averaging Period for CO and HC CEMS. The averaging period for CO 
and HC CEMS is proposed to be a one-hour rolling average. This is 
because this a one-hour rolling average is the same averaging period 
currently used in the BIF rule. Changing the averaging period would 
necessitate changing the emission standard (see Part Four, Section II) 
to maintain the same stringency for the different averaging period. EPA 
does not believe this is warranted, so the one-hour rolling average is 
proposed.
    b. CO and HC CEMS Performance Specifications. Performance 
specifications for CO and O2 CEMS are proposed here as Performance 
Specification 4B. This performance specification is essentially the 
same as the specification for BIFs provided in Appendix IX of Part 266. 
This performance specification is the very similar to existing Appendix 
B Performance Specifications 3 (for O2) and 4A (for CO). It 
references many of the provisions of the two other specifications. What 
the proposed specification does do is describe how the current BIF CEMS 
performance specifications differ from performance specifications 3 and 
4A and prescribes the BIF specifications in instances when differences 
occur. EPA is proposing specification 4B because it believes it is 
important to ``grandfather'' in the current performance specifications 
for administrative and cost reasons. Performance specification 4B does 
not differ substantially from the current Part 60 specifications. 
Therefore, EPA invites comment on whether to not propose performance 
specification 4B and instead rely on the existing specifications 3 and 
4A.
    Also, performance specifications 3 and 4A (which performance 
specification 4B refers to) requires a Relative Accuracy Test Audit 
(RATA) be performed on the CEMS. It also allows for a waiver of the 
RATA requirement if an acceptable substitute is used. The Agency is 
currently moving away from requiring RATAs for CEMS for which cylinder 
gases are available. Cylinder gases are available for both CO and O\2\, 
so we invite comment on whether the RATA requirements not be included 
in performance specification 4B. EPA would still require facilities to 
perform quarterly absolute calibration audits (ACAs) using calibration 
error (CE) test procedures for these CEMS. EPA invites comment on 
whether the RATA requirement should not be promulgated and whether just 
a quarterly ACA is adequate without a RATA.
    HC CEMS performance specifications are proposed here as Performance 
Specification 8A. It is identical to the performance specification 
contained in section 2.2 of Appendix IX of Part 266, except the quality 
assurance section has been deleted and placed in the appendix to 
Subpart EEE, Part 63, to be consistent with the Agency's approach to 
Part 60 performance specifications.
    There is an existing performance specification, number 8, for a 
volatile organic compound (VOC) CEMS. Performance specification 8 does 
not rely on heated sampling lines and detector. A cold VOC monitor does 
not measure less volatile hydrocarbons which, due to heating, are 
measured by a heated FID but not a cold VOC monitor. (Heavy 
hydrocarbons would condense out in the sampling line and in the 
analyzer in a VOC CEMS and not be measured as hydrocarbon emissions. 
Therefore, a VOC CEMS measures a subset of what a heated FID measures.) 
Using the VOC performance specification would be problematic because 
the emission standard was

[[Page 17432]]

established using the results from heated FIDs, not cold VOC CEMS. EPA 
believes allowing compliance with a CEMS that measures only a subset of 
the pollutants represented by the standard is inappropriate. For this 
reason, we decided against proposing the use of performance 
specification 8. EPA believes it is appropriate to propose performance 
specification 8A to ``grandfather'' in the current specifications and 
keep compliance monitoring in agreement with how the standard was 
derived.
    One issue that has arisen during the implementation of the BIF rule 
is that the stated span values for the CO CEMS may lead to high error 
in the facility's calculated emission value. For instance, a CK may 
analyze for CO emissions in the bypass duct, and analyses in bypass 
ducts can have very high oxygen correction factors, on the order of 10. 
At the low range CO span of 200 ppm with an acceptable calibration 
drift of 3 percent, or 6 ppm, this means that error in the standard due 
to calibration drift would be 60 ppm if the oxygen correction factor is 
ten. An absolute calibration drift of 60 ppm is more than half the CO 
standard of 100 ppm and many believe this is unacceptable.
    Therefore, EPA wishes to clarify the ranges for CEMS, stating that 
the spans for low and high ranges are expressed at an oxygen correction 
factor of 1. Facilities which normally operate at oxygen correction 
factors more than 2 would have to use CEMS with spans proportionately 
lower than the stated values, relative to the oxygen correction factor 
at the sampling point.
    In the example above, where the oxygen correction factor is 10, the 
suggested value of the low range span for the CO CEMS would be 200 
divided by 10, or 20 ppm. If the low CO range is 20, the oxygen 
correction factor is 10, and the calibration drift is 3 percent of the 
span of the range, then the absolute calibration drift would be 6 ppm.
    Because the span value is a suggested value, the facility could use 
a 25 ppm span value to satisfy this requirement. This modification is 
contained in the CEMS Quality Assurance section of the proposed rules 
and would apply to the other CEMS except the oxygen CEMS, where the 
oxygen correction factor does not apply. It is proposed that 
corresponding changes be made to the BIF rule as well.
    An issue which also relates to the oxygen correction factor is that 
it grows exponentially as oxygen levels increase, particularly at 
oxygen concentrations above 15 to 17 percent. Some facilities 
experience high oxygen correction factors at times of start-up or shut-
down because combustion has just commenced or is just completing and, 
as a result, there is very high levels of excess oxygen in the 
combustor. For this reason, EPA invites comment on whether it would be 
appropriate to cap the oxygen correction factor at some multiplier 
above the facility's normal operating correction factor for a specified 
period of time, on the order of minutes, after a start-up or prior to a 
shut-down.
6. Hydrochloric Acid (HCl) and Chlorine Gas (Cl2)
    Table V.2.5 summarizes the proposed HCl/Cl2 compliance 
monitoring requirements and other options being considered. See also 
proposed Sec. 63.1210(o).

                          Table V.2.5.--Proposed HCl/Cl2 Compliance Monitoring Requirements and Other Options Being Considered                          
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                    Operating limit avg 
                                                                Compliance using          Limits from             Avg period              pd basis      
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed Option 1 (Facility Choice)  Max Flue Gas Flowrate   Same..................  Comp Test............  1 hour...............  Avg of Max 1 hour    
                                      or Production Rate.                                                                           RAs.                
                                     Max Chlorine Feedrate.  Feedstream Analysis...  Comp Test............  12 hour..............  Avg over all runs.   
                                     Min Press Drop, Wet     Press drop across       Comp Test............  10 min...............  Avg of Min 10 min    
                                      Scrubber.               scrubber.                                                             RAs.                
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Liq Feed Pressure,  Pressure..............  Manuf Spec...........  10 min...............                       
                                      Wet Scrubber.                                                                                                     
                                     Min Liq pH, Wet         pH....................  Comp Test............  10 min...............  Avg Min 10 min RAs.  
                                      Scrubber.                                                                                                         
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Liq/Gas Ratio, Wet  Scrubber liquid and     Comp Test............  10 min...............  Avg Min 10 min RAs.  
                                      Scrubber.               gas flowrates.                                                                            
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Sorbent Feedrate,   Sorbent Feedrate......  Comp Test............  10 min...............  Avg of Min 10 min    
                                      Dry Scrubber.                                                                                 RAs.                
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Carrier Fluid       Carrier fluid flowrate  Manuf Spec...........  10 min...............                       
                                      Flowrate or Nozzle      or pressure drop.                                                                         
                                      Pressure Drop, Dry                                                                                                
                                      Scrubber.                                                                                                         
                                     Sorbent Specs, Dry      Brand and Type........  Comp Test............  N/A..................  Same brand and type. 
                                      Scrubber.                                                                                                         
Proposed Option 2 (Facility Choice)  CEMS..................  HCl and Cl2 CEMS......  CEMS Std.............  2 hours..............                       
Additional Option..................  Surrogate CEMS........  HCl CEMS..............  Comp Test............  2 hours..............  Avg over all runs.   
                                     Factors Affecting Cl2   TBD...................  Comp Test............  TBD..................  TBD.                 
                                      Formation.                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------

    a. Evaluation of Monitoring Options. The rule would allow sources 
the option of using separate CEMS to monitor HCl and Cl\2\ emissions or 
to comply with limits on operating parameters.
    HCl CEMS are commercially available and have been used at permitted 
municipal waste combustor sources and

[[Page 17433]]

some HWCs for many years. Cl2 CEMS are currently being marketed by 
a European manufacturer. Although the Agency prefers the use of CEMS 
whenever they are available for compliance monitoring, we are concerned 
that the use of CEMS to monitor HCl and Cl2 emissions may not be 
cost-effective. This is because facilities are likely to be required to 
monitor chlorine feed to demonstrate compliance with the SVM and LVM 
standards anyway, given that a multi-metal CEMS may not be commercially 
available for some time.154 Accordingly, the rule would allow, but 
not require, the use of CEMS for HCl and Cl2.
---------------------------------------------------------------------------

    \154\ If we determine that multi-metal CEMS are commercially 
available at promulgation and require their use in the final rule, 
we may also require the use of CEMS to monitor HCl and Cl2 
emissions.
---------------------------------------------------------------------------

    We note that we considered the feasibility of allowing the use of 
an HCl CEMS only, whereby the HCl CEMS would be used as a surrogate for 
the HCl/Cl\2\ standard. As discussed below, we determined, however, 
that this approach would be more complicated, more costly, have 
technical problems, and/or provide less assurance of compliance. We 
nonetheless invite comment on whether the use of an HCl CEMS as a 
compliance parameter for the HCl and Cl2 standard could be a 
workable approach.
    b. Compliance Using Limits on Operating Parameters. If a source 
elects not to use separate HCl and Cl2 CEMS to demonstrate 
compliance with the HCl/Cl2 standard, the rule would require the 
source to establish limits on the following operating parameters based 
on operations during the comprehensive performance test to ensure it 
maintains compliance with the standard: maximum feedrate of total 
chlorine and chloride from all feedstreams, and limits on the acid gas 
APCD operating parameters discussed below.
    i. Maximum Flue Gas Flowrate or Production Rate. If flue gas 
flowrates exceed those during the comprehensive performance test, the 
HCl/Cl2 collection efficiency of the control device may not be 
maintained which may result in emissions that exceed the standard. 
Therefore, EPA proposes that maximum flue gas flowrate be controlled to 
levels that are no higher than those during the performance test. 
Alternatively, CKs and LWAKs may establish a maximum production rate 
(e.g., raw material feedrate or clinker or aggregate production rate) 
in lieu of a maximum gas flowrate given that production rate directly 
relates to flue gas flowrate. The limit would be based on a one-hour 
average and be established as the average of the maximum hourly rolling 
average for each run of the comprehensive performance test.
    ii. Maximum Total Chlorine or Chloride Feedrate. The rule would 
limit the amount of total chlorine or chloride fed in all feedstreams 
to levels that were fed during the comprehensive performance test 
demonstrating compliance with the HCl/Cl2 standard. Sources would 
be required to perform sampling and analysis of each feedstream for 
total chlorine and chloride content to document compliance with the 
feedrate limit for total feedstreams. See also the discussion in 
section II.F.2 for other requirements to document compliance with 
feedstream limits.
    The total chlorine and chloride feedrate limit would be averaged 
over a twelve-hour period and would be established as twelve times the 
hourly feedrate during the comprehensive performance test.
    We again note that there is an inconsistency between this twelve-
hour feedrate average and the proposed one-hour averaging period for 
HCl and Cl2 CEMS. EPA invites comment on whether the averaging 
period for chlorine feed should be promulgated at one, instead of 
twelve, hours.
    Note that if a facility uses a CEMS for compliance with the HCl and 
Cl2, Hg, SVM, and LVM standards, no chlorine feed monitoring would 
be required.
    iii. Wet Scrubber Parameters. Wet scrubbers can be used to control 
HCl and Cl2 emissions. To ensure that the control efficiency of a 
wet scrubber is maintained at levels achieved during the comprehensive 
performance test, the rule would require sources to establish limits on 
the following operating parameters: pressure drop across the scrubber; 
liquid feed pressure; liquid (blowdown) pH; and liquid to gas flow 
ratio.
    Pressure drop across a wet scrubber is an important parameter 
because it is an indicator of good mixing of the two fluids, the 
scrubber liquid and the flue gas. A low pressure drop would indicate 
poor mixing and, hence, poor efficiency. A high pressure drop would 
indicate good removal efficiency. Therefore, EPA proposes that the 
pressure drop across the scrubber be limited to the minimum level 
during the comprehensive performance test. Limits would be based on 
both a ten-minute and a one-hour average. The ten-minute average limit 
would be established as the average of the lowest ten-minute rolling 
average for each run, and the hourly average limit would be established 
as the average over all runs.
    Scrubber liquid feed pressure is important because it directly 
relates to the amount of scrubber liquid pumped into the scrubber and 
is easier to measure than scrubber liquid flow directly. The more 
scrubber liquid pumped into the scrubber, the better the removal 
efficiency. If liquid flow were to decrease, the removal efficiency 
would also decrease. EPA proposes that minimum liquid feed pressure be 
maintained on a ten-minute average and that the limit be the minimum 
value established by the scrubber manufacturer.
    The pH of the scrubber liquid is also important because, at low pH, 
the scrubber solution is more acidic and removal efficiency of HCl 
decreases. We propose that the pH be determined from the blowdown 
liquid. This is because it is the best indicator of scrubber efficiency 
by measuring pH of scrubber liquid. EPA proposes that minimum pH of the 
scrubber water be controlled on both a ten-minute and a one-hour 
average. The ten-minute average limit would be established as the 
average of the lowest ten-minute rolling average for each run, and the 
hourly average limit would be the average over all runs.
    EPA solicits comment on whether the alkaline reagent (such as lime) 
concentration in the scrubber should be a control parameter for 
alkaline wet-scrubbers. This parameter is closely related to the just 
mentioned pH since the concentration of alkaline reagent in the 
scrubber will keep the scrubber liquid pH high. EPA believes this 
parameter is important because the alkaline reagent is what removes 
Cl2 and, to a lesser extent, HCl from the flue gas. pH is a 
secondary indicator of this parameter. EPA's concern is alkaline 
reagent concentrations can be low enough to lower the efficiency of wet 
scrubbers yet buffer the scrubber liquid enough to maintain pH. 
However, the concentration of alkaline reagent in the scrubber liquid 
can not be continuously monitored as easily as pH. We invite comment on 
whether the concentration of alkaline reagent in the scrubber liquid 
should be a control parameter for wet scrubbers, whether this parameter 
should be in addition to or in lieu of the pH parameter, and what 
averaging period(s) such a parameter should have.
    In addition, EPA invites comment on whether a ten-minute average is 
appropriate for pH (and/or alkaline reagent concentration). Some 
facilities may not automate their wet scrubbers to add scrubbing 
solutions as needed to maintain scrubber efficiency. Such facilities 
make up batches of virgin scrubber solution and add it to the scrubber 
liquid. In this case, it might be

[[Page 17434]]

more appropriate to establish a parameter ensuring that batches of new 
scrubber solution is added to the wet scrubber prior to the scrubber 
liquid pH (and/or possibly alkaline reagent) reaching a certain level.
    Liquid to gas flow ratio is another important wet scrubber 
parameter. A high liquid to gas flow ratio indicates good scrubber 
removal, while a low liquid to gas flow ratio indicates less efficient 
removal. EPA proposes that the minimum scrubber liquid to flue gas flow 
ratio be controlled on both a ten-minute and a one-hour average. The 
ten-minute average limit would be established as the average of the 
lowest ten-minute rolling average for each run, and the hourly average 
limit would be established as the average over all runs.
    iv. Dry Scrubber Parameters. A dry scrubber removes HCl from the 
flue gas by adsorbing the HCl onto some sorbent, normally an alkaline 
substance like limestone. To ensure that the collection efficiency of 
the scrubber is maintained at comprehensive performance test levels, 
the rule would require sources to establish limits on the following 
operating parameters: sorbent feedrate; carrier fluid flowrate or 
nozzle pressure drop; and sorbent specifications.
    Sorbent feedrate is important because, when more sorbent is fed 
into the dry scrubber, removal efficiency for HCl and Cl2 will 
increase.155 Conversely, lower sorbent feedrates tend to cause 
removal efficiency to decrease. Therefore, EPA proposes that the 
minimum sorbent feedrate into the dry scrubber be controlled on both a 
ten-minute and a one-hour rolling average. The ten-minute average limit 
would be established as the average of the lowest ten-minute rolling 
average for each run, and the hourly average limit would be established 
as the average over all runs.
---------------------------------------------------------------------------

    \155\ EPA notes that sorbent to a dry scrubber should be fed in 
excess of the stoichiometric requirements for neutralizing the anion 
component in the flue gas. Lower concentration of sorbent, even 
above stoichiometric requirements, would limit the removal of acid 
gasses.
---------------------------------------------------------------------------

    Carrier fluid is some liquid or gas (normally air or water) which 
transports the sorbent into the dry scrubber. Without proper carrier 
flow to the dry scrubber the sorbent flow into the dry scrubber will 
decrease, and efficiency will also decrease. Nozzle pressure drop is 
also an indicator of carrier gas flow into the scrubber. At a 
relatively high pressure drop, more sorbent is carried to the dry 
scrubber. At lower pressure drop, less sorbent is carried to the 
scrubber. Therefore, the rule would require that carrier fluid flowrate 
or nozzle pressure drop be maintained to the minimum levels occurring 
during the comprehensive performance test. Limits would be established 
on both a ten-minute and a one-hour rolling average. The ten-minute 
average limit would be established as the average of the lowest ten-
minute rolling average for each run, and the hourly average limit would 
be established as the average over all runs.
    As was the case with maintaining the quality of carbon used in 
carbon injection and carbon bed systems for control of D/F and Hg, the 
rule would require that the quality of sorbent be maintained after the 
comprehensive performance test. Therefore, the rule would require 
sources to continue to use the same sorbent brand and type as they used 
during the comprehensive performance test. The rule would allow a 
source to obtain a waiver from this requirement from the Director, 
however, if the owner or operator: (1) documents by data or information 
key characteristics of the sorbent which controls HCl and Cl2; (2) 
documents by data or information specification levels corresponding to 
those characteristics; and (3) complies with the specification.
    As was the case for pH in wet scrubbers, EPA invites comment on 
whether a ten-minute average is appropriate for sorbent feedrate. Some 
facilities may not automate their dry scrubbers to add sorbent 
solutions as needed to maintain scrubber efficiency. Such facilities 
make up batches of virgin sorbent solution and add it to a dry scrubber 
feed tank containing the sorbent. In this case, it might be more 
appropriate to establish a parameter ensuring that batches of new 
scrubber sorbent is added to the dry scrubber prior to the sorbent 
concentration in the dry scrubber reaching a certain level.
    c. Compliance Using Separate HCl and Cl2 CEMS. The rule would 
allow sources to use separate HCl and Cl2 CEMS to demonstrate 
compliance with the HCl/Cl2 standard. This option would allow for 
the direct measurement of the standard, at the top of the monitoring 
hierarchy, but does so at a higher cost relative to the previous option 
of compliance with limits on operating parameters. EPA seeks comment on 
whether the use of separate HCl and Cl2 CEMS is in fact cost-
effective and should be required in the final rule in lieu of allowing 
compliance with operating limits.
    Under this option, compliance would be demonstrated by measuring 
HCl emissions (in ppmv) with the HCl CEMS and measuring Cl2 
emissions (in ppmv) with a Cl2 monitor. Since the HCl and Cl2 
standard is based on equivalents of HCl, the ppmv emissions of Cl2 
must be multiplied by two and added to the HCl emissions to determine 
the combined emission level. If this result is lower than the emission 
standard, then the facility is in compliance with the HCl/Cl2 
standard.
    i. HCl CEMS. HCl CEMS are proven technologies, available worldwide, 
and are currently required in the permits of many MWCs. Several HWCs 
also use HCl CEMS. HCl CEMS are not expensive; the purchase cost are 
$12,000 to $55,000.156
---------------------------------------------------------------------------

    \156\ See Chapter 2.6 of USEPA, ``Draft Technical Support 
Document for HWC MACT Standards, Volume IV: Compliance with the 
Proposed MACT Standards'', February 1996.
---------------------------------------------------------------------------

    Performance specifications for a HCl CEMS are proposed today as 
Performance Specification 13 of Appendix B, Part 60. The proposed 
appendix to Part 63, Subpart EEE, also proposes certain RATA and ACA 
requirements.
    ii. Cl2 CEMS. Cl2-specific CEMS are currently being 
marketed by Opsis, a European CEMS manufacturer. These devices have 
been certified for use in Germany and can also be used to monitor for 
HCl, CO, NOX, SOX, and NH3. This device would likely be 
a cost-effective option for new facilities or existing facilities 
purchasing a suite of new CEMS.
    Performance specifications for Cl2 analyzers are proposed here 
as Performance Specification 14 of Part 60, Appendix B. The proposed 
appendix to Part 63, Subpart EEE, also proposes certain RATA and ACA 
requirements.
    d. Consideration of Using an HCl CEMS Only. EPA requests comment on 
whether the use solely of an HCl monitor for compliance with the HCl/
Cl2 standard could be workable. If so, this approach could be 
allowed as an option in the final rule.
    This approach would provide direct monitoring of the HCl portion of 
the standard and act as a surrogate monitor for the Cl2 portion. 
However, EPA is concerned that poor correlation between HCl and 
Cl2 emissions may result in HCl being a poor surrogate for 
Cl2. For an HCl CEMS alone to be a feasible surrogate monitor for 
the HCl/Cl2 standard, this and other issues discussed below must 
be addressed.
    Cl2 and HCl form a post-combustion equilibrium. At 
temperatures above 1000 deg.F the equilibrium is quite stable and 
correlation is good. At lower temperatures, though, formation of 
Cl2 is favored over HCl and the equilibrium no longer holds. All 
HWCs experience temperatures lower than 1000 deg.F, so the HCl/Cl2 
equilibrium does not hold. The formation of Cl2 under these 
circumstances is dependent on a

[[Page 17435]]

number of site-specific conditions, such as the post-combustion 
temperature profile and hence the rate of conversion to Cl2, and 
residence time from the point where Cl2 formation is favored to 
the stack. In fact, these conditions may vary at any given facility 
depending on the circumstances at any time after combustion. Given that 
HCl appears to be a poor indicator of Cl2 emissions, direct 
measurement of Cl2 is desired.
    If this issue can be adequately addressed, the use of only a HCl 
CEMS to demonstrate compliance with the standard would involve 
determining a site-specific HCl limit representative of the combined 
HCl/Cl2 emissions. This would involve a comprehensive performance 
test at maximum chlorine feed and under conditions which are worst-case 
for Cl2 formation and emissions and optimal for HCl removal. The 
resulting HCl level would become the site-specific limit to demonstrate 
compliance with the HCl/Cl2 standard.
    Limits on operating conditions would also be necessary to ensure 
that the ratio of Cl2 to HCl emissions is not higher than 
experienced during the comprehensive performance test, and that HCl 
control equipment is not operated more efficiently (note emphasis) 
after the performance test. Otherwise, the HCl emissions during normal 
operations may under-predict combined HCl and Cl2 emissions.
7. Particulate Matter (PM)
    As discussed above in the sections on operating limits for 
compliance with the D/F, SVM, and LVM standards, a PM limit would be 
established as the lower of either the levels that occurred during the 
comprehensive performance test to demonstrate compliance with the D/F, 
SVM, and LVM emission standards (as a compliance parameter for those 
standards) or the national PM standard. Table V.2.6 below summarizes 
the proposed monitoring requirements and options being considered.

                                  Table V.2.6.-- Proposed PM Monitoring Requirements and Other Options Being Considered                                 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                    Operating limit avg.
                                                                Compliance using          Limits from            Avg. period              pd basis      
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed Requirement...............  CEMS..................  PM CEMS...............  CEMS Std.............  2 hours..............                       
                                                                                     D/F or SVM/LVM Comp    10 Min...............  Lowest Avg Min 10 min
                                                                                      Test.                                         RAs.                
                                                                                                            1 hour...............  Lowest Avg over all  
                                                                                                                                    runs.               
Option: Feedstream and Operating     Max Flue Gas Flowrate   Same..................  Comp Test............  1 hour...............  Avg of Max 1 hour    
 Parameter Limits.                    or Production Rate.                                                                           RAs.                
                                     Max Ash Feedrate......  Feedstream Analysis...  Comp Test............  12 hour..............  Avg over all runs.   
                                     Min Press Drop, Wet     Press drop across       Comp Test............  10 min...............  Avg of Min 10 min    
                                      Scrubber including      scrubber.                                                             RAs.                
                                      Ionizing Wet Scrubber.                                                                                            
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Scrubber Feed       Pressure..............  Manuf Specs..........  10 min...............  N/A.                 
                                      Press, Wet Scrubber                                                                                               
                                      including Ionizing                                                                                                
                                      Wet Scrubber.                                                                                                     
                                     Min Blowdown or Max     Liquid Flowrate or      Comp Test............  10 min...............  Avg of Min/Max 10 min
                                      Solid Content in Liq,   Solid Content.                                                        RAs.                
                                      Wet Scrubber                                                                                                      
                                      including Ionizing                                                                                                
                                      Wet Scrubber.                                                                                                     
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Liq/Gas Ratio, Wet  Scrubber Liquid and     Comp Test............  10 min...............  Avg Min 10 min RAs.  
                                      Scrubber including      Gas Flowrates.                                                                            
                                      Ionizing Wet Scrubber.                                                                                            
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Pressure Drop,      Pressure Drop Across    Comp Test............  10 min...............  Avg Min 10 min RAs.  
                                      Fabric Filter.          Fabric Filter.                                                                            
                                                                                                            1 hour...............  Avg over all runs.   
                                     Min Power Input.......  Voltage...............  Comp.................  10 min...............  Avg Min 10.          
                                                                                                            1 hour...............  Avg over all runs.   
--------------------------------------------------------------------------------------------------------------------------------------------------------

    a. Evaluation of Monitoring Options. Continuous PM CEMS are 
commercially available and installed on stacks worldwide. EPA proposes 
that facilities maintain continuous compliance with the PM standard 
through the use of a PM CEMS. PM CEMS are installed for compliance 
purposes in the European Union (EU) with the EU hazardous waste 
combustor PM standard of 13 mg/dscm. Germany has been in the forefront 
in the development, certification, and application of PM CEMS.
    i. Evaluation of PM CEMS feasibility and use. EPA in the past has 
relied on opacity monitors to indicate compliance with a PM standard. 
Opacity CEMS used in accordance with performance specification 1 have 
been a valid tool to indicate PM APCD failures and the necessity for 
corrective action as a result. However, opacity monitors are not, 
relatively speaking, very sensitive. They are typically useful down to 
about 45 mg/dscm. Today's proposed regulation will limit PM emissions 
to 69 mg/dscm. Opacity monitors would not be sufficient because to 
maintain compliance with 69 mg/dscm, facilities would generally need to 
operate around 35 mg/dscm. Thus, emissions will typically be below the 
detection limit of opacity monitors most of the time. While normal 
emission levels below the detection limits of CEMS are acceptable, 
facilities often desire the detection limit to be below one-tenth of 
the emission limit, or 7 mg/dscm for the proposed standard. This gives 
one sufficient

[[Page 17436]]

warning of how emissions are changing before the emission limit is 
approached, and allows the facility, based on CEMS readings, to change 
operations as necessary to be in compliance with the applicable 
standard. EPA has relied on opacity CEMS because there has not been 
available an acceptable quantitative monitor for continuous mass PM 
emissions. Opacity CEMS standards are established at a given percent 
opacity limit (generally 5-10 percent) over a 6-minute averaging period 
and, as stated, cannot distinguish particulate concentrations below 45 
mg/dscm. In other words, opacity CEMS as they are currently used can be 
used to ensure PM APCD efficiency but not to determine mass emissions 
in real time.
    If possible, EPA desires a quantitative, continuous measure of PM 
mass concentration rather than opacity. EPA has recently determined 
that CEMS do exist that do this: beta gauges and light scattering based 
CEMS. These CEMS rely on calibration of the device to manual 
gravimetric measurements. Therefore, EPA is proposing use of CEMS based 
on the availability of these newer technology PM CEMS and a related PM 
CEMS Performance Specification for monitoring PM mass concentration. 
This PS does not specify the type of CEMS used and allows the use of 
opacity monitors, which can also be calibrated to relate opacity to 
mass concentration. However, opacity is more sensitive to PM size 
distribution and physical properties, and has high detection 
limitations relative to the newer PM CEMS. As a result the calibration 
will be less stable for an opacity CEMS calibrated according to the 
proposed performance specification than one of the newer technology 
instruments.
    EPA believes that mass emission monitoring is feasible, and opacity 
monitoring has borderline sensitivity relative to today's proposed PM 
emission limit. The newer technology PM CEMS can give a real-time 
quantitative measure of PM mass emissions while opacity CEMS cannot. 
From a cost standpoint opacity monitoring is no less expensive than the 
alternative proposed here. As a result, EPA proposes to require mass 
emission monitoring rather than opacity monitoring.
    The German approach to using CEMS for PM compliance monitoring is 
based on the application of a practical engineering philosophy. PM CEMS 
are used despite the known sensitivities to various factors such as 
particle composition and size distribution since these devices are 
designed to minimize the impacts of these changes on the accurate 
measure of PM mass concentrations. The German experience on PM CEMS is 
that at controlled sources, i.e., those with low loading or equipped 
with PM control devices such as baghouses or ESPs, these sensitivities 
are not as important as they are at facilities with no control or high 
and/or highly varying grain loadings. The Germans have found that PM 
CEMS can be calibrated to manual methods to achieve a statistically 
reliable and enforceable calibration curve at controlled 
sources.157
---------------------------------------------------------------------------

    \157\ See Chapter 2.1 of USEPA, ``Draft Technical Support 
Document for HWC MACT Standards, Volume IV: Compliance with the 
Proposed MACT Standards'', February 1996.
---------------------------------------------------------------------------

    At periods when the particle composition and size changes 
dramatically, the PM CEMS calibration is not valid. However, this 
occurs when fuel is changed or the PM control device fails and causes 
very high grain loadings to occur. To account for the PM CEMS' 
sensitivity to fuel type, the Germans mandate a new calibration be made 
whenever the fuel is changed. During times of high grain loading the PM 
CEMS cannot accurately determine how high the PM emissions were. But at 
controlled devices, this only occurs when the PM control device fails 
and/or otherwise exceeds the PM standard. Therefore, PM CEMS remain a 
reliable indicator of compliance with a PM standard.
    In Germany, calibration of the PM CEMS defines a statistically 
derived site-specific calibration of the PM CEMS' response to various 
PM loadings. This is done by installing a plate in lieu of a bag in the 
baghouse or by varying the ESP voltage to allow various grain loadings 
to flow through the control device to the stack. The PM CEMS and manual 
methods are run simultaneously at various PM loadings to determine 
emissions. These PM CEMS outputs and manual methods results are used to 
statistically define the calibration curve for the PM CEMS.
    EPA has tested several of these devices at a hazardous waste 
incinerator and a cement kiln and has found that PM CEMS maintain 
calibration, even in a water saturated flue gas.
    ii. Types of PM CEMS available. The many types of PM CEMS fall into 
three broad categories: accumulated mass, impaction, and light 
scattering.
    For accumulated mass PM CEMS, stack gas is extracted isokinetically 
and particles are deposited on a sensing surface for mass measurement. 
Two types of accumulated mass devices are -radiation 
attenuators, commonly referred to as ``-gauge'' devices, and 
loaded oscillators. EPA has tested a stack-type -gauge but 
testing was inconclusive.158 EPA knows of no available stack-type 
loaded oscillator device.
---------------------------------------------------------------------------

    \158\ See Chapter 2.1 of USEPA, ``Draft Technical Support 
Document for HWC MACT Standards, Volume IV: Compliance with the 
Proposed MACT Standards'', February 1996.
---------------------------------------------------------------------------

    For impaction devices, particles impact upon a sensor surface due 
to the inertia imparted by the approaching gas stream. Two types of 
impaction PM CEMS are contact electrification, commonly referred to as 
``triboelectric'', and acoustic energy. Stack-type triboelectric 
devices are commercially available and in widespread use in France. 
However, EPA has concern about triboelectric PM CEMS since the physical 
property of PM which they work on, contact electrification, can vary 
the most from particle to particle even at controlled sources. For this 
reason, facilities should be aware that triboelectric PM CEMS may not 
be quantitative enough to be used for compliance with the PM standard. 
Acoustic energy PM CEMS are not in widespread use.
    Light scattering CEMS are preferred in Germany and are believed to 
be the PM CEMS most suitable for making measurements at low particulate 
levels typical of a well controlled source. Light scattering PM CEMS 
operate by sending a light beam across a path and measuring the light 
reflected back to a sensor at some angle from the source light. Several 
hundred of these devices have been certified for stack-use in the EU. 
EPA has also tested a time-dependant optical transmission device. Under 
certain circumstances, it can give results comparable to those of the 
light scattering device.
    To be in compliance with the PM limit, facilities would comply with 
the performance specifications and operating practices for the CEMS 
proposed here. If a PM CEMS is used at a facility, no feedstream or 
operating parameter limits will be necessary to document compliance 
with the PM limit. If a PM CEMS is not used, compliance with limits on 
feedstream and operating parameters will be necessary.
    iii. Control of PM Emissions. We are proposing to use a PM CEMS as 
a compliance parameter to ensure: (1) compliance with the national MACT 
PM standard; and (2) that the collection efficiency of the PM control 
device is maintained at performance test levels achieved when 
documenting compliance with the SVM, LVM, and D/F standards. Thus, it 
is necessary to

[[Page 17437]]

establish the PM limit as the lower of the level that occurs during the 
SVM, LVM, and D/F performance tests or the MACT standard. This is 
because a source could be operating well below the national PM standard 
during the performance test and, after the test, operate the PM control 
device at lower collection efficiency (e.g., to reduce operating costs, 
or because of reduced efficiency from ``wear and tear''). In this case, 
the source could continue to be in compliance with the national PM 
standard, yet exceed the D/F, LVM, and SVM emission limits because of 
increased emissions of adsorbed D/F, LVM, and SVM.
    To ensure that the collection efficiency is maintained while 
meeting the site-specific PM limit, the rule would require that 
feedstocks with normal levels of ash, i.e., those levels which the 
facility routinely experiences during normal operations, be fed during 
the performance test. This would preclude a source from artificially 
increasing the PM loading during the performance test using high ash 
feedstocks to obtain a high site-specific PM limit. If this were the 
case, the source could meet the PM limit during normal operations when 
feeding feedstocks with normal ash content while operating the PM 
control device under less efficient conditions. This could result in an 
increase in emissions of metals and D/F adsorbed onto PM. We invite 
comments on how to ensure that feedstocks with normal ash content are 
fed during the comprehensive performance test.
    The comprehensive performance tests would be conducted as follows. 
During the D/F, SVM, and LVM comprehensive performance tests, the 
facility would make manual measurements of D/F and metals and CEMS 
measurements of PM. Emissions of PM would be limited to the national 
standard of 69 mg/dscm during the tests. Following the tests the 
facility would establish two site-specific limits for PM: a ten-minute 
limit to control perturbations and a one-hour limit to control average 
emissions. The ten-minute average would be based on the highest ten-
minute rolling averages occurring during each comprehensive test. The 
hourly average would be the average of all one-minute averages 
occurring during each comprehensive test. (Note that, if the facility 
were to perform separate D/F and metals tests, the lowest of the two PM 
averages would be the applicable PM limit.)
    The facility need not determine or record two-hour averages to 
document compliance with the MACT PM standard during normal operation, 
only during the comprehensive test. Since the one-hour average is the 
average of all one-minute averages during the comprehensive performance 
test and the time duration of the test is longer than two hours, the 
one-hour average would have a numerical value lower than the two hour 
national standard. Demonstration of compliance with a lower numerical 
limit over a shorter averaging period proves compliance with a higher 
number over a longer averaging period.
    In lieu of a site-specific PM limit, EPA could limit key operating 
parameters for the PM control device to ensure that the device's 
collection efficiency is maintained at performance test level. We are 
concerned, however, that limiting key operating parameters (e.g., 
pressure drop across a fabric filter) may not be adequate because there 
are many complex operating and maintenance factors that affect 
collection efficiency of a PM control device. We believe that 
continuous monitoring of a surrogate emission (i.e., PM) is far 
preferable to continuous monitoring of operating parameters that less 
effectively relate to collection efficiency. (We note, however, that if 
the use of a PM CEMS is not required in the final rule, the rule would 
establish limits on the PM control device operating parameters as the 
next preferable approach.)
    Also, EPA invites comment on allowing small on-site sources 
(defined in Sec. 63.1208(b)(1)(ii) in the proposed regulations) to 
obtain a waiver from the requirement of installing a PM CEMS. If the 
waiver is promulgated and allowed by the permitting authority, the 
facility would demonstrate compliance with PM by establishing operating 
parameter limits described in subsection b, ``Operating Parameter 
Limits,'' below.
    iv. Proposed PM CEMS Performance and Calibration Specifications. 
There are existing performance specifications (PS) developed by the 
International Standards Organization (ISO) for PM CEMS. The ISO 
specifications have been modified slightly to account for the US 
regulatory environment. This PM CEMS PS is proposed here as Part 60, 
Appendix B, Performance Specification 11. EPA invites comment on this 
specification.
    It is proposed that HWCs follow the German approach to using PM 
CEMS. This approach involves deriving a site-specific statistically 
derived calibration curve of PM CEMS response to manual methods results 
for each fuel type. When the facility changes fuel type or supplier, a 
new PM CEMS calibration would be performed.
    It is proposed that PM CEMS be calibrated to the reference method, 
40 CFR 60, Appendix A, Method 5. Performance specification 11 requires 
that at least 15 measurements be made at least three grain loadings. 
During calibration, Method 5 and the CEMS will be run simultaneously 
during each of the 15 measurements. The average output response from 
the CEMS is then compared to the results of each of the 15 
measurements. Two calibration procedures are possible for PM CEMS: 
linear and quadratic. The performance specification proposes that 
facilities first calculate the calibration using the linear 
relationship, then the quadratic. If the quadratic relationship proves 
to be a better fit to the data, it is used. Otherwise the linear 
relationship is used.
    The quality assurance (QA) requirements for HWC CEMS propose that 
an absolute calibrations audit (ACA) be performed quarterly (every 
three months) and a relative calibration audit (RCA) be performed every 
18 months (30 months for small on-site facilities). If the calibration 
has drifted, a new calibration shall be performed. An absolute 
calibration audit would not be required during quarters when a response 
calibration audit is conducted.
    Also, there is a concern that the suitability of a calibration 
curve for a PM CEMS is dependant on the type of fuel used. For the 
purposes of this source category it is proposed that fuel type be 
defined by the physical state of the fuel: gas, liquid, or solid. 
Therefore, a facility that burns only gas, liquid, or solid fuel would 
need to generate only one calibration curve. Facilities which wish to 
burn a combination of fuel types would need to establish a single or 
multiple calibration curves which encompasses all combinations of fuel 
mix. Facilities which use multiple curves must describe in their 
quality assurance plan their methodology for deriving the curves and 
how the proper curves will be used during normal operation. See the TBD 
for more information on calibration due to fuel changes.
    b. Operating Parameter Limits. If the final rule does not require 
the use of a PM CEMS, we would rely on limits on ash feedrate and key 
PM APCD operating parameters to ensure continued compliance with the PM 
emission standard. In addition, if the provision allowing small on-site 
facilities (defined in Sec. 63.1208(b)(1)(ii) of the proposed 
regulations) to waiver the PM CEMS requirement is promulgated and the 
facility elects not to use a PM CEMS, the facility would have to 
establish these operating parameter limits to document compliance with 
the PM emission limit.

[[Page 17438]]

    i. Maximum Flue Gas Flowrate or Production Rate. EPA is concerned 
that flue gas flowrates exceeding those of the performance test could 
decrease the collection efficiency of the PM control device. For that 
reason, EPA proposes limiting flue gas flowrate. Alternately, CKs and 
LWAKs could limit production rate (e.g., production rate of clinker or 
aggregate, or raw material feedrate) since production rate is 
proportional to flue gas flowrate. Either flue gas flowrate or 
production rate would be established as a one hour average. The one-
hour average would be the average of the maximum hourly rolling 
averages occurring during the comprehensive performance tests.
    ii. Maximum Ash Feedrate. A portion of the ash fed into a HWC is 
emitted as PM. To limit the amount of PM emitted at the stack, maximum 
ash feedrate would be used as a compliance parameter. As set out in the 
BIF rule, however, EPA does not believe that an ash feedrate limit is 
necessary for CKs or LWAKs because entrained raw materials comprise 
virtually all of their PM emissions. See 266.103(c)(1)(iv) and 56 FR at 
7146. Thus, for a cement or lightweight aggregate kiln, variation in 
ash content of the hazardous waste is not likely to have a significant 
effect on PM loading at the inlet to the PM control device or PM 
emissions. Conceptually, however, the feedrate of ash in liquid feeds 
and the rate at which air pollution control dust (e.g., cement kiln 
dust) is returned to the kiln may have significant effect on the 
loading of small particles. Absent a CEMS, EPA seeks comment on 
addressing this issue.
    It is proposed that the limit on ash feedrate be established on a 
one-hour average to coincide with the other control parameters for PM. 
This one-hour average for ash feed is also consistent with and 
conservative relative to the two-hour (national) averaging period for a 
PM CEMS.
    iii. Wet Scrubber Parameters, including Venturi and Ionizing Wet 
Scrubbers. Venturi and other wet scrubbers remove PM by capturing 
particles in liquid droplets and separating the droplets from the gas 
stream. The wet scrubber parameters pertinent to PM control are minimum 
pressure drop across the wet scrubber, minimum liquid feed pressure to 
the wet scrubber, minimum blowdown or solids content of the scrubber 
liquid, and minimum liquid to gas ratio. Ionizing wet scrubbers have 
the additional parameter of minimum power input. Parameters for 
pressure drop, liquid feed pressure, and liquid to gas ratio are 
described, below, in the section dealing with HCl and Cl2 
standard. Parameters for blowdown or solids content and power input to 
an IWS are described in the next paragraphs.
    Blowdown is the amount of scrubber liquid removed from the process 
and not recycled back into the wet scrubber. Blowdown is an important 
wet scrubber parameter because, as scrubber liquid is removed and not 
recycled, solids are removed as well and not recycled. Alternately, 
solids content can be used as a direct indicator of solids content in 
the scrubber liquid. When the scrubber liquid contains high solids, 
there is a lack of a driving force for more solids to go into solution. 
Conversely, when little or no solids are in the scrubber liquid, there 
is a strong driving force for liquids to go into solution. Therefore, 
establishing a maximum solids content for a wet scrubber is desirable.
    If a PM CEMS is not required in the final rule, we propose that 
either a minimum blowdown or a maximum solids content limit be 
established. Both would be established on both a ten-minute and a one-
hour average. The ten-minute average would be the average of the 
minimum, for blowdown, or maximum, for solids content, ten-minute 
averages occurring during each run of the comprehensive performance 
test. The one-hour average would be the average over all runs.
    Power input to an IWS is important because IWSs charge the 
particulate prior to it entering a packed bed wet scrubber. The 
charging aids in the collection of the particulate onto the packing 
surface in the bed. The particulate is then washed off of the packing 
by the scrubber liquid. Therefore, power input to an IWS is a key 
parameter to the proper operation of an IWS and EPA proposes that 
facilities establish a limit on minimum power input to an IWS. This 
limit would be established on both a ten-minute and one-hour average. 
The ten-minute average would be the average of the minimum 10 minute 
averages occurring during each run of the comprehensive performance 
test and the one-hour average would be the average across all runs.
    Facilities may obtain a waiver from these requirements for wet 
scrubbers from the Director if they can identify other key parameters 
which affect good control of PM through their use and use these 
parameter limits during normal operation.
    iv. Fabric Filters. Fabric filters (FFs), also known as baghouses, 
are used to filter PM from stack flue gas prior to the stack. 
Performance of a fabric filter directly affects PM emissions. Filter 
failure is typically due to filter holes, bleed-through migration of 
particulate through the filter and cake, and small ``pin holes'' in the 
filter and cake. Since low pressure drop is an indicator of one of 
these types of failure, pressure drop across the fabric filter is the 
best indicator that the fabric filter has not failed.
    If the final rule does not require the use of a PM CEMS, EPA 
proposes that a limit on minimum pressure drop across the fabric filter 
be established to ensure that collection efficiency is maintained. EPA 
proposes that this limit be established on both a ten-minute and a one-
hour average. The ten-minute average would be the average of the single 
lowest 10-minute rolling averages occurring during each run of the 
comprehensive performance test. The one-hour average would be the 
average over all runs.
    EPA believes it would also be useful to establish other, 
potentially better parameters as measures of collection efficiency for 
the fabric filter. Collection efficiency from fabric filters is a 
function of filter type, face velocity (which in turn is a function of 
flue gas flowrate and filter material area), cake build-up on the 
filter, and particulate matter characteristics (primarily particulate 
size distribution). Unfortunately, the Agency is not aware of a way to 
establish parameters for these indicators of collection efficiency. 
Therefore, EPA invites comment on what type of parameters could be used 
as better indicators of collection efficiency and on what averaging 
period they should be established.
    Facilities may obtain a waiver from these requirements for PM APCDs 
from the Director if they can identify key parameters which affect good 
control of PM through their use and use these parameter limits during 
normal operation.
    v. Electrostatic Precipitators. Electrostatic precipitators (ESPs) 
capture PM by charging particulate in an electric field and collecting 
the charged particulate on an inversely charged collection plate. 
Electrical power is the product of the electrical voltage and the 
current. High voltage leads to high magnetic field strength which 
results in an increase in the saturation charge level the particle can 
obtain, which in turn causes an increase in charged particle migration 
to the collection plate. High current leads to an increased particle 
charging rate and increased electric field strength near the collection 
electrode due to a phenomena called ``ionic space charge'' and, thus, 
increased collection at the plate. High voltage is also important on 
the collection plates, since this will increase

[[Page 17439]]

collection of the inversely charged particles on the plates. Therefore, 
maximizing both voltage and current is desirable for good collection. 
Therefore, power input to the ESP is a direct function of ESP 
efficiency since, the lower the power input, the lower the collection 
efficiency.
    For these reasons, EPA proposes that facilities establish a limit 
on minimum power input to the ESP to ensure that collection efficiency 
is maintained at performance test levels if the final rule does not 
require the use of a PM CEMS. This limit would be established on both a 
ten-minute and one-hour average. The ten-minute average would be the 
average of the minimum 10-minute averages for power input which occurs 
during each run of the comprehensive performance test. The one-hour 
average would be the average over all runs.
    Since very high power can be supplied to either the charging or 
collection parts of an ESP, EPA also invites comment on whether power 
input to each part of the ESP should be controlled.
    Facilities may obtain a waiver from these requirements for ESPs 
from the Director if they can identify more appropriate parameters that 
would ensure that collection efficiency is maintained at performance 
test levels.
8. Waiver of Operating Limits
    We believe that a provision to waive any or all of the operating 
limits discussed in this section is appropriate given that many sources 
will employ unique and innovative combinations of emission control 
devices. Fixed, national monitoring and compliance requirements may not 
be applicable or reasonable in some situations. Accordingly, the 
proposed rule would allow the Director to grant a waiver from any or 
all of the operating limits discussed in this section if a source 
documents in writing that other, more appropriate operating limits 
would ensure compliance with the pertinent emission standard. See 
proposed Sec. 63.1210(s). The documentation must include recommended 
averaging periods for the alternative operating limits, and the basis 
for establishing the limits based on operations during the 
comprehensive performance test.
9. Request for Comment on Waiver of CEMS Requirements for Small, On-
Site Sources
    We specifically invite comment on whether the final rule should 
allow small, on-site sources the option of not having to use a mercury 
and PM CEMS. Under a waiver, the source would be required to comply 
with the operating limits discussed above in lieu of using a CEMS. As a 
separate issue, EPA is proposing less stringent RATA and RCA 
frequencies for the mercury and PM CEMS (and testing in general, see 
section III of this part) for these sources.
    Sources with a gas flowrate less than 23,127 acfm would be 
considered small. See discussion in Part Four, Section I, for the 
rationale for that demarcation between small and large units. See also 
Sec. 63.1208(b)(1)(ii) of the proposed rule. We believe that this 
waiver could be warranted because small, on-site sources may be better 
able to effectively sample and analyze feedstreams to ensure compliance 
with feedrate limits, and because their emission rates (i.e., 
environmental loading) would be less than from large sources.
    We also invite comment on basing the definition of what is small on 
a gas flowrate and the value proposed for defining what is a small 
source.

D. Combustion Fugitive Emissions

    Operating parameters on combustion fugitive emissions are necessary 
to ensure that these emissions do not leak from the combustion device, 
APCDs, or any ducting connecting them. The current BIF and incinerator 
rules establish provisions for controlling combustion fugitive 
emissions (see Secs. 266.102(e)(7)(I) and 264.345(d)). Today's proposed 
rule would require sources to comply with those requirements, with 
minor clarifications. See proposed Sec. 63.1207(b). Specifically, it is 
proposed that sources shall:

--keep the combustion chamber and all ducting and devices from the 
combustion chamber to the stack totally sealed against fugitive 
emissions; or
--maintain the maximum pressure on an instantaneous basis in the 
combustion chamber and in all ducting and devices from the combustion 
chamber to the stack at lower than ambient pressure at all times; 
159 or
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    \159\ That is, on an instantaneous basis, without an averaging 
period. The recording system must record the instantaneous values 
continuously.
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--use some other means of control demonstrated to provide equivalent 
control. Support for such demonstration shall be included in the 
operating record with prior written approval obtained from the 
Director.

In addition, the rule would require the owner or operator to specify in 
the operating record the method used for fugitive emission control.
    EPA continues to believe this approach (already in effect for 
incinerators and BIFs) is appropriate and is proposing to retain it 
here. There are cases, however, particularly at munitions incinerators, 
where combustion fugitive emissions are a problem even when less than 
ambient pressure is apparently being maintained. In these cases, the 
Director may require in the RCRA operating permit continual video 
surveillance of the equipment to ensure there are no leaks. If leaks 
occur, each occurrence is a violation, and would require an automatic 
waste feed cut-off (AWFCO). In addition, as with all AWFCOs, the owner 
or operator must identify the cause of the leak and identify remedial 
action taken to minimize future occurrences.
    We are also proposing to make conforming changes to the existing 
BIF and incinerator requirements for combustion fugitive emissions. See 
proposed Secs. 264.347(e), 265.347(c), and 266.102(e). The effective 
date of these conforming requirements would be 6 months after 
publication of the final rule in the Federal Register, and so would 
take effect before the MACT standard compliance date.

E. Automatic Waste Feed Cutoff (AWFCO) Requirements and Emergency 
Safety Vent (ESV) Openings

    We explain in this section that the source must be in compliance 
with the CEMS-monitored emission standards and the operating limits at 
all times. This would be ensured by requiring that all operating 
parameters for which limits would be established (as discussed above) 
must be interactive with an automatic waste feed cutoff (AWFCO) system. 
Further, we also describe the periodic reporting requirements that 
would apply if 10 AWFCOs that result in an exceedance of a CEMS-
monitored emission standard or operating limit occur during any 60-day 
period. Finally we explain the consequences of, and reporting 
requirements for, emergency safety vent openings.
1. Automatic Waste Feed Cutoff System
    Sources must be in compliance with the CEMS-monitored emission 
standards and operating limits at all times. See proposed Sec. 63.1207 
(a)(1) and (a)(2). If a facility exceeds a standard or operating limit, 
today's rule proposes that the hazardous waste feed be instantaneously 
and automatically cut off. This requirement now exists under current 
incinerator permits and the Agency's BIF rules (see 
Sec. 266.102(e)(7)(ii)). After an AWFCO, the source must continue to 
monitor all AWFCO operating parameters (and

[[Page 17440]]

CEMS-monitored emissions) and cannot begin feeding hazardous waste 
again until all parameters come within allowable levels. Further, to 
minimize emissions of regulated pollutants, including products of 
incomplete combustion that could result from the perturbation caused by 
the waste feed cutoff, combustion gases must continue to be routed 
through the air pollution control system after a cutoff, and minimum 
combustion temperature must be maintained for as long as hazardous 
waste remains in the combustion chamber.
    As currently required under the BIF rule, all AWFCO parameters must 
continue to be monitored after an AWFCO, and hazardous waste firing 
cannot resume until all parameters are within allowable levels. Thus, 
all rolling averages must continue to be calculated even when hazardous 
waste is not being burned.160
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    \160\ This requirement that all parameters must continue to be 
monitored after a AWFCO assumes that the operator intends to begin 
burning hazardous waste as soon as the operating parameters return 
to allowable levels. If not, however, it may not be practicable to 
require monitoring of AWFCO parameters when hazardous waste is not 
burned. We specifically request comment on a reasonable interval of 
time after a AWFCO and before hazardous waste firing could be 
resumed during which the operator would not be required to monitor 
the AWFCO parameters. For example, if the operator did not intend to 
begin burning hazardous waste for 8 hours after the AWFCO, it may 
not be appropriate to require monitoring of AWFCO parameters during 
that period.
---------------------------------------------------------------------------

    Today's proposed rule would require the following parameters to be 
AWFCO parameters: 161
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    \161\ We note that during the RCRA permitting process, permit 
writers may identify additional operating parameters they determine 
to be necessary on a case-specific basis in order for the source to 
comply with the standards. See subsection C.1. of this part, 
``Continued Applicability of RCRA Omnibus Authority,'' for more 
information on this.
---------------------------------------------------------------------------

--CEMS-monitored emission standards
--All applicable feedrate limits (e.g., hazardous waste, pumpable LVM 
metals, total SVM and LVM metals)
--Minimum combustion chamber temperature (each chamber)
--Maximum combustion chamber temperature
--Maximum temperature at the inlet to the initial dry PM control device
--Maximum combustion chamber pressure (if used to control combustion 
fugitive emissions)
--Maximum flue gas flowrate (or production rate)
--Minimum flue gas flowrate (where required (e.g., under 
Sec. 63.1208(h)(1)) (or production rate)
--Limits on operating parameters of the emission control equipment 
(e.g., carbon injection rate)
--Failure of the Automatic Waste Feed Cut-off system.
--Whenever continuous monitoring systems (CMS) or the measurement 
component of the CMS registers a value beyond its rated scale.

    We note that the current requirements for BIFs and incinerators do 
not require a AWFCO whenever a measurement component of the CMS 
registers a value beyond its rated scale or when the AWFCO system 
fails. To ensure that those standards conform with today's proposal, we 
are proposing to add this requirement to those rules. The effective 
date of these conforming requirements would be six months after 
publication of the final rule in the Federal Register, and thus would 
precede the MACT standard compliance date.
    If an operating limit or CEMS-monitored emission standard is 
exceeded after the hazardous waste feed has ceased but while hazardous 
waste remains in the combustion chamber, it is a violation of the 
relevant emission standard.162
---------------------------------------------------------------------------

    \162\ If an operating limit is exceeded (when hazardous waste is 
in the combustion chamber), the source has violated the emission 
standard for which the operating limit is used to ensure compliance.
---------------------------------------------------------------------------

    As currently required for BIFs, the AWFCO system and associated 
alarms must be tested at least once every seven days when hazardous 
waste is burned to verify operability, unless the owner or operator 
documents in the operating record that weekly inspections will unduly 
restrict or upset operations and that less frequent inspections will be 
adequate. At a minimum, operational testing must be conducted at least 
once every 30 days.
    Under today's proposed rule, owners and operators would be required 
to document in the operating log the cause of each AWFCO that is 
associated with an exceedance of an operating limit or CEMS-monitored 
emission standard 163 and document the preventive measures taken 
to minimize future AWFCOs. Also, we are proposing a reporting 
requirement for excessive AWFCOs caused by violations to alert 
regulatory officials that a source is having operational problems. 
Thus, regulatory officials can increase frequency of inspections and 
review the sources operating plan. In addition, the Director may 
specify requirements through the RCRA permit beyond recordkeeping and 
reporting for addressing AWFCOs (i.e., approval to restart hazardous 
waste feed, etc.)
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    \163\ Not all AWFCOs are the result of an exceedance of an 
emission standard or operating limit. AWFCOs which are not 
associated with a violation must be recorded in the operating log 
but need not be reported.
---------------------------------------------------------------------------

    Owners or operators would be required to submit an ``Excessive 
AWFCO Report'' to the Administrator if more than 10 AWFCOs associated 
with an exceedance of an operating limit or CEMS-monitored emission 
standard occur during any 60 calendar-day period. After 10 such cutoffs 
occur, the 60 calendar-day clock would begin anew. The report would 
have to be postmarked within five calendar days of the tenth AWFCO 
associated with an exceedance, and would have to document the cause of 
each such cutoff and preventive measures taken to minimize future 
cutoffs.
    We invite comments on alternative exceedance frequencies that would 
trigger the need to submit an Excessive AWFCO Report, such as incurring 
5 cutoffs in any 30 calendar-day period. A shorter accounting period 
would enable enforcement officials to better identify problem 
facilities.
2. Emergency Safety Vent (ESV) Openings
    Today's rule would require that combustion gases always pass 
through the emission control system in place during the comprehensive 
performance test. Thus, opening an emergency safety vent (ESV) 
(including emergency vent stacks, bypass stacks, thermal relief valves, 
and pressure relief valves) to bypass any part of the emission control 
system would be a violation of that requirement and the emission 
standard the by-passed control device is designed to control. See 
proposed Sec. 63.1207(a)(3). We are also proposing to make conforming 
changes to the RCRA incinerator standards of Part 264, Subpart O, to 
provide consistency. While this section specifically addresses ESVs, 
the requirements apply to any type of air pollution control bypass 
stack while hazardous waste remains in the combustion chamber.
    ESVs are safety devices which are designed to allow combustion 
gases to bypass the air pollution control equipment in order to: (1) 
Prevent ground-level releases which could endanger workers, in the 
event of an overpressure, or (2) prevent damage to the air pollution 
control equipment in the event of excessively high temperatures. An ESV 
opening allows uncontrolled emissions to directly enter the atmosphere. 
Some ESVs are situated prior to the secondary combustion chamber. This 
chamber is important for organics destruction in an incinerator. 
Further, since incinerators normally demonstrate compliance with the 
regulatory performance standards while

[[Page 17441]]

using their secondary combustion chambers and air pollution control 
devices, emissions from ESVs are expected to be in excess of levels set 
by the performance standards for the respective devices.
    There are situations where the alternative to opening an ESV (e.g., 
fugitive emissions at ground level, or even an explosion) are worse 
from a health and environmental standpoint. Thus, EPA would like to 
emphasize that simply eliminating an ESV itself is one solution, but 
not appropriate in some cases. Rather, EPA believes that emergency (or 
other) situations which would cause either an ESV opening or fugitive 
emissions from the combustor can, and should be, prevented to the 
greatest extent possible.
    EPA believes that most facilities can readily make changes in their 
operations which can reduce ESV openings. To minimize ESV openings, 
facilities may need to repair or replace unreliable equipment, better 
control the feeding of waste, or add redundant systems where necessary.
    In the preamble to the proposed amendments for hazardous waste 
incinerators (55 FR 17890, April 27, 1990), EPA proposed to clarify the 
regulatory status of ESV openings. The Agency proposed that no ESV 
openings be allowed while hazardous waste is in the unit. In this case 
any ESV opening while hazardous waste remains in the unit would be a 
permit violation and subject to enforcement action. This is being 
reproposed today.
    Also in the proposed rule for hazardous waste incinerators (55 FR 
at 17891), EPA proposed to amend Sec. 264.345(a) to clarify that an 
incinerator must operate in accordance with the operating requirements 
specified in their permit whenever there is hazardous waste in the 
incinerator. Today's rule is again proposing to amend Sec. 264.345(a) 
to clarify that an incinerator must be operated in accordance with the 
conditions specified in the permit and meet the applicable emission 
standards at all times that hazardous waste or hazardous waste residues 
remain in the chamber. (This is a conforming change.)
    For BIFs, the regulations state that they must be operated in 
accordance with the operating limits and the applicable emission 
standards at all times when there is waste in the unit. 
Sec. 266.103(c)(1). Further, Sec. 266.102(e)(7)(ii)(B) requires that 
combustion gases must be routed through the air pollution control 
system as long as waste remains in the unit. The BIF final rule 
discusses that a BIF must be in compliance at all times that there is 
hazardous waste in the unit, regardless of whether an automatic waste 
feed cutoff has occurred. See 56 FR at 7160. The activation of the 
automatic waste feed cutoff system does not relieve the facility from 
its obligation to comply with the permit conditions while waste remains 
in the unit. Today's rule does not propose any changes to this regime.
    Finally, today's proposed rule would require the owner or operator 
to record in the operating log the ESV opening, the reason for the 
opening, and corrective measures taken to minimize the frequency of 
openings. Further, the owner or operator would have to submit a written 
report to the Administrator within 5 calendar days of each ESV opening 
documenting the information provided in the operating log.
    While it is understood that there can be mitigating circumstances 
which require the use of ESVs, these instances should be minimized. 
Therefore, it is proposed that the owner or operator prepare an ESV 
Operating Plan in which the owner or operator shall address what they 
will do to prevent the use of the ESV and release uncontrolled 
emissions into the air and what they will do to minimize the hazard 
from such releases (such as back-up systems, maintaining flame 
temperature, and combustion air to combustion organics.) This plan is 
analogous to the ``Preparedness and Prevention and Contingency Plan'' 
discussed in the 1990 proposed revisions to the hazardous waste 
incinerator rule (55 FR at 17890). A corresponding change to the 
current hazardous waste incinerator rules are proposed as well.

F. Quality Assurance for Continuous Monitoring Systems

    EPA proposes specific quality assurance (QA) requirements for 
continuous monitoring systems (CMS). These systems can be classified 
as: continuous emissions monitoring systems (CEMS); analysis of 
feedstreams; and continuous monitoring systems to comply with limits on 
other operating parameters.
1. Continuous Emissions Monitoring Systems (CEMS)
    The rule would require HWCs to comply with the general monitoring 
requirements under Sec. 63.8 for all MACT sources except as discussed 
below. In addition, the rule would establish in the appendix to Part 
63, Subpart EEE, specific quality assurance (QA) and quality control 
(QC) requirements for CEMS used by HWCs. These requirements would 
supersede the requirements in Appendix F of Part 60 for these sources. 
We are proposing an appendix to Subpart EEE in lieu of the requirements 
of Appendix F because the proposed appendix to Subpart EEE would 
incorporate various issues particularly relating to HWCs (e.g., 
requirements for specific CEMS not addressed by Appendix F; out-of-
control periods and data reporting are not relevant to HWCs because 
HWCs cannot burn hazardous waste if the CEMS is not meeting performance 
specifications).
    a. Applicability of Sec. 63.8 Requirements. Most of the Sec. 63.8 
monitoring requirements for MACT sources would apply to HWCs including 
requirements for the owner and operator to develop and implement a 
quality control program (Sec. 63.8(d)(2)) and conduct a performance 
evaluation test in conjunction with the performance test to 
demonstration compliance with the emission standards (Sec. 63.8(d)(2) 
and (e)(4)). Section 63.8(f) also provides for approval of an 
alternative monitoring method.
    Several provisions of Sec. 63.8, however, would not apply to HWCs. 
They are as follows:
    i. Sec. 63.8 (c)(1)(I)-(iii), (c)(4), (c)(7), (c)(8), and (g)(5) 
would not apply because these paragraphs address requirements relating 
to operations when the CEMS is out of compliance with the relevant 
performance specifications. Hazardous waste cannot be fed (or remain in 
the combustion chamber) if the CEMS is not in compliance with 
performance specifications.
    ii. Sec. 63.8 (c)(4)(ii) and (g)(2) would not apply because these 
paragraphs define continuous operation and data reduction 
inconsistently with today's proposed rule. Under today's rule, the 
performance specifications in Appendix B to Part 60 and the data 
quality objectives in the appendix to Part 63, Subpart EEE, define 
continuous operation specific to the CEMS.
    b. Quality Assurance Procedures. The proposed appendix to Part 63, 
Subpart EEE, defines quality assurance procedures for CEMS at HWCs. If 
a CEMS component is not in compliance with applicable quality assurance 
procedures or performance specifications (provided in Appendix B, Part 
60), hazardous waste burning must cease immediately and cannot be 
resumed until the owner or operator documents that the CEMS meets the 
performance specifications.
    The appendix would require owners and operators to develop and 
implement a quality assurance and quality control (QA/QC) program. It 
would define requirements for determining compliance with calibration 
and zero

[[Page 17442]]

drift specifications provided in Appendix B. It would also define 
requirements for performance evaluations, that is, performance audits 
including relative accuracy tests and absolute calibration audits.
    The appendix also deals with issues specific to these source 
categories. It establishes specific testing intervals for CEMS for 
HWCs. It defines the one minute and rolling averages, the oxygen 
correction factor, CEMS span values, and provides a provision to allow 
the use of alternative span values. It provides procedures for 
reestablishing a rolling average after short term interruptions such as 
calibration and maintenance and long-term interruptions such as 
periodic downtime for kiln maintenance or for weekends and holidays 
when the facility is not being operated. It also allows up to 20 
minutes of CEMS downtime for calibration purposes.
    c. Conforming changes to the BIF and incinerator rules. Conforming 
changes are also proposed to the BIF and incinerator rules: deleting 
the current Part 266, Appendix IX, CEMS requirements; and, instead, 
requiring the use of the Part 60, Appendix B, performance 
specifications and the data quality specifications in the appendix to 
Subpart EEE.
    d. Zero Drift and Zero Gas Requirements. The Agency specifically 
invites comment on two other issues which affect all CEMS: whether the 
zero drift requirements contained in the appendix to Subpart EEE (and 
the various performance specifications) should be promulgated, or 
whether the zero gas requirements should be changed from the current 0-
20 percent levels to a 0-0.1 ppm level.
    Many of the performance specifications require that zero gas, or 
zero level gas, contain between 0 to 20 per cent of the measured 
constituent. However, facilities often use just one zero grade gas for 
all their CEMS, one of ``zero-grade nitrogen.'' Therefore, EPA invites 
comment on whether this requirement should be changed from 0 to 20 
percent to 0 to 0.1 ppm of the measured constituent.
    e. EPA certification of CEMS. EPA invites comment on whether a 
process should be established whereby CEMS manufacturers could certify 
that their CEMS meet the established performance specifications. If 
this were promulgated, a CEMS would not be allowed for use on a 
hazardous waste combustor unless it has been certified by EPA. The CEMS 
certification would be similar to the certifications used for TUV 
approval in Germany and for CEMS used for compliance with EPA's acid 
rain program.
    Issues EPA needs to address in order to promulgate such a process 
include: what benefits the regulated community and industry would incur 
as a result of such a certification; how the program would work; and 
whether a nongovernment agency could do this task.
    vi. Correcting CEMS Readings for Moisture Content. One quality 
assurance issue that must be considered is how often facilities need to 
measure the moisture content of their flue gas. All the standards 
proposed today are on a dry basis, so knowing the flue gas moisture 
content to correct CEMS outputs to a dry basis is necessary. EPA is 
considering two alternative approaches to obtain the moisture content 
of the flue gas. One involves making periodic measurements of the 
moisture content of the flue gas using Method 4, found in Part 60, 
Appendix A. Under this scheme, a facility would take flue gas moisture 
measurements quarterly, while conducting the ACA. This moisture level 
would then be used to correct CEMS outputs for moisture throughout the 
next quarter.
    Another alternative is that facilities make instantaneous 
measurements of the flue gas temperature at the CEMS sampling point. 
The temperature would then be used to determine the saturation water 
concentration of the flue gas. The saturation water concentration would 
then be used to correct the CEMS output for moisture.
    EPA favors using the saturation water concentration as a surrogate 
for flue gas moisture because it is continuous, frequently 
conservative, and cost-effective compared to running a manual method. 
One issue with this approach is that facilities with wet APCS may have 
a water concentration higher than the saturated water concentration due 
to entrained water droplets in the flue gas. However, we do not have 
data on the amount of entrained water droplets in the flue gas and, 
thus, cannot determine at this point how important this issue is.
    The Agency requests data and information from facilities with a wet 
APCS regarding the total water concentration (including water droplets) 
in the flue gas compared with the saturated water concentration. The 
Agency will evaluate data and recommendations of commenters on these or 
other approaches in making a determination on the best approach for the 
final rule.
2. Analysis of Feedstreams
    In this section, we discuss the following proposed requirements for 
analysis of feedstreams: (1) required analysis plan; (2) requirement to 
submit the plan for review and approval the Director's request; (3) 
frequency of analysis; and (4) information that must be determined and 
recorded to document compliance. (We note that HWCs are already subject 
to these requirements under 40 CFR Parts 261, 264, 265, 266, and 270.) 
We also request comment on analysis of gaseous feedstreams, including 
natural gas. We also propose making a conforming change to the BIF and 
incinerator rules to clarify that constituent monitoring is required 
for all feedstreams.
    a. Feedstream Analysis Plan. The rule would require (in 
Sec. 63.1210(c)) an owner or operator to obtain an analysis of each 
feedstream that is sufficient to document compliance with the 
applicable feedrate limits. The owner or operator must obtain the 
analyses for each feedstream prior to feeding into the combustor. This 
is done in order to document compliance with the applicable feedrate 
limits at all times.
     To ensure that the owner or operator will obtain an adequate 
analysis, the owner or operator would be required to develop and 
implement a feedstream analysis plan and record it in the operating 
record. The operating plan must specify at a minimum: (1) the 
parameters for which each feedstream will be analyzed to ensure 
compliance with proposed Sec. 63.1210; (2) whether the owner or 
operator will obtain the analysis by performing sampling and analysis, 
or by other methods such as using analytical information obtained from 
others 164 or using other published or documented data or 
information; (3) how the analysis will be used to document compliance 
with applicable feedrate limits (e.g., if hazardous wastes are blended 
and analyses are obtained of the wastes prior to blending but not of 
the blended, as-fired, waste, the plan must describe how the owner and 
operator will determine the pertinent parameters of the blended waste); 
(4) the test methods which will be used to obtain the analyses; 
165 (5) the sampling method which will be used to obtain a 
representative sample of each feedstream to be analyzed using sampling 
methods described in Appendix I, Part 261, or an equivalent method; and 
(6) the frequency with which the initial analysis of the feedstream 
will be reviewed or repeated

[[Page 17443]]

to ensure that the analysis is accurate and up to date.166
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    \164\ When analytical information is provided by others, the 
analysis plan must document how the owner or operator will ensure it 
is complete and accurate.
    \165\ The information must be provided whether the owner or 
operator conducts the analyses or the analyses are obtained from 
others.
    \166\ The analysis must be repeated as necessary to ensure that 
it is accurate and up to date. At a minimum, the analysis must be 
repeated when the owner or operator is notified or has reason to 
believe that the process or operation generating or producing the 
feedstream has changed.
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    We note that guidance on developing a feedstream analysis plan is 
provided in Waste Analysis At Facilities That Generate, Treat, and 
Dispose of Hazardous Waste, (OSWER [Office of Solid Waste and Emergency 
Response] #9938.4-03, April 1994). The document is available from the 
National Technical Information Services (NTIS), publication # PB94-963-
603. In addition, in April 1995, EPA published a Notice of Availability 
for public comment on Waste Analysis Guidance for Facilities That Burn 
Hazardous Wastes-Draft (Office of Enforcement and Compliance Assurance 
# EPA 530-R-94-019) (see 60 FR 18402). This guidance document provides 
assistance in developing waste analysis plans specifically for HWCs. 
The comment period for this document closed on June 2, 1995, and EPA is 
currently reviewing and evaluating the comments received.
    b. Review and Approval of Analysis Plan. Under today's proposed 
rule, the Director could require the owner or operator to submit the 
analysis plan for review and approval at any time. Given that 
feedstream analysis is a primary compliance approach for the SVM, LVM, 
and HCl/Cl2 emission standards, it is imperative that the source 
develop and implement an adequate analysis plan. Consequently, the 
Agency would like to review and approve analysis plans for each 
existing source at the time of initial compliance (i.e., initial 
notification of compliance).167
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    \167\ Analysis plans would be reviewed and approved for new 
sources during the RCRA permitting process (i.e., prior to 
commencement of construction).
---------------------------------------------------------------------------

    Because of resource constraints, however, the Agency will review 
analysis plans on a priority basis, considering factors such as whether 
the source accepts off-site waste, volume of waste burned, and 
compliance history.168 Therefore, the Agency wishes to preserve 
flexibility on whether to require a source to submit its analysis plan 
for review and approval.
---------------------------------------------------------------------------

    \168\ Note that the analysis plan will be reviewed during 
facility inspections as well.
---------------------------------------------------------------------------

    c. How to Comply with Feedrate Limits. To comply with the feedrate 
limits, the source must: (1) know the concentration of the limited 
parameter (e.g., SVM) in the feedstream at all times; (2) know the 
feedrate of the feedstream at all times; and (3) record the feedrate 
(the product of the concentration times the feedstream rate) in the 
operating record. The source would know the concentration of the 
parameter in the feedstream by implementing the analysis plan discussed 
above.
    The source would know the feedrate of the feedstream by using a 
continuous monitor of the volumetric or mass flowrate.169 If a 
volumetric flowrate monitor is used, the source must know the density 
of the feedstream at all times if it is necessary to know the mass per 
unit time feedrate.
---------------------------------------------------------------------------

    \169\  Quality assurance for the flowrate monitor is discussed 
below in the text.
---------------------------------------------------------------------------

    In order for a facility to know the concentration of the parameters 
at all times, the source must record the feedrate in the operating 
record. It would be preferable to reduce the burden on regulatory 
inspectors to continuously record all of the parameters used to 
calculate the feedrate (e.g., concentration of metal, volumetric 
flowrate, density) as well as the feedrate itself. Other approaches may 
be acceptable, however, such as continuously recording only volumetric 
flowrate, but clearly noting in the record the concentration and 
density associated with that volumetric flowrate so that the inspector 
could readily confirm that the feedrate was not exceeded at the 
recorded flowrates. If a source prefers the second approach, we 
recommend that it informally notify the Director for concurrence.
    d. Request for Comment on Monitoring Gaseous Feedstreams. We 
request comment here on how to address the difficulty of continuously 
sampling gaseous feedstreams--both natural gas and process gas--for 
nonvapor constituents (metals, chloride salts).
    Natural gas is a primary fuel for several HWCs. Under today's rule 
(as well as the BIF regulations), this feedstream, like all other 
feedstreams, would be subject to the continuous monitoring and 
recording provisions, including feedstream sampling and analysis for 
metal and chlorine constituents.
    Facilities have questioned whether it is necessary to sample and 
analyze natural gas for constituents they feel are not reasonably 
expected to be present. Therefore, the Agency is soliciting data and 
information on whether (and at what concentrations) the seven metals 
that would be regulated in today's rule are likely to be present in 
natural gas. Based on the information submitted by commenters, the 
final rule could incorporate a number of options including: (1) 
determine that natural gas feedstreams need not be considered in 
feedrate determinations because levels of metals and chlorine and 
chloride are not likely to be significant; (2) allow sources to make a 
one-time, site-specific determination of metals and chlorine levels 
that could be used for feedrate determinations provided that the 
natural gas supplier does not change; or (3) establish generic 
concentration levels for metals and chlorine and chloride that could be 
assumed to be present. We also invite comment on these or other 
approaches to address this issue.
    Process gas feedstreams pose a similar problem. One approach for 
these feedstreams would be to allow sources to make a one-time 
determination of metals and chlorine levels (by sampling and analysis, 
process knowledge, or other information) that could be used for 
feedrate determinations until process changes or other factors occurred 
that could change the composition of the gas. We invite comments on 
this or alternative approaches to address this issue.
3. Quality Assurance for Continuous Monitoring Systems Other Than CEMS
    Continuous monitoring systems (CMS) other than CEMS include the 
systems associated with monitors such as thermocouples, pressure 
transducers, stress/strain gages, flow meters, and pH meters. In 
addition to the requirements discussed below, we are proposing to 
require compliance with the general quality assurance procedures for 
continuous monitoring systems (CMS) provided by existing 
Sec. 63.8(c)(4). See proposed Sec. 63.1210(d). That paragraph requires 
owners and operators to verify the operational status of CMS by, at a 
minimum, complying with the manufacturer's written specifications or 
recommendations for installation, operation, and calibration of the 
system. To make current rules consistent with the ones which will be 
promulgated here, EPA proposes making conforming changes to the BIF and 
incinerator rules to incorporate quality assurance requirements for 
CMS.
    a. Sampling and Detection Frequency. We are proposing to require 
that CMS (other than CEMS)170 sample the regulated parameter 
without interruption, and evaluate the detector response at least once 
each 15 seconds, and compute and record the average values at least 
every 60 seconds.
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    \170\ The proposed CEM performance specifications and data 
quality objectives define acceptable sampling and detection 
frequency.
---------------------------------------------------------------------------

    b. Exceeding CMS Span Would Trigger a AWFCO. The rule would also

[[Page 17444]]

require that the automatic waste feed cutoff (AWFCO) system be engaged 
if the span of any CMS (other than a CEMS) is exceeded. This is because 
it is not practicable to establish span values for each CMS as we have 
proposed for each CEMS.
    The issue arises because facilities have the discretion of 
purchasing equipment with any span. For CMS, the span is defined as the 
range between the highest certifiable reading a CMS can make (the 
``upper span'') and its corresponding minimum (the ``lower span.'') If 
a CMS were to have an upper span which is too low, say a thermocouple 
with a upper span of 630 deg.C, there would be no way to document 
accurately a temperature higher than 630 deg.C. This is a problem if 
the facility routinely operates at a temperature of, say, 750 deg.C. 
For this reason, it is important to ensure that CMS are operated within 
their certified span.

III. MACT Performance Testing and Related Issues

    Today's rule would require performance testing to demonstrate 
compliance with the proposed MACT emission standards. The requirements 
and procedures for MACT performance testing are discussed here. In 
addition, HWCs would continue to be subject to the existing trial burn 
requirements during the RCRA permitting process. The interaction 
between the RCRA trial burn and the MACT performance test is also 
discussed here. In addition, we discuss in this section the waiver for 
performance testing for Hg, SVM, LVM, and HCl/Cl2 that would be 
provided for sources that feed de minimis levels of these metals or 
chlorine. Finally, we discuss in this section requirements for relative 
accuracy tests for CEMS.

A. MACT Performance Testing

    Two types of performance testing would be required to demonstrate 
compliance with the proposed MACT emission standards: comprehensive 
performance testing and confirmatory performance testing. See proposed 
Sec. 63.1208.
1. Comprehensive Performance Testing
    The purpose of the comprehensive performance test is to initially 
and periodically thereafter: (1) demonstrate that the source is in 
compliance with the CEMS-monitored emission standards (e.g., PM, Hg, 
CO, HC); (2) conduct manual stack sampling to demonstrate compliance 
with the emission standards for pollutants that are not monitored with 
a CEMS (e.g., D/F, SVM, LVM, HCl/Cl2); (3) establish limits on the 
applicable operating parameters provided by proposed Sec. 63.1210 
(Monitoring Requirements) to ensure that compliance is maintained with 
those emission standards for which a CEMS is not used for compliance 
monitoring; and (4) demonstrate performance of CMS is consistent with 
the requirements and quality assurance plan. Thus, the comprehensive 
performance test has purposes similar to the RCRA trial burn and BIF 
interim status compliance test. It would be more like a BIF interim 
status compliance test, however, because of the low level of Agency 
oversight and high degree of facility self-implementation, as discussed 
below.
    a. Operations During Comprehensive Performance Testing. Given that 
limits will be established on operating parameters during the 
comprehensive performance test, sources will likely want to operate 
during the test at the edge of the operating envelope that they believe 
is both necessary to operate efficiently and comply with the emission 
standards. Accordingly, sources may elect to spike feedstreams with 
metals or chlorine, for example, to ensure that the feedrate limits are 
high enough to accommodate normal operations while allowing some 
flexibility to feed higher rates at times.
    In addition, sources may identify two or more modes of operation 
for which separate performance tests would be conducted and for which 
separate limits on operating conditions would be established. In this 
situation, the source would be required to note in the operating record 
under which mode of operation it was operating at all times. An example 
of when two modes of operation must be identified would be a cement 
kiln that routes its kiln off-gas through the raw meal mill to help dry 
the raw meal. When the raw meal mill is not operating (perhaps one 
third of the time), the kiln gas bypasses the raw meal mill. Emissions 
of PM and other HAPs or HAP surrogates may vary substantially depending 
on whether the kiln gas bypasses the raw meal mill.
    When conducting the comprehensive performance test, sources must 
also operate under representative conditions for the following 
parameters to ensure that emissions are representative of normal 
operating conditions: (1) types of organic compounds in the waste 
(e.g., aromatics, aliphatics, nitrogen content, halogen/carbon ratio, 
oxygen/carbon ratio) and volatility of wastes, when demonstrating 
compliance with the D/F emission standard; and (2) cleaning cycle of 
the PM control device (e.g., ESP rapping cycle) when demonstrating 
compliance with the SVM and LVM emission standard when using manual 
stack sampling and the D/F emission standard.
    b. Frequency of Testing. The rule would require that the 
comprehensive performance test be performed periodically because the 
Agency is concerned that long-term wear-and-tear on critical components 
(e.g., firing systems, emission control equipment) could adversely 
affect emissions. Large sources (i.e., those with a stack gas flow rate 
greater than 23,127 acfm) and sources that accept waste from off-site 
would be required to perform comprehensive performance testing every 
three years.
    Small, on-site sources would be required to perform testing every 
five years, unless the Director determines otherwise on a case-specific 
basis. The proposed testing frequency would be less for small, on-site 
sources because of cost-effectiveness concerns. In addition, we note 
that, from the RCRA perspective, small, on-site sources are more 
familiar with the wastes they burn, the waste may be more homogeneous 
and less complex, and they burn smaller volumes of waste. Thus, their 
emissions may not pose the same hazard as emissions from large or 
commercial facilities. We invite comment on this approach.
    The Director may determine, however, that a small, on-site source 
may pose the same potential hazard as a large or off-site source 
because of the factors listed above, compliance history, or other 
reasons. Accordingly, the rule would allow discretion for the Director 
to require a three-year testing frequency for such small, on-site 
sources as warranted.
    c. Agency Oversight. The proposed rule would require the owner or 
operator to submit a ``notification of performance test'' to the 
Administrator 60 days prior to the planned test date. The notification 
must be accompanied by a site-specific test plan for review and 
approval by the Administrator. This is consistent with the general 
provisions for MACT sources provided by Sec. 63.7 (b) and (c). See 
those paragraphs for provisions regarding: (1) Agency approval of the 
test plan; (2) 30-day period for the Agency to approve or disapprove 
the test plan; 171 and (3) notwithstanding Agency approval or 
disapproval, or failure to approve or disapprove, the test plan, the 
owner or operator must comply with the applicable requirements, 
including the

[[Page 17445]]

deadline for submitting the initial and subsequent notifications of 
compliance.
---------------------------------------------------------------------------

    \171\ Generally, Sec. 63.7(c)(3) provides that the source can 
assume the test plan is approved if the Agency does not take action 
within 30 days of receiving the original plan or any supplementary 
information.
---------------------------------------------------------------------------

    In addition, the Agency has the option of observing the performance 
test.
    d. Operating Conditions During Subsequent Tests. Although the rule 
would allow the burning of hazardous waste only under the operating 
limits established during the previous comprehensive performance test 
(to ensure compliance with emission standards not monitored with a 
CEMS), two types of waivers from this requirement would be provided 
during subsequent comprehensive performance tests: (1) an automatic 
waiver to exceed current operating limits up to 5 percent; and (2) a 
waiver that the Director may grant if warranted to allow the source to 
exceed the current operating limits without restriction. The rationale 
and implementation of these waivers is discussed below.
    The rule would provide an automatic waiver because, without the 
waiver, the operating limits would become more and more stringent with 
subsequent comprehensive performance tests. This is because sources 
would be required to operate within the more stringent conditions to 
ensure that they did not exceed a current operating limit. This would 
result in a shrinking operating envelope over time.
    Accordingly, EPA is proposing to allow sources to operate under the 
``same'' operating conditions as the previous comprehensive performance 
test in order to duplicate the current operating limits. It is not 
practicable to require a source to operate under the exact same 
operating conditions as the previous comprehensive performance test, 
however. Therefore, the rule would allow sources to deviate during 
comprehensive performance testing by up to 5 percent from the current 
operating limits provided that the source accept operating limits based 
on the new performance test levels that are the more stringent of the 
current operating limits or levels achieved during the new performance 
test. We invite comment on whether this provision would meet our 
objective of ensuring that the operating envelope does not shrink over 
time as subsequent comprehensive performance tests are conducted. For 
example, an additional approach would be to provide for a site-specific 
waiver of the 5 percent deviation limit to allow deviations from 
current operating limits as warranted to ensure that the operating 
envelope does not shrink.
    The rule also proposes a waiver that the Administrator may grant if 
warranted to allow the source to exceed the current operating limits 
without restriction. This is because the source may want to operate 
under less restrictive limits and believes that it can still comply 
with the emission standards under the less restrictive limits. For 
example, a source may want to burn a waste with higher metal or 
chlorine content, and/or the source may want to install an improved 
emission control device.
    To accommodate such situations, the rule would allow the 
Administrator to grant a site-specific waiver of the operating limits 
if the source provides supporting documentation that it is likely to be 
able to meet the emission standards under less restrictive operating 
limits. The documentation must be submitted prior to or at the time of 
submittal of the notification of performance test, and must include 
empirical data or other data and information to support the request. If 
the waiver request is submitted with the notification of performance 
test (which must be accompanied by the test plan), the Director will 
approve or disapprove the waiver request under the procedures for 
approving or disapproving the test plan.
    e. Testing Schedule and Notification of Compliance. The owner or 
operator must submit to the Administrator a notification of compliance 
under proposed Sec. 63.1211(c) documenting compliance with the emission 
standards and CMS requirements, and identifying applicable operating 
limits. (This provision is similar to Sec. 63.7(g).) The notification 
must be postmarked by the 90th day following the completion of 
performance testing and CMS performance evaluation.
    The initial notification of compliance must be postmarked within 36 
months after the date of publication of the final rule. Subsequent 
notifications must be submitted within 90 days after the completion of 
subsequent performance testing. Subsequent comprehensive performance 
testing must be initiated 36 months for large and off-site sources or 
60 months for small, on-site sources, respectively, after initiation of 
the initial performance test.
    Given the complexity of comprehensive performance testing and to 
allow for unforeseen events, however, the rule would allow the 
subsequent test to be initiated within a range of 30 days before or 
after the 36 or 60-month anniversary. The rule would require that the 
anniversary date remain based on the initial comprehensive performance 
test. This would simplify recordkeeping and preclude a source from 
intentionally scheduling the test toward the end of the 30-day grace 
period and thus effectively obtaining a 37 or 61-month testing 
frequency.
    The rule would give a source the option of performing a 
comprehensive performance test at any time before the 36 or 60-month 
anniversary. A source may want to retrofit or add a new emission 
control device prior to a test anniversary date. To do so, the source 
would be required to conduct a new comprehensive performance test to 
document compliance with emission standards and to establish new 
operating limits. The rule would require the source to follow the same 
procedures for this comprehensive performance test as discussed above 
(e.g., submittal of notification of performance testing and test plan; 
review and approval of test plan). Note that conducting a comprehensive 
performance test prior to the normal anniversary date would establish a 
new anniversary date.
    f. Time Extensions for Subsequent Performance Tests. The rule would 
allow the Administrator to grant up to a 1 year time extension for any 
performance test subsequent to the initial comprehensive performance 
test.172 This would enable the source to consolidate, into one 
test, both the MACT-related performance testing and the RCRA trial burn 
testing, which are both required for issuance and reissuance of RCRA 
operating permits.173 (Trial burn testing requirements are 
discussed below.)
---------------------------------------------------------------------------

    \172\ Note that we discuss in Part Five, Section I (Selection of 
Compliance Dates) of the preamble that the rule would provide up to 
a 1-year time extension to submit the initial notification of 
compliance.
    \173\ In addition, the source may experience a major outage 
whereby the performance test could not be conducted within the 2-
month window around the anniversary date. This time extension 
provision could address this situation as well.
---------------------------------------------------------------------------

    For example, if the comprehensive performance test anniversary were 
a date proximate to the date scheduled for the trial burn, we believe 
it is reasonable to allow the source to conduct only one test to 
satisfy both requirements (i.e., the MACT-related performance test and 
the RCRA trial burn). To address this situation, the rule would allow 
up to a one-year time extension for the performance test.174
---------------------------------------------------------------------------

    \174\ Note that, if the trial burn were scheduled before, rather 
than after, the performance test anniversary date, there would not 
be a problem because the source can conduct a comprehensive 
performance test at any time prior to the anniversary date. If so, 
the anniversary date is simply moved up.
---------------------------------------------------------------------------

    When the trial burn and performance tests are consolidated, the 
anniversary dates for subsequent performance tests would be 
correspondingly adjusted. For example, if the anniversary date for a

[[Page 17446]]

confirmatory performance test for a large or off-site source is January 
1 and the trial burn is scheduled for September 1 of that year, the 
source may adjust the anniversary date of the confirmatory performance 
test to September 1. This would also delay the anniversary date for 
subsequent comprehensive performance tests by 9 months. As noted above, 
under the proposal a maximum of 12 months delay could be granted.
    The procedure for granting or denying a time extension would be the 
same as those for existing Sec. 63.6(i) which allows the Administrator 
to grant MACT sources up to 1 additional year (in addition to the 3 
years beginning with publication of applicable standards (e.g., MACT 
standards for HWCs) in the Federal Register) to comply with the 
standard.175 (These are also the same procedures that would apply 
to a request for a time extension for the initial notification of 
compliance.)
---------------------------------------------------------------------------

    \175\ Note, however, that Sec. 63.6(i) applies to an entirely 
different situation: extension of time for initial compliance with 
the standard whereby performance testing is conducted after the date 
of compliance.
---------------------------------------------------------------------------

    We invite comment on alternative maximum time periods for the 
extension to allow sources to reasonably consolidate performance and 
trial burn testing, and whether the time extension should be automatic 
or require prior approval by the Administrator.
    vi. Failure to Submit a Timely Notification of Compliance. If the 
owner or operator does not submit a notification of compliance by the 
required date, the rule would require the source to immediately stop 
burning hazardous waste (the same manner as applied to BIFs certifying 
compliance under RCRA Sec. 266.103 in 1991). If the source wanted to 
burn hazardous waste in the future, it would be required to comply with 
the standards and permit requirements for new MACT and RCRA sources. 
For example, if the source were operating under RCRA interim status, it 
would need to obtain a RCRA operating permit and meet MACT standards 
for new facilities before hazardous waste burning could resume. 
Moreover, the rule would require the source to obtain written approval 
from the Administrator before hazardous waste burning could resume. 
(For RCRA interim status sources, issuance of a RCRA operating permit 
would constitute such written approval.)
    g. Failure of a Comprehensive Performance Test. When a source 
determines (e.g., based on CEMS recordings, results of analysis of 
samples taken during manual stack sampling, or results of the CMS 
performance evaluation) that it has failed any emission standard during 
the performance test, it would be required to immediately stop burning 
hazardous waste. If, however, a source conducts the comprehensive 
performance test under two or more modes of operation and meets the 
emission standards when operating under one or more modes of operation, 
it would be allowed to continue burning under the modes of operation 
for which it has met the standards.
    For sources that fail one or more emission standards during all 
modes of operation tested, the rule would enable the source to burn 
hazardous waste only for a total of 720 hours and only for the purposes 
of pretesting (i.e., informal testing to determine if it could meet the 
standards operating under modified conditions) or comprehensive 
performance testing under modified conditions.
    Finally, failure to comply with an emission standard after initial 
notification of compliance would be a violation of the rule.
    We note that HWCs are currently subject to virtually these same 
requirements under RCRA rules.
    h. Applicability of Existing Part 63 General Requirements for MACT 
Sources. Part 63 establishes requirements for performance testing in 
Sec. 63.7 and requirements for extension of compliance dates in 
Sec. 63.6(i). Some of these provisions would be directly applicable to 
HWCs, some would be applicable in modified form, some would be 
superseded by today's rule, and others are not applicable.
    The following Sec. 63.7 requirements would be applicable to HWCs:
    (1) Paragraph (a)(1) (Applicability) and (a)(3)
    (2) Paragraphs (b) (Notification of performance test) and (c) 
(Quality Assurance Program), except that all sources would be required 
to submit the test plan for review and approval
    (3) Paragraph (d) (Performance testing facilities)
    (4) Paragraph (e) (Conduct of performance tests), except that 
operating conditions during comprehensive performance testing would be 
as discussed above (i.e., not normal operating conditions), and 
operating conditions during confirmatory performance testing discussed 
below would be under normal conditions as defined in that discussion. 
Also, emissions during startup and shutdown would be included in the 
performance tests, if the sources wishes to have the authority to burn 
hazardous waste during those periods.
    (5) Paragraph (f) (Use of an alternative test method)
    (6) Paragraph (g) (Data analysis, recordkeeping, and reporting), 
except that the test results would have to be reported 90 days after 
completion of the test, rather than 60 days.
    The following Sec. 63.7 requirements would not be applicable to 
HWCs:
    (1) Paragraph (a)(2) (establishing deadlines for performance 
testing) because new HWCs would be required to obtain a RCRA operating 
permit before commencing construction. The RCRA operating permit would 
specify allowable periods of operation and operating conditions prior 
to (and following) performance testing. Existing HWCs would be required 
to submit a notification of compliance within 3-years of the date of 
publication of the final rule in the Federal Register.
    (2) Paragraph (h) (Waiver of performance tests), because the bases 
for the waiver are not relevant to HWCs as follows: (1) the rule would 
allow the Administrator to grant a time extension to submit a 
notification of compliance; and (2) the purpose of periodic testing is 
to determine whether sources are meeting the standards on a continuous 
basis.
2. Confirmatory Performance Testing
    Confirmatory performance testing for D/F would be required mid-way 
between the cycle required for comprehensive performance testing to 
determine if the source is continuing to meet the emission standard. 
The Agency is proposing such testing only for D/F given: (1) the health 
risk posed by D/F; (2) there is no CEMS for D/F; (3) there is no 
feedrate limit of a material that directly and unambiguously relates to 
D/F emissions (as opposed to, for example, metals feedrates, which 
directly relate to metals emissions); and (4) wear and tear on the 
equipment, including any emission control equipment, which over time 
could result in an increase in D/F emissions even though the source 
stays in compliance with applicable operating limits.
    Confirmatory testing differs from comprehensive testing, however, 
in that the source would be required to operate under normal, 
representative conditions during confirmatory testing. This would 
reduce the cost of the test while providing the essential information 
because the source would not have to establish new operating limits 
based on the confirmatory test.
    a. Definition of Normal Operating Conditions. Normal operating 
conditions would be defined as operations during which: (1) the CEMS

[[Page 17447]]

that measure parameters that could relate to D/F emissions--PM, CO, 
HC--are recording emission levels within the range of the average value 
for each CEMS (the sum of all one-minute averages, divided by the 
number of one minute averages) over the previous 12 months to the 
maximum allowed; and (2) each operating limit established to maintain 
compliance with the D/F emission standard (see discussion in Part Five, 
section II.C.1) is held within the range of the average values over the 
previous 12 months and the maximum or minimums, as appropriate, that 
are allowed. The Agency believes it is necessary to define normal 
operating conditions in this manner because, otherwise, sources could 
elect to limit levels of the regulated D/F operating parameters (e.g., 
hazardous waste feedrate, combustion chamber temperature, temperature 
at the inlet to the dry PM control device) to ensure minimum emissions. 
Thus, without specifying what constitutes normal conditions, EPA 
believes the confirmatory test could be meaningless. On the other hand, 
the proposed definition of normal conditions is broad enough to allow 
the source flexibility in operations during the test.
    When conducting the confirmatory performance test for D/F, sources 
must also operate under representative conditions for the following 
parameters to ensure that emissions are representative of normal 
operating conditions: (1) types of organic compounds in the waste 
(e.g., aromatics, aliphatics, nitrogen content, halogen/carbon ratio, 
oxygen/carbon ratio) and volatility of wastes, when demonstrating 
compliance with the D/F emission standard; and (2) cleaning cycle of 
the PM control device (e.g., ESP rapping cycle).
    Finally, when conducting the confirmatory test for D/F, the source 
would also be required to conduct a performance evaluation of the CMS 
that are required to maintain compliance with the D/F emission 
standard.
    b. Frequency of Testing. Large and off-site sources would be 
required to conduct confirmatory performance testing 18 months after 
the previous comprehensive performance test. Small, on-site sources 
would be required to conduct the testing 30 months after the previous 
comprehensive performance test. The same 2-month testing window 
applicable for comprehensive tests would also apply to confirmatory 
tests.
    c. Agency Oversight, Notification of Performance Test, Notification 
of Compliance, Time Extensions, and Failure to Submit a Timely Notice 
of Compliance. The requirements that would apply to comprehensive tests 
would also apply to confirmatory tests.
    d. Failure of a Confirmatory Performance Test. When a source 
determines (e.g., based results of analysis of samples taken during 
manual stack sampling) that it has failed the D/F emission standard, it 
would have violated the rule. The source would be required to 
immediately stop burning hazardous waste. If, however, a source had 
conducted the comprehensive performance test under two or more modes of 
operation and met the D/F emission standards during confirmatory 
testing when operating under one or more modes of operation, it would 
be allowed to continue burning under the modes of operation for which 
it has met the standards.
    For sources that fail one or more emission standard during all 
modes of operation tested, the rule would require the source to modify 
design or operation of the unit and conduct a new comprehensive 
performance test to demonstrate compliance with the D/F emission 
standard and establish new operating limits. Further, prior to 
submitting a notification of compliance based on the new comprehensive 
performance test, the source could burn hazardous waste only for a 
total of 720 hours, and only for purposes of informal pretesting or 
comprehensive performance testing.

B. RCRA Trial Burns

    HWCs are also subject to the existing permit requirements under 
RCRA that are established at 40 CFR Parts 264, 266, and 270. Those 
rules require HWCs (among other things) to conduct a trial burn to 
demonstrate compliance with applicable emission standards. Operating 
conditions are included in the permit to ensure that compliance is 
maintained.
    We are proposing to amend those rules today to refer to the 
proposed MACT requirements. Thus, the existing RCRA emission standards 
and ancillary requirements would be superseded by the proposed MACT 
standards, with one exception: destruction and removal efficiency 
(DRE).
1. The RCRA DRE Requirement Would Be Implemented Under RCRA Authority
    The destruction and removal efficiency (DRE) requirement under the 
RCRA standards would continue to apply to all HWCs. Although the DRE 
requirement, which is statutory for incinerators, RCRA 
Sec. 3004(o)(1)(B), could be proposed as a MACT surrogate parameter to 
minimize organic HAPs by ensuring good combustion, we are not doing so. 
This is because the DRE standard is complex and impracticable to self-
implement.176 Consequently, the Agency would continue to apply the 
DRE standard under RCRA authority alone.
---------------------------------------------------------------------------

    \176\ We note that, for this reason, the Agency chose not to 
require BIFs operating under interim status to comply with the DRE 
standard even though they were subject to all other emission 
standards that would be applicable under a operating permit.
---------------------------------------------------------------------------

2. Coordinating Trial Burns and MACT Performance Tests
    As discussed above, the rule would allow a source to consolidate a 
trial burn test with a comprehensive or confirmatory test if the trial 
burn test were conducted within a year after the anniversary date for 
the MACT performance test.177 If the tests are consolidated, 
however, the unified test must of course satisfy the objectives of both 
tests.
---------------------------------------------------------------------------

    \177\ If the trial burn were scheduled prior to the performance 
test, the source could elect to consolidate the tests and, thus, 
move up the anniversary date for the performance test.
---------------------------------------------------------------------------

    We note that the level of Agency oversight for trial burns is 
substantially greater than the oversight that might be provided for 
MACT performance tests. Accordingly, as current practice, the Agency's 
implementation procedures for trial burns will deviate from those 
proposed for the MACT performance tests. As examples, the Agency will 
require that the test plan be submitted more than 60 days in advance of 
the planned trial burn test, and extensive public participation will be 
provided for review of the test plan, test results, and determination 
of operating limits.

C. Waiver of MACT Performance Testing for HWCs Feeding De Minimis 
Levels of Metals or Chlorine

    Today's rule would provide a waiver of performance testing 
requirements for Hg, SVM, LVM, or HCl/Cl2 for HWCs that feed de 
minimis levels of these metals or chlorine.178. Under the waiver, 
a source would be required to assume that all Hg, SVM, LVM, or chlorine 
fed in each feedstream is emitted from the stack and to document that 
resulting emission concentrations do not exceed the emission standards, 
considering stack gas flow rate. Thus, the source would be required to: 
(1) establish and comply with maximum feedrate limits for total 
feedstreams for Hg, SVM, LVM, or chlorine; and (2) establish and comply 
with, as a minimum stack gas flow rate, the flow rate used to document 
compliance (by calculation

[[Page 17448]]

rather than emissions testing) with the emission standard.
---------------------------------------------------------------------------

    \178\ Note that the term de minimis means simply low 
concentration of metals or chlorine. It does not denote or imply low 
risk.
---------------------------------------------------------------------------

    To accommodate sources that may operate under a wide range of gas 
flow rates, the rule would allow a source to establish different modes 
of operation with corresponding minimum stack gas flow rate limits and 
maximum feedrates for metals or chlorine. If a source uses this 
approach, the operating record must clearly identify which operating 
mode is in effect at all times.
    Sources claiming the waiver would be required to do so in the 
initial notification of performance test and would not be required to 
establish or comply with operating limits for the performance test 
(i.e., Hg, SVM, LVM, or HCl/Cl2) for which the waiver is claimed. 
Sources eligible for a waiver from the Hg standard would not be 
required to install a Hg CEMS.

D. Relative Accuracy Tests for CEMS

    This section describes the testing requirements for CEMS proposed 
today. Note that CEMS for multi-metals, HCl, and Cl2 are proposed 
to be optional. Facilities need not perform tests described below for 
CEMS they elect not to use.
    A relative accuracy test audit (RATA) for Hg and multi-metal CEMS 
would be required every three years (or five years for small on-site 
facilities). RATAs for CO and O2 CEMS would be required 
annually.179 RATAs for Hg and multi-metals involve comparing the 
output of the CEM to the results of manual method tests in order to 
determine the overall accuracy of the CEM and would be conducted in 
conjunction with a comprehensive test. RATAs for CO and O2 would 
be conducted during a comprehensive test or on the anniversary date of 
the previous comprehensive test.
---------------------------------------------------------------------------

    \179\ Note that EPA invites comment on waiving the RATA 
requirements for CO and O2, instead relying on quarterly 
calibration error tests using cylinder gasses.
---------------------------------------------------------------------------

    A relative calibration audit (RCA) for PM CEMS would be required 
every 18 months (30 months for small on-site facilities). These are 
similar to a RATA in that they involve comparing the output of the CEM 
to the results of manual method tests in order to verify the validity 
of the CEM and its calibration, and would be conducted whenever a 
comprehensive or confirmatory test is performed.
    An absolute calibration audit (ACA) is a test which determines the 
calibration error (CE) associated with a CEM. These audits do so by 
challenging the analyzer using gas bottles or solutions of metals or 
particulate with known concentrations of the compound being analyzed. 
ACA's are conducted quarterly for all CEMS except for multi-metals, 
which are conducted annually.
    Calibration drift (CD) and zero drift (ZD) 180 tests are 
conducted daily using cylinder gas bottles, filters, or internal (to 
the CEMS) calibration standards.
---------------------------------------------------------------------------

    \180\ Note that EPA invites comment on whether the ZD 
requirements should be deleted.
---------------------------------------------------------------------------

IV. Selection of Manual Stack Sampling Methods

    This section discusses the manual emission test methods that would 
be required for emission tests and calibration of CEMS and relies 
heavily on the BIF methods currently in Part 266, Appendix IX. EPA 
previously proposed incorporating many of these methods in SW-846, Test 
Methods for Evaluating Solid Wastes (60 FR 37974, July 25, 1995). 
Accordingly, both the BIF and proposed SW-846 numbers are given.
    The emission test method for D/F would be the proposed SW-846 
Method 0023A (60 FR 37974, July 25, 1995). It is identical to the BIF 
Method 23 in Appendix IX of Part 266 except Method 0023A requires that 
collection efficiencies be determined for both the particulate and 
sorbent. BIF Method 23 is the same as the Air Method 23 in Part 60, 
Appendix A. Method 23 determines the efficiency off the sorbent only 
and assumes the same recovery off the particulate as from the sorbent. 
We are also proposing today to make a conforming change to the BIF rule 
to require use of Method 0023A rather than Method 23.
    It is proposed that BIF Method 0012 (SW-846 method 0060) be used as 
the manual method test for Hg. The proposed manual emission test method 
for the SVM and LVM standards is BIF Method 0012 contained in section 
3.1 of Appendix IX, Part 266 (SW-846 method 0060). This method is also 
commonly known as Air Method 29.
    For compliance with the HCl/Cl2 standard, the rule would use 
BIF Methods 0050, 0051, and 9057 contained in section 3.3 of Appendix 
IX, Part 266, as the manual test method (SW-846 would retain the same 
numbering). These methods are commonly known as Air Method 26A, found 
in Appendix A of Part 60.
    Existing Sec. 63.7 describes procedures for allowing the use of 
alternative test methods for MACT sources. This procedure involves 
using Method 301 of Part 60, Appendix A, to validate the proposed 
method. The data from the Method 301 validation is submitted to EPA. 
EPA then decides if the proposed method is acceptable. Absent this 
approval under Sec. 63.7 procedures, alternate methods cannot be used.

V. Notification, Recordkeeping, Reporting, and Operator Certification 
Requirements

    Today's proposed rule would establish several notification, 
recordkeeping, and reporting requirements for HWCs. This section 
discusses the applicability to HWCs of existing requirements in 
Secs. 63.9 and 63.10 and Parts 264, 265, 266, and 270. In addition, we 
discuss in this section new requirements that would apply specifically 
to HWCs. Finally, we discuss whether operator certification 
requirements should be promulgated.

A. Notification Requirements

    HWCs would be required to submit the following notifications:
     Initial notification. The initial notification 
requirements of existing Sec. 63.9(b) would apply. These notifications 
are intended to alert regulatory officials that a source is subject to 
the regulations. Even though all existing HWCs have already notified 
the Administrator of their hazardous waste activities under RCRA 
requirements, and new HWCs must notify the Administrator and obtain an 
operating permit before commencing construction, these RCRA-required 
notifications will not always be received by the same regulatory 
officials implementing the MACT standards. For example, when a state is 
authorized for Title V permitting, various state regulatory 
authorities, including local air boards, could be the implementing 
authority. In contrast, RCRA regulations are implemented by Agency and 
state officials. Accordingly, to ensure that all appropriate regulatory 
officials are apprised that a HWC is subject to the MACT and RCRA 
regulations, we are proposing to retain the initial notification 
requirement under Sec. 63.9(b).
     Notification of performance test and CMS performance 
evaluation. This notification includes the planned test date, 
performance test plan (to demonstrate compliance with emissions), CMS 
performance evaluation plan, and quality assurance plan. It is required 
by existing Sec. 63.9(c), except that all sources must submit their 
test plan and CMS performance evaluation plan for review and approval.
     Notification of compliance. This notification includes 
results of performance test and CMS performance evaluation and 
certification by the owner and operator that the source is in 
compliance with the applicable

[[Page 17449]]

standards. It is similar to that required by existing Sec. 63.9(h) with 
several important differences. Under today's rule, a source must notify 
that it is actually in compliance with all applicable standards, not 
merely identify its status with respect to compliance as allowed by 
Sec. 63.9(h). In addition, paragraphs (h)(2) (D) and (E) requiring the 
source to identify the type and quantity of pollutants emitted and an 
analysis of whether the source is a major or area source are not 
applicable to HWCs. This is because today's proposed rule would apply 
to all HWCs irrespective of whether it meets the definition of a major 
source. Finally, today's rule would require the notification to be 
submitted 90 days after completion of testing, rather than 60 days as 
now required by paragraph (h)(2)(ii).
     Request for extension of time to submit a notification of 
compliance. A notification for a time extension for initial compliance 
is provided by Sec. 63.9(c). Today's rule would require sources to 
submit a notification of compliance after each performance test (both 
comprehensive and confirmatory) and allow requests for time extensions 
to submit those notifications.
     Request for a time extension to consolidate a performance 
test with a trial burn. Today's rule would allow a source to request to 
consolidate a trial burn with a performance test if the trial burn test 
date is no later than 12 months after the performance test anniversary 
date.
    To summarize applicability of existing Sec. 63.9 notification 
requirements and to assist the regulated community in understanding the 
applicable requirements, the following list is provided as guidance:
     Paragraph (a) (Applicability and general information) 
applies.
     Paragraph (b) (Initial notifications) applies as discussed 
above.
     Paragraph (c) (Request for extension of compliance) 
applies for the purposes discussed above.
     Paragraph (d) (Notification that source is subject to 
special compliance requirements) applies.
     Paragraph (e) (Notification of performance test) applies 
as discussed above.
     Paragraph (f) (Notification of opacity and visible 
emission observations) is not applicable because the rule would 
establish a PM emission standard and other compliance/monitoring 
requirements in lieu of opacity and visible emission standards.
     Paragraph (g) (Additional notification requirements for 
sources with CMS) applies.
     Paragraph (h) (Notification of compliance status) applies 
with the caveats discussed above.
     Paragraph (i) (Adjustments to time periods or postmark 
deadlines for submittal and review of required communications) applies.
     Paragraph (j) (Change in information already provided) 
applies. The rule would require the following additional notification 
requirements:
     Small quantity on-site burner exemption. See discussion in 
Part Six, Section II.A.1.
     Pre-trial burn period (shakedown). See discussion in Part 
Six, Section II.F.1.

B. Reporting Requirements

    HWCs would be required to submit the following reports:
     Excessive AWFCO report. See discussion in Part Five, 
Section II.E.1.
     ESV opening report. See discussion in Part Five, Section 
II.E.1.
    For guidance to the regulated community, the applicability of the 
existing reporting requirements under Secs. 63.10(d) (General reporting 
requirements), 63.10(e) (Additional reporting requirements for sources 
with CMS), and 63.10(f) (Waiver of recordkeeping or reporting 
requirements) would be as follows:
     Paragraph (d)(1) applies. This paragraph references the 
reporting requirements in the specific standards for a source category, 
in this case proposed Subpart EEE.
     Paragraph (d)(2) (Reporting results of performance tests) 
applies, except that the report may be submitted up to 90 days after 
completion of the test.
     Paragraph (d)(3) (Reporting results of opacity or visible 
emission observations) does not apply because the rule would not 
regulate opacity or visible emissions.
     Paragraph (d)(4) (Progress reports) applies.
     Paragraph (d)(5) (Periodic startup, shutdown, and 
malfunction reports; and immediate startup, shutdown, and malfunction 
reports) does not apply. Given that HWCs could not burn hazardous waste 
under the proposed rule except in compliance with all applicable 
emission standards, operating limits, and CMS performance 
specifications, the rule would not require a startup, shutdown, and 
malfunction plan as required by Sec. 63.6(e)(3) for other MACT sources. 
There will be no excess hazardous waste emissions during these periods 
(unless the HWC violates the standards) and the Agency does not need 
information about how quickly a HWC is able to correct a malfunction or 
come back into compliance again so that it may resume hazardous waste 
burning.181
---------------------------------------------------------------------------

    \181\ One exception to this is the operation of cement kilns 
when the hazardous waste feed has been cut off and there is no 
hazardous waste remaining in the combustion chamber. In this 
situation, the HWC emission standards, operating limits, and CMS 
performance specifications would not apply. Given that the Agency 
plans to propose MACT standards for cement kilns that do not burn 
hazardous waste, however, a cement kiln that is temporarily not 
subject to today's proposed standards because the waste feed has 
been cutoff (and there is no hazardous waste remaining in the 
combustion chamber) would nonetheless remain (or become) subject to 
any MACT standards the Agency may promulgate.
---------------------------------------------------------------------------

     Paragraph (e)(1) (General) applies.
     Paragraph (e)(2) (Reporting results of CMS performance 
evaluations) applies.
     Paragraph (e)(3) (Excess emissions and CMS performance 
report and summary report) does not apply because HWCs cannot burn 
hazardous waste except in compliance with all applicable standards.
     Paragraph (e)(4) (Reporting continuous opacity monitoring 
system data produced during a performance test) does not apply because 
COMs are not required in this proposal.
     Paragraph (f) (Waiver of recordkeeping or reporting 
requirements) would not apply because the bases for considering the 
waiver are not relevant to HWCs as follows: (1) Recordkeeping and 
reporting should not be waived because ``the source is achieving the 
relevant standards'' because recordkeeping and reporting would be the 
primary means of compliance assurance for the HWC rules; (2) 
recordkeeping and reporting should not be waived during a time 
extension because the requirements would not apply until a HWC 
submitted the initial notification of compliance irrespective of 
whether a time extension were granted; and (3) recordkeeping and 
reporting should not be waived if a time extension is granted for a 
subsequent notification of compliance (because the source will be 
burning hazardous waste under the standards).

C. Recordkeeping Requirements

    Existing Sec. 63.10(b)(1) requires MACT sources to keep the records 
discussed below for at least five years from the date of each 
occurrence, measurement, maintenance, corrective action, report, or 
record. At a minimum, the most recent two years of data must be 
retained off-site. The remaining three years of data may be retained on 
site. Such files may be maintained on: microfilm, a computer, computer 
floppy disks, optical disk, magnetic tape, or microfiche.

[[Page 17450]]

1. Information Required in the Operating Record
    The rule would require HWCs to record the following in the 
operating record:
     Comprehensive test results used to determine operating 
limits. See discussion in Part Five, Section II.B.
     All operating parameter limits established. See discussion 
in Part Five, Section II.C.
     Operating data which substantiates compliance, including 
minute-by-minute operating parameter data, including feedstream; and 
minute-by-minute CEM data. See discussion in Part Five, Section II.B.
     Documentation for performance test waiver. See discussion 
in Part Five, Section III.C.
     Description of and operating data substantiating 
compliance with provisions to limit combustion fugitive emissions. See 
discussion in Part Five, Section II.D.
     For each occurrence of an exceedance of a CEM or operating 
parameter limit, including what operating parameter of CEM limit was 
violated: the cause of the violation, and what corrective action was 
taken to ensure the violation will be prevented in the future. See 
discussion in Part Five, Section II.E.1.
     For each ESV opening: documentation that the ESV opened, 
the reason for the opening, and corrective measures taken to minimize 
the frequency of openings. See discussion Part Five, Section II.E.2.
     ESV operating plan. See discussion Part Five, Section 
II.E.2.
     CEM quality assurance document, including: definition of 
compliance with the calibration and zero drift specifications, and how 
relative accuracy and absolute calibration audits will be performed. 
See discussion Part Five, Section II.F.1.
     Feedstream Analysis Plan, including: the parameters for 
which each feedstream will be analyzed to ensure compliance; whether 
the owner or operator will obtain the analyses by performing sampling 
and analysis or by other methods; how the analysis will be used to 
document compliance; the test methods used; the sampling method used; 
and the frequency of testing. See discussion in Part Five, Section 
II.F.2.
     Other Continuous Monitoring Systems (CMS), including: 
manufacturer's written specifications for installation, operation, and 
calibration of a CMS; and technical specifications of CMS, such as 
spans and percent error. See discussion in Part Five, Section II.F.3.
    In addition, HWCs would be required to develop and keep in the 
operating record a feedstream management plan that enables the source 
to maintain compliance with CEM-monitored emission standards. Although 
a facility using a CEM for compliance would not be required to comply 
with feedrate limits, the owner and operator would be required to 
develop a feedstream management plan (and include it in the operating 
record) that will enable the source to know the feedrate in all 
feedstreams of Hg (as well as other metals and chlorine if the source 
elects to use a CEM for compliance monitoring) at all times to minimize 
automatic waste feed cutoffs and exceedances of the emission standard. 
Knowledge of Hg (and other metals and chlorine) concentration of 
feedstreams can come from the waste generator, supplier, or other 
information, and need not be obtained by sampling and analysis by the 
burner. If the source experiences frequent AWFCOs or exceedances, 
enforcement officials will determine if a feedstream management plan is 
in place. If the plan is determined to be inadequate, the Director may 
require that it be upgraded, taking into account whether a good faith 
effort has been made to develop a plan, even if the plan is determined 
to be inadequate.
    Note that RCRA/HSWA already requires the facility owner to certify 
no less than annually, that the facility has a waste minimization 
program in place, and the certification must be maintained in the 
facility's operating record. The facility owner is encouraged to 
coordinate the development of the feedstream analysis plan and the 
feedstream management plan with the facility's waste minimization 
program. EPA published Interim Final ``Guidance to Hazardous Waste 
Generators on the Elements of a Waste Minimization Program in Place,'' 
(1993) and the ``Pollution Prevention Facility Planning Guide'' (1993), 
which provide information to facility owners on how to prepare analyses 
of waste streams and options for reducing wastestreams using 
alternative pollution prevention/waste minimization measures. 
Information on these documents can be requested by calling the RCRA 
hotline at 1-800-424-9346.
    Many states provide free pollution prevention/waste minimization 
technical assistance that may aid facilities in the development of 
pollution prevention/waste minimization plans. At least 20 states have 
requirements for certain facilities to prepare pollution prevention/
waste minimization plans. As noted elsewhere in today's rule, 
facilities can get further information on available technical 
assistance by contacting the National Pollution Prevention Roundtable 
in Washington, D.C. at (202) 466-7272, or from Enviro$ense, an 
electronic library of information on pollution prevention, technical 
assistance, and environmental compliance, that can be accessed by 
contacting a system operator at (703) 908-2007, via modem at (703) 908-
2092, or on the Internet at http://wastenot.inel.gov/enviro-sense.
2. Applicability of Sec. 63.10 Recordkeeping Requirements
    The applicability of the existing recordkeeping requirements of 
Sec. 63.10 would be as follows:
     Paragraph (a) (Applicability and general information) 
applies, except for (a)(2) that exempts sources that are operating 
under a compliance extension. This is because sources that receive a 
time extension to submit the initial notification of compliance would 
not be subject to any of the proposed standards. Further, sources that 
receive an extension for a subsequent notification of compliance need 
to comply with recordkeeping and reporting requirements to provide 
compliance assurance given that they are burning hazardous waste during 
the extension.
     Paragraph (b) (General recordkeeping requirements) 
applies, except for (b)(2) (iv)-(vi) that pertain to actions during 
malfunctions, and (b)(3) regarding recordkeeping for applicability 
determinations.
     Paragraph (c) (Additional recordkeeping requirements for 
sources with CMS) would apply, except for (c)(6)-(8), (c)(13), and 
(c)(15) that pertain to malfunctions.
3. New Recordkeeping Requirements
    The rule will also require recordkeeping requirements for the 
following:
     Comparable fuels. Sampling and analysis plan, including 
revisions; and certifications from burners. Under Sec. 261.4 records 
will be kept for as long as the generator manages a comparable fuel, 
plus five years. See discussion in Part 6, Section I.E.6.
     Comparable fuels. Results of sampling and analysis; and 
records of off-site shipments for five years. See discussion in Part 6, 
Section II.E.6.
     Small quantity on-site burner exemption. Under 
Sec. 266.108, records will be kept for 3 years. See discussion in Part 
Six, Section II.D.
     Regulation of residues. Under Sec. 266.112, records will 
be kept until

[[Page 17451]]

closure. See discussion in Part Six, Section II.D.

D. Operator Certification

    The Agency notes that section 129 of the Clean Air Act requires EPA 
to develop and promulgate a model program for the training and 
certification of municipal waste combustor (MWC) and medical waste 
combustor (MWI) operators. Accordingly, the Agency has promulgated 
operator certification and training requirements for MWCs and has 
proposed requirements for MWIs. The Agency is today requesting comment 
on whether similar requirements are necessary and appropriate for 
operators of HWCs.
    The MWC and MWI requirements call for (in part) full operator 
certification of all shift supervisors and chief facility operators by 
the American Society of Mechanical Engineers (ASME) or a State 
certification program. In addition, a least one of the following 
persons is required to be on duty at all times during which the unit is 
combusting waste: a fully certified chief facility operator; a fully 
certified shift supervisor; or a provisionally certified control room 
operator.
    We note that the ASME has recently established a Standard for the 
Qualification and Certification of Hazardous Waste Incinerator 
Operators (ASME QHO-1-1994, January 31, 1995). We request comment on 
whether: (1) operator certification requirements are necessary for 
HWCs; and (2) the ASME standard, or an equivalent State certification 
program) is appropriate and sufficient
    The ASME standard has been developed specifically for hazardous 
waste incinerators. We are not aware of an equivalent standard for 
operators of cement kilns and lightweight aggregate kilns that burn 
hazardous waste. We note, however, that the Cement Kiln Recycling 
Coalition has stated that it is committed to the development of an 
operating training and certification program for its member 
facilities.182 We invite comment and information from owners and 
operators of waste-burning kilns regarding the need for a certification 
standard and the status of development of a standard for such 
combustors.
---------------------------------------------------------------------------

    \182\ Letter from Craig Campbell, CKRC, to Ronald Bastian, 
Chairman, ASME QHO, dated January 5, 1994.
---------------------------------------------------------------------------

VI. Permit Requirements

    The rulemaking approach in today's proposal, to promulgate final 
standards under joint RCRA/CAA authority, raises some challenging 
implementation questions. In this section, permitting strategies are 
discussed. EPA requests comment on how these strategies can be further 
simplified while retaining basic environmental protection goals.

A. Coordination of RCRA and CAA Permitting Processes

    The rulemaking approach chosen for today's proposal is to 
promulgate the final standards for hazardous waste combustors under 
joint RCRA/CAA authority. However, the standards will only appear under 
40 CFR Part 63 (Clean Air Act section). The RCRA regulations in 40 CFR 
Parts 264 and 266 will make reference to these Part 63 standards, 
thereby incorporating them as RCRA standards as well. Thus, legally, 
the new standards will be part of both the RCRA and CAA regulations and 
both regulatory programs (RCRA & CAA) will have an obligation to 
address these standards in permits issued under their authority.
    Although the Agency believes that a single permit would be ideal to 
implement these two programs, today's proposed approach does not always 
eliminate the need for two separate permits. However, it does provide a 
variety of options for State implementation. By using both the CAA and 
RCRA authorities, today's approach provides maximum flexibility for 
permitting authorities at the Regional, State, and/or local levels to 
coordinate the issuance of permits and enforcement activities in the 
way which most effectively addresses their particular situation.
    Currently, combustion facilities are required to obtain two 
permits; a RCRA permit and a CAA permit. Although it is EPA's long term 
goal is to have one permit that would address both RCRA and CAA 
requirements, it is difficult because (1) different pieces of the rule 
rely on different authorities, and (2) significant coordination is 
needed between Regional, State, and local authorities. After careful 
consideration, EPA's goal in today's proposal is to coordinate as much 
as possible between the two permitting programs to avoid duplication of 
effort, inconsistent requirements, and redundant procedures.
    EPA explored the possibility of requiring combustion facilities to 
have only one EPA permit issued under either RCRA authority or CAA 
authority. Promulgating these standards in the CAA regulations and 
requiring only a CAA permit looked promising because RCRA allows EPA to 
defer RCRA regulation to other authorities administered by EPA, if RCRA 
core values are covered by the other federal requirements (RCRA Section 
1006(b)(1)), in this case, the CAA. However, EPA believes that several 
RCRA core requirements (e.g., corrective action, omnibus conditions, 
DRE, etc.) cannot be addressed in a CAA permit, since the CAA does not 
provide the legal authority to address them.
    Promulgating these requirements under RCRA authority and issuing 
only a RCRA permit is not possible because the CAA does not allow 
permits for major sources to be waived. As previously discussed, all 
facilities covered by this rulemaking will be considered major sources. 
Also, CAA specific concerns (e.g., acid rain, criteria pollutants, 
etc.) would not be addressed in a RCRA permit.
    EPA considered placing the revised air emission standards in the 
CAA regulations and including a RCRA permit-by-rule provision that 
would defer to the CAA permit. Under this option, the CAA regulations 
would contain the air emission requirements and the CAA permit would 
contain the emission standards. In addition, a separate RCRA permit 
would address RCRA-specific concerns (e.g., corrective action, omnibus 
conditions, DRE, storage, etc.). This approach would avoid duplicating 
air emission requirements in both permits. EPA is not proposing 
regulatory language that would require this approach because there is 
concern that it might limit the permitting flexibility of the 
implementing agencies by specifying which program would be required to 
address air emissions. Some states have expressed concerns about this 
approach. Many states--for example, those that regulate air emission 
standards under their hazardous waste program--may find it difficult to 
implement this option; also, some states were concerned about the 
ability of local permitting programs being solely responsible for the 
air emissions permitting for these facilities. On the other hand, the 
flexibility EPA is suggesting in today's proposal would not preclude 
states from using this permitting approach.
    More broadly, EPA has not specified any one permitting approach in 
today's proposal. The flexibility the Agency is proposing would allow 
states to decide which permitting approach to take. The important 
things are that all substantive requirements are met and that a timely 
and full opportunity for public involvement is provided during the 
permitting process.
    EPA has identified a range of possible permitting scenarios under 
today's proposed approach. Some examples of

[[Page 17452]]

coordinated efforts between the RCRA and CAA programs include: (1) 
issuing a single permit using both (or either) RCRA and CAA authority, 
and (2) issuing two separate permits with close coordination between 
the two programs.
    In the first example, the two permitting programs would work 
together to issue one permit that meets all the requirements of both 
programs. This joint permit would include CAA-specific items (e.g., 
acid rain, criteria pollutants, etc.), RCRA-specific items (e.g., 
corrective action, omnibus conditions, DRE, etc.), and items common to 
both programs (e.g., air emission standards, etc.). The permit would be 
issued under joint authority and signed by the Director(s) of both 
programs. This scenario is likely to be most appropriate where a State 
has authority for both programs and the two programs have experience 
working together. This approach could also be implemented by using the 
CAA in combination with the RCRA permit-by-rule provision as discussed 
above.
    In the second example, the two permitting programs (one responsible 
for RCRA, and one responsible for CAA) would coordinate their 
permitting efforts. Each program would issue a permit. The requirements 
common to both programs (e.g., stack emission standards, etc.) would be 
included in one permit and the other permit would incorporate the 
common requirements by reference. This approach would avoid duplicative 
and conflicting requirements. In this example, each permit would go 
through the applicable procedures for issuance. To coordinate permit 
issuance, all public participation requirements (notices, comments, 
hearings, etc.) could be combined. Under this approach permits would be 
subject to applicable appeal procedures and enforcement provisions 
under each program; however, EPA would not expect to enforce under both 
permits. The appropriate enforcement response will be determined on a 
case-by-case basis. We invite comment on this point in particular.
    EPA will work with the States to identify issues relating to 
streamlining the permitting programs and to develop any needed guidance 
materials or model processes. Additionally, EPA will continue to pursue 
a mechanism to issue one permit that would address both RCRA and CAA 
requirements.
    An Agency-wide initiative led by the Permits Improvement Team (PIT) 
has recommended ways to improve permitting activities for all 
environmental programs. Under this initiative EPA continues to seek the 
best ways to permit facilities throughout its various media programs. 
The approach in today's proposal is consistent with the current 
direction of the PIT, which suggests avoiding duplication of effort by 
incorporating the air emission standards into one permitting program. 
EPA is committed to harmonizing these two permitting processes as much 
as possible for the implementation of today's proposal.

B. Permit Application Requirements

    EPA reviewed information required for permit applications under 
both the CAA (Sec. 70.5) and RCRA (Part 270) to identify any 
duplication that could be eliminated and to determine whether any CAA 
or RCRA permit application requirements for hazardous waste combustors 
could be combined. Historically, determinations for permit approval for 
facilities regulated under the CAA generally focused solely on the 
efficiency of the air pollution control device (APCD). Conversely, the 
basis for permit approval under RCRA has traditionally been more 
specific and related to details of the combustion unit and process (for 
example, design characteristics of the unit, variability of the waste 
burned, information on the type of waste to determine the effect it may 
have on the quality of the operation of the unit over time, etc.). 
Specific information requirements are listed in Secs. 270.15-270.26 
(see specific technical information requirements in Sec. 270.19 for 
incinerators and Sec. 270.22 for BIFs). For these reasons, EPA has 
concluded that the current Part B information requirements and the 
information requirements in the CAA regulations are not duplicative and 
is proposing that both be retained under the existing regulations to 
assure that all RCRA and CAA concerns are addressed.
    Although some of the general information required under 
Sec. 270.13, Contents of Part A of the RCRA permit application, is also 
requested in Sec. 70.5 of the CAA permit application requirements, EPA 
believes that because this information is so minimal, it would not be a 
burden for the applicant to duplicate it on two separate applications. 
Section 270.13 requires further information under the Part A, such as a 
scale drawing of the facility showing the location of all past, 
present, and future TSD areas, specifications of the hazardous waste 
listed or designated under 40 CFR Part 261 to be handled at the 
facility and a list of all permits or construction approvals received 
or applied for under other programs, to list a few. In addition, 
standards relating to the overall operation of the facility are listed 
under Part B (Sec. 270.14). These standards include, but are not 
limited to, chemical and physical analyses of the hazardous waste and 
hazardous debris to be handled at the facility, description of the 
security procedures, contingency plans, closure and post-closure plans 
(including cost estimates) and a description of the continuing training 
programs. Such standards are not required in the application for a CAA 
permit. EPA has therefore concluded that it would be reasonable to keep 
the application requirements where they now exist and cross-reference 
them where appropriate.

C. Clarifications on Definitions and Permit Process Issues

    Because of the incorporation of the technical standards into both 
the RCRA and CAA regulations, as described previously, both RCRA and 
CAA permitting procedures are applicable. For issues such as the 
meaning of the term ``construction'', there could be confusion since 
the definitions and interpretations under one Act differ from those 
under the other. Our intent is not to reconcile these issues on a 
national basis but to continue to let both apply. As in the past, 
sources regulated under both Acts will need to coordinate with both 
RCRA and CAA permitting authorities to see how these procedures apply 
to them. We note in passing that this approach means that the most 
restrictive limitations or processes will generally govern.
    The Agency requests comment on whether these issues should be 
addressed at the national level. EPA's current preference is not to do 
so, but to leave flexibility for the states and EPA Regions to address 
these issues.
1. Prior Approval
    RCRA and CAA are similar in that both require EPA approval before 
construction or reconstruction of a facility (generally) (Sections 
61.07, 63.5, 270.10(f)). Both programs use hypothetical emissions data 
to make the construction approval decision. If a facility is existing 
before the effective date of the final regulation, both RCRA and CAA 
require notification of operation but do not require approval of the 
construction that has already occurred (Sections 60.7, 
266.103(a)(1)(ii)). (Modification of a permitted facility also requires 
prior approval.)
2. 50 Percent Benchmark
    RCRA and CAA both classify a modification of a facility that costs 
more than 50 percent of the replacement cost of the facility as 
``reconstruction''. However, the significance of this term is different 
under the two statutes. Under

[[Page 17453]]

RCRA, the issue of reconstruction is relevant to interim status 
facilities. An interim status facility planning modifications which 
constitute reconstruction must receive a RCRA permit prior to 
construction of the modifications and operation (Sec. 270.72(b)). Under 
the CAA, reconstruction subjects the facility to standards applicable 
to new facilities (Secs. 60.15, 60.488, and 63.5).
3. Facility Definition
    RCRA and CAA define ``facility'' differently. This definition has 
bearing in determining the value of the facility with respect to the 50 
percent rule on modifications just discussed. CAA defines facility as 
the entire industrial process at the site (profit making productive 
process and pollution control devices), while RCRA for purposes of 
reconstruction refers to a ``comparable entirely new hazardous waste 
facility'' (Section 270.72) excluding other industrial processes at the 
site from consideration in the cost of the existing facility. For a 
site where the only activities are RCRA hazardous waste activities, the 
two definitions are identical. However, sites with non-RCRA industrial 
activities will have differing cost figures for each rule. Therefore, 
the two programs have differing determinations of how much 
reconstruction can occur before the 50 percent benchmark is exceeded. 
However, EPA believes this difference should not constitute a problem, 
since the reconstruction determination has different applications under 
each Act. The RCRA definition should be used for the RCRA application 
to changes during interim status, and the CAA definition should be used 
when determining applicability of new versus existing MACT standards.
4. No New Eligibility for Interim Status
    This joint CAA/RCRA proposed rulemaking revises emission standards 
for incinerators and BIFs and hence amends the original incinerator and 
industrial furnace rules that were finalized in 1981 and 1991, 
respectively. Because these rules established the date on which 
incinerators and BIFs were first subject to a permit requirement, the 
effective dates of those rules created the only opportunity for interim 
status eligibility. Sec. 270.10(e)(1)(A)(ii). The interim status 
windows that occurred in 1981 and 1991 thus will not and legally cannot 
be modified by this rule. Of course, facilities currently burning 
wastes that become newly listed under other, future rules would still 
be able under existing law to qualify for interim status 
(Sec. 270.42(g)).
    To avoid the possibility that readers of Part 63 might be unaware 
of their obligations under RCRA, EPA has inserted a note into Section 
written Section 63.1206 to alert them to this point. This note states: 
``an owner or operator wishing to commence construction of a HWI or 
hazardous waste-burning equipment for a cement kiln or lightweight 
aggregate kiln must first obtain some type of RCRA authorization, 
whether it be a RCRA permit, a modification to an existing RCRA permit, 
or a change under already existing interim status. Please see 40 CFR 
Part 270.''
5. What Constitutes Construction Requiring Approval
    RCRA and CAA both have restrictions requiring approval prior to 
construction. The definition of construction under the RCRA regulations 
and associated interpretations differ from the CAA approach to defining 
construction (case-specific call, see Sections 60.5, 61.06) Facilities 
need to comply with both and should be consulting with applicable 
permitting authorities to assure appropriate site-specific 
interpretations. We believe the RCRA construction definition is 
generally broader (more restrictive) and thus will govern in most 
cases. The Agency believes retaining the two differing definitions will 
not cause problems since they are already being applied concurrently. 
Also, the Agency feels that creating a third construction definition 
for this small subset of the RCRA and CAA facilities would create more 
confusion than it would eliminate.

D. Pollution Prevention/Waste Minimization Options

    EPA believes pollution prevention/waste minimization measures may 
provide facilities additional flexibility in meeting MACT standards. 
Pollution prevention/waste minimization measures have been used by many 
companies to modify processes and install new or improved technologies 
which reduce or eliminate the volume and/or toxicity of hazardous 
wastes generation that would otherwise enter combustion unit 
feedstreams, or be treated or disposed of in some other fashion. EPA is 
soliciting comment on two pollution prevention/waste minimization 
options for reducing or eliminating hazardous constituents that enter 
on-site as well as commercial combustor feedstreams, and that can be 
considered in the definitions of changes in facility operating 
parameters and/or new or improved control technologies for meeting MACT 
standards.
    The first option would require all facilities to provide adequate 
information on alternative pollution prevention/waste minimization 
measures that reduce hazardous constituents entering the feedstream, 
particularly the most persistent, bioaccumulative, and toxic 
constituents, in all permit applications. EPA believes this approach is 
consistent with the national policies of the Pollution Prevention Act 
of 1990, CAA, RCRA, and over 20 states who encourage or require 
pollution prevention plans. Facilities are encouraged to reference 
existing EPA documents, such as the Interim Final ``Guidance to 
Hazardous Waste Generators on the Elements of a Waste Minimization 
Program in Place,'' (May 1993), which provides a guide for developing 
pollution prevention/waste minimization programs. Facilities are also 
encouraged to reference EPA's ``Pollution Prevention Facility Planning 
Guide'' (May 1992), ``An Introduction to Environmental Accounting As A 
Business Management Tool'' (June 1995), and ``Setting Priorities for 
Minimization of Combusted Hazardous Waste'' (November 1995), and to 
contact the National Pollution Prevention Roundtable, and state 
pollution prevention technical assistance programs for additional 
pollution prevention resources. These documents were published as aides 
to facility owners in preparing analyses of pollution prevention/waste 
minimization measures. EPA believes this approach provides maximum 
flexibility to facilities for identifying controls through the 
application of processes, or systems (including pollution prevention/
waste minimization measures) for reducing emissions.\183\
---------------------------------------------------------------------------

    \183\ Under the Clean Air Act Section 112(d)(2), MACT standards 
include, among other things, process changes, substitution of 
materials or other modifications.
---------------------------------------------------------------------------

    EPA believes in many cases, facilities may already be required or 
encouraged to prepare this information in the more than 20 States which 
have pollution prevention facility planning requirements already in 
place. EPA believes this approach will promote consistency in States 
which are requiring facilities to develop pollution prevention/waste 
minimization plans as a basis for developing multi-media permits. This 
approach will enhance, without duplicating, the requirements in this 
proposal for facilities to prepare a feedstream analysis plan and a 
feedstream management plan. In cases where this information has been 
already developed by the facility in accord with State requirements 
within 18 months prior to the date of application, no

[[Page 17454]]

additional pollution prevention/waste minimization information will be 
required as part of the permit application.
    In the second option, EPA proposes to give EPA Regions and States 
discretion to make case by case determinations regarding whether a 
facility must provide adequate information for reducing measures, 
including pollution prevention/waste minimization measures, that will 
minimize hazardous constituents entering the feedstream. EPA believes 
this determination should be made based on the facility's ability to 
verify that they have a waste minimization program in place as required 
under RCRA, the extent to which the facility has reported pollution 
prevention information in annual Toxic Release Inventory reports (for 
facilities subject to TRI reporting requirements), and the extent to 
which information has already been prepared under existing state 
pollution prevention planning requirements, or in conjunction with 
State or local pollution prevention technical assistance programs.
    EPA believes this option provides the regulated community and 
States broad flexibility to integrate existing pollution prevention/
waste minimization programs into the objectives of this rulemaking. 
States, universities and local governments operate over 200 technical 
assistance programs that work cooperatively with companies to identify 
waste minimization options to reduce waste generation and management. 
Some states combine this approach with compliance assistance, and a few 
have in place enforceable waste minimization requirements ranging from 
mandatory waste minimization plans to incorporating waste minimization 
opportunities into permitting, inspection and/or enforcement 
activities. As noted elsewhere, facilities can contact the National 
Pollution Prevention Roundtable in Washington, D.C. at (202) 466-7272 
for further information on technical assistance opportunities, or 
Enviro$ense, an electronic library of information on pollution 
prevention, technical assistance, and environmental compliance. 
Enviro$ense can be accessed by contacting a system operator at (703) 
908-2007, via modem at (703) 908-2092, or on the Internet at http://
wastenot.inel.gov/enviro-sense.

E. Permit Modifications Necessary To Come Into Compliance With MACT 
Standards

    This Notice of Proposed Rulemaking would require facilities to come 
into compliance with a number of new MACT emission standards within 
three years following final promulgation of this rule. Some facilities 
would need to perform facility modifications to come into compliance 
with the MACT standards through changing operating parameters or adding 
new or improved control technology(ies) to reduce emissions. For 
example, incinerators that currently operate above the MACT PM 
emissions standards would potentially need to add or modify 
electrostatic precipitators (ESP) or baghouses to reduce emissions. 
Incinerators with a need to reduce dioxin emissions may need to look 
into establishing better controls on temperature or the use of carbon 
injection. LWAKs with potential exceedances in acid gas emissions may 
need to add control technology such as wet scrubbers. These facility 
changes may need to be added to a facility's existing RCRA permit 
through a permit modification. The facility, in this case, would need 
to apply for and receive approval for a permit modification (unless it 
is a class 1 modification) before commencing with its proposed 
change(s).
    This rule is being proposed under both RCRA and the Clean Air Act 
Amendments. With regard to coming into compliance with these proposed 
standards, the Clean Air Act creates a mandatory compliance deadline of 
three years for facilities subject to these regulations (with a one 
year allowance for an extension granted on a case-by-case basis). The 
MACT standards are self-implementing in that they take effect in the 
absence of a CAA permit. As mentioned earlier in this notice, the 
Agency is also taking comment on whether it would be appropriate to 
move up the compliance date of this rulemaking from the proposed three 
year timeframe following promulgation to a timeframe closer to many 
RCRA-based regulations, that of six months to a year. The Agency is 
taking comment, as well, on any other timeframes which can be 
considered both technically and legally feasible.
    However, these sources also hold RCRA permits (or operate under 
interim status) which likely would have to be modified as a result of 
efforts to comply with the MACT emission standards. With respect to 
facilities with RCRA permits, EPA is concerned that these facilities 
could submit a high number of Class 2 or Class 3 permit modification 
requests within the three year window before MACT compliance begins. 
This large influx could potentially lead to difficulties in timely 
processing of modification requests by EPA or State agencies. As a 
result, facilities potentially would not have conformed their RCRA 
permits to reflect the changes needed to meet the MACT standards. The 
Agency anticipates that many of the permit modification requests will 
contain either identical or similar proposed changes, given the 
similarities in incinerator, cement kiln, and LWAK design and 
operation. Given the large number and the potential for duplication of 
modification requests, and the desire to achieve timely emissions 
reductions, the Agency is considering options that will streamline the 
RCRA permit modification process to ensure that necessary modifications 
are made expeditiously, particularly in light of the fact that these 
standards could potentially become effective in a shorter period of 
time, depending on comments received from the public on this proposed 
rulemaking.
    In today's proposal, we are seeking comment on five main options 
(referred to as modification options 1-5) which propose various 
mechanisms to expeditiously authorize changes made to comply with this 
rule. Also, the Agency is seeking comment on three approaches to 
address whether EPA or a state would process necessary permit 
modifications (referred to as implementation approaches 1-3) where a 
state is authorized to issue RCRA incineration and BIF permits but is 
not authorized to implement the new combustion rule. This situation 
should arise only where a state does not adopt the necessary provisions 
of the new rule within the time required by 40 CFR Part 271.21. EPA 
strongly urges states to adopt this rule, once finalized, expeditiously 
in order to streamline the processing of necessary modifications.
    This notice seeks comment on which modification option or 
combination of modification options would be the most viable. The 
Agency is also taking comment on any combination of the above 
implementation approaches and options if an intermediate option and 
implementation approach combination seems more appropriate. Under the 
current RCRA permit modification scheme, a permitted facility would 
refer to Appendix I of 40 CFR 270.42 to determine if its proposed 
modification is classified in the modifications table. A modification 
may rank as Class 1, 2, or 3 (see 53 FR 37912 (Sept. 28, 1988)). A 
higher modification class signifies an increased significance of the 
facility change which is accompanied with a commensurate increase in 
the level of public participation. Facilities can proceed with most 
Class 1 changes without notifying the Agency, though some Class 1 
modifications require prior Agency approval. Owners and operators must, 
in all cases, notify the public and

[[Page 17455]]

the authorized Agency once they have made a Class 1 modification. For 
cause, the Agency may reject any Class 1 modification.
    Class 2 modifications provide for considerably more participation 
by both the facility and the public including an informational meeting 
between the owner and the public regarding the owner's request prior to 
the Agency decision. Class 3 modifications substantially alter the 
facility or its operations. As a result, they require the most Agency 
review and are subject to more public participation requirements than a 
Class 1 or 2 modification, including the full part 124 procedures for 
processing draft permit decisions.
1. Proposed Options Regarding Modifications
    To provide a procedural framework that allows these facilities to 
make the necessary changes in RCRA permits, the Agency proposes to 
amend the interim status and permit modification requirements.
    a. Modifications During Interim Status. Interim status facilities 
can make certain facility alterations with fewer procedural hurdles 
than apply to permitted facilities. However, many changes do require 
Agency approval. In addition, interim status facilities must adhere to 
all reconstruction requirements found in 40 CFR Part 270.72 and must 
revise their Part A permit applications. To ensure that facilities 
making changes to come into compliance with today's proposed MACT 
standards are not constrained by the reconstruction limits under 
Sec. 270.72, the Agency is proposing to add a new sub-section as (b)(8) 
that would exempt those facilities from the reconstruction limitation. 
The Agency does not expect that the costs to come into compliance would 
exceed the 50 percent limit for reconstruction--defined as 50 percent 
of the cost of a new, comparable hazardous waste management facility. 
However, since the limit is cumulative for all changes at the interim 
status facility, there could be cases where this provision could pose 
problems (e.g., where the facility had invested in a number of prior 
changes).
    b. Permit Modifications. For permitted facilities, EPA's goal is to 
implement a procedural system which is as streamlined as possible, but 
still allows for a satisfactory level of public input. The Agency 
believes that a streamlined process can result in earlier achievement 
of the more stringent MACT requirements by facilities, leading to more 
environmentally protective operations. The approach is consistent with 
general efforts within the Agency to improve environmental permits by 
focusing on performance standards, rather than on a detailed review of 
the technology requirements.
    The Agency's first, most streamlined option is that the facility 
would be given overall self-implementing authority (as it has under the 
CAA) to perform all necessary facility modifications to comply with the 
new standards without having to obtain a permit modification from 
either the state or the Agency. This option provides the facility with 
the greatest latitude and authority since it would allow the facility 
the opportunity to make changes to its waste management process and to 
operate under conditions which are different than those which are 
specified in either the HSWA or base portion of its existing RCRA 
permit. Under this option, there would be no immediate need for the 
facility to request a permit modification to incorporate these 
operating changes into the existing permit. These changes, provided 
they enable the facility to meet the new CAA standards, would be 
incorporated into the permit at some later date (e.g. during the permit 
renewal process). It should be noted that this option does not provide 
for public participation at the time the facility is altering its 
process to comply with the new standards. Public involvement would 
instead occur as part of a later permit action, such as permit 
reissuance. It would also not provide for State or Federal agency 
oversight prior to design or operating changes. This option is based on 
the theory that, so long as the facility is meeting the applicable 
performance standards, there may be no need to review how it comes into 
compliance.
    The Agency's second modification option would consider all 
modification requests due to the MACT standards to be Class 1 
modifications requiring no prior approval. The basis for this option 
would be to ensure that facilities are capable of meeting the new 
standards within the three year compliance window because like Option 
1, it relieves the facility of possible delays associated with 
obtaining prior approval for modifications needed to come into 
compliance. It also puts substantial compliance responsibility on the 
facility to make the correct changes within the allotted time.
    The Agency's third option, for which rule language has been 
proposed, would revise Appendix I of 40 CFR 270.42 to designate as 
Class 1 modifications with prior Agency approval all initial requests 
for permit modifications made by facilities in order to comply with 
today's MACT standards. Appendix I of 40 CFR 270.42 would be revised to 
reflect this classification by adding item L(9) entitled ``Initial 
Technology Changes Needed to Meet MACT Standards under 40 CFR Part 63 
(National Emission Standards for Hazardous Air Pollutants From 
Hazardous Waste Combustors)''. The prior approval under this option 
would provide for an Agency review of the proposed physical and 
operational changes to the facility before they are implemented in 
order to ensure that these changes do not lead to other undesirable 
consequences.
    Experience suggests that steps intended to reduce emissions may 
not, in all cases, lead to enhanced environmental protection. On the 
other hand, it could be argued that it should be the responsibility of 
the facility, not the permitting Agency, to assure that the regulated 
unit meets the required performance standards. EPA requests comment on 
the need for Agency oversight.
    The abbreviated procedures in options 1 through 3 would be limited 
to facilities making initial changes to existing permits in order to 
come into compliance with Sec. 112 standards. The procedures would not 
apply to general retrofitting changes outside the framework of meeting 
MACT related technology changes or to subsequent changes relating to 
maintaining compliance with Sec. 112 standards. The Agency is aware 
that the criteria for deciding on the classification of a modification 
request deviate from past decision making criteria used to 
differentiate among modification classifications in Appendix I of Part 
270. Many of the changes facilities might make to conform to the new 
standards would likely be Class 2 or 3 modifications under the current 
scheme. However, the Agency believes that a streamlined approach may be 
justified because EPA did not consider newer, more stringent standards 
becoming effective under shorter timeframes when it developed the 
current permit modification table. Also, these changes are mandated 
under a different regulatory scheme for which the modification tables 
were not designed to account. This streamlining of the modifications 
process has been addressed in the past by the Agency to ensure that 
changes made at facilities needed to meet LDR levels for newly listed 
or newly identified hazardous waste could be met (see 54 FR 9596, March 
7, 1989). These previous modifications needed to meet the LDR levels 
for newly identified wastes were redesignated as Class 1 modifications. 
These MACT standards impose more stringent operating standards than

[[Page 17456]]

current requirements; the Agency anticipates that the public will be 
receptive to these improvements and upgrades. Also, the Agency would 
still have control over the modification process under option 3 since 
it would still be reviewing the details of proposed new equipment or 
fixes to existing equipment.
    The Agency's fourth modification option, like modification option 
3, would consider all initial modification requests to existing permits 
to be Class 1 modifications requiring prior approval by the Director, 
but would give the Director the authority to elevate this modification 
to a Class 2 modification if the Director believes that additional 
public participation is warranted. This option to elevate a Class 1 
modification requiring prior approval to a Class 2 modification would 
apply only to facilities requesting modifications to comply with 
today's proposed MACT standards. It would not apply to other class 1 
modifications.
    The fifth modification option represents a ``no change'' option. 
Most modifications requested would likely be handled as Class 2 or 3 
modifications given the types of facility changes we expect in response 
to the MACT standards. Under this option, facilities would be urged to 
submit their permit modification requests as soon as possible in order 
to maximize the chances of completing the modification procedures, 
including administrative appeals, prior to the compliance deadline. EPA 
believes this alternative could thwart the Agency's chief objective of 
minimizing RCRA/CAA interface problems, and would be difficult to 
implement within the CAA compliance deadlines. Therefore, EPA does not 
favor this alternative.
    Finally, the Agency realizes that many states have not yet adopted 
the modification table in Appendix I of 40 CFR 270.42. It hopes that 
states will, at a minimum, adopt the modification scheme that is 
promulgated in the final rule to ensure expeditious implementation of 
the new MACT standards. Alternatively, if option 2 or 3 is selected in 
the final rule, States that rely on a two-tiered system of major and 
minor modifications could classify these changes as ``minor 
modifications''.
    In light of these proposed options for facilities attempting to 
comply with the MACT standards proposed in this notice, the Agency is, 
under a separate process, investigating ways to streamline the entire 
RCRA permit modification and renewal process for all industry 
categories to further reduce redundancies and inefficiencies in the 
process, while making sure that the public has adequate notice and 
involvement in the process. The Agency is in the early stages of this 
effort and wishes to solicit comment from the public on ways to achieve 
a more effective and efficient overall RCRA permit modification and 
renewal system.
2. Proposed Approaches To Address Potential Implementation Conflict
    As mentioned earlier, the Agency is also taking comment on three 
companion approaches to deal with possible permit implementation 
conflicts which may occur in the event that a state does not become 
authorized to carry out the provisions of this rulemaking in time to 
handle necessary modifications. These approaches are relevant to 
modification options 2 through 5; if option 1 is chosen, no permit 
modification will be necessary, so the issues discussed in this section 
would not arise. It is important to remember that the standards in this 
rule would take effect automatically under the CAA. Therefore, the 
facility would be obligated under that statute to make the necessary 
changes to achieve compliance. The issue discussed herein relates to 
the respective roles of EPA and authorized states in processing RCRA 
permit modification requests.
    The Agency's first approach provides a narrow interpretation of the 
scope of this rulemaking. Under this approach, only the numerical 
standards imposed by this rulemaking would be viewed as within the 
scope of this rule, and so, within the scope of HSWA. The manner in 
which facility changes are performed would be interpreted to be beyond 
the scope of the rule. Therefore, for those facilities needing a RCRA 
permit modification to reflect changes in permit conditions, the 
facility would be required to request the modification through the 
agency(ies) that implement the portion(s) of the permit to be modified.
    Under the Agency's second approach, both the proposed MACT 
standards as well as the modification(s) needed to come into compliance 
with these standards would be interpreted to fall within the scope of 
today's HSWA rulemaking. Accordingly, the Agency would make the 
modifications under HSWA for facilities in states that have not yet 
become authorized for this rule. Although this approach would 
facilitate changes, the Agency does recognize that it could potentially 
create a possibility for conflict between state and federal permit 
portions. In areas where these modifications would be inconsistent with 
currently existing state-issued portions of the facility's permit, the 
State would need to perform parallel modification procedures to correct 
the inconsistencies. In the event that a State could not do this (e.g. 
there is no ``cause for modification'' under the State regulations to 
cover the type of change that would be necessary), EPA would attempt to 
secure agreement from the state that the new HSWA conditions are more 
stringent than any inconsistent state permit conditions and take 
precedence over such conditions. The state might memorialize this 
agreement through memorandum or letter to the facility or to the 
rulemaking record. This approach might require an extensive amount of 
communication between the State and the Agency, e.g. to come to 
agreement that the HSWA change is an improvement over any conflicting 
conditions in the state portion of the permit.
    Under the Agency's third approach, in states that have not yet 
become authorized under RCRA for this rule, the Agency would not only 
modify the permit by adding conditions necessary for facilities to come 
into compliance with these MACT standards, but would also delete or 
modify conditions of the state portion of a permit if conflicts exist 
between the state- administered base program portion of a permit and 
the federally-administered HSWA portion. This approach is similar to 
the second approach, except that all modifications to any portion of a 
RCRA permit would be viewed as an integral part of EPA's role in 
carrying out the new HSWA requirements.

VII. State Authorization

A. Authority for Today's Rule

    Today's rule is being proposed under the joint authority of the 
Clean Air Act (42 U.S.C. 7401 et seq.) and RCRA (42 U.S.C. 6924(o) and 
6924(q)). The proposed approach would apply the new standards to both 
regulatory programs. Although the proposed standards would be located 
in 40 CFR Part 63, which addresses Clean Air Act requirements, the RCRA 
regulations in 40 CFR Parts 264 and 266 would incorporate these 
standards by reference. States may also promulgate these standards 
under their CAA program, and then incorporate them by reference into 
their RCRA regulations. Alternatively, States may promulgate these 
standards in both the RCRA and CAA sections of their State code for 
several reasons. Also, States without an approved CAA Title V permit 
program may promulgate these standards under their RCRA program only. 
Note however, that EPA strongly encourages States to adopt and apply 
for

[[Page 17457]]

authorization or delegation under both regulatory programs for today's 
proposed standards when finalized. (In the implementation of RCRA and 
the CAA by States, there is no functional distinction between the 
authorization of a State to implement RCRA in lieu of EPA, and the 
delegation to a State to administer the CAA. See the discussion below.) 
EPA believes that State implementation of this rule will facilitate the 
coordination between the RCRA and CAA regulatory programs.

B. Program Delegation Under the Clean Air Act

    Section 112(l) of the Clean Air Act allows EPA to approve State 
rules or programs for the implementation and enforcement of emission 
standards and other requirements for air pollutants subject to section 
112. Under this authority, EPA has developed delegation procedures and 
requirements located at 40 CFR Part 63, Subpart E, for NESHAPS under 
Title III of the CAA (See 57 FR 32250, July 21, 1992). Related 
requirements for permit programs under Title V are located at 40 CFR 
Part 70 (See 58 FR 62262, November 26, 1993).
    Under 40 CFR 70.4(a) and Sec. 502(d) of the CAA, States were 
required to submit to EPA a proposed Part 70 (Title V) permitting 
program by November 15, 1993. If a State CAA Title V program does not 
receive EPA approval by November 15, 1995, the Title V program must be 
implemented by EPA for that State.
    Submission of rules or programs by States under 40 CFR Part 63 is 
voluntary. Once a State receives approval from EPA for a standard under 
section 112(l) of the CAA, the State is delegated the authority to 
implement and enforce the approved State rules or programs in lieu of 
the otherwise applicable federal rules (the approved State standard 
would be federally enforceable). States may also apply for a partial 
Title III program, such that the State is not required to adopt all 
rules promulgated in 40 CFR Part 63. EPA will administer any rules 
federally promulgated under section 112 of the CAA that have not been 
delegated to the State.
    The section 112(l) rule for delegation under Title III (see 58 FR 
62262, November 26, 1993), is currently the subject of litigation. (See 
Louisiana Environmental Network v. Environmental Protection Agency, No. 
94-1042 (D.C. Cir., filed January 21, 1994).) The outcome of this case 
could severely limit the ability of States to receive delegation for 
air toxics standards that differ from the comparable federal standards. 
A decision is expected in early 1996.

C. RCRA State Authorization

1. Applicability of Rules in Authorized States
    Under section 3006 of RCRA, EPA may authorize qualified States to 
administer and enforce the RCRA program within the State. Following 
authorization, EPA retains enforcement authority under sections 3008, 
3013, and 7003 of RCRA, although authorized States have primary 
enforcement responsibility. The standards and requirements for 
authorization are found in 40 CFR Part 271.
    Prior to HSWA, a State with final authorization administered its 
hazardous waste program in lieu of EPA administering the Federal 
program in that State. The Federal requirements no longer applied in 
the authorized State, and EPA could not issue permits for any 
facilities that the State was authorized to permit. When new, more 
stringent Federal requirements were promulgated or enacted, the State 
was obliged to enact equivalent authority within specified time frames. 
New Federal requirements did not take effect in an authorized State 
until the State adopted the requirements as State law.
    In contrast, under RCRA section 3006(g) (42 U.S.C. 6926(g)), new 
requirements and prohibitions imposed by HSWA take effect in authorized 
States at the same time that they take effect in unauthorized States. 
EPA is directed to carry out these requirements and prohibitions in 
authorized States, including the issuance of permits, until the State 
is granted authorization to do so.
    Today's rule is being proposed pursuant to sections 3004(o) and 
3004(q), of RCRA (42 U.S.C. 6924(o) and 6924(q)), which are HSWA 
provisions. The rule would be added to Table 1 in 40 CFR 271.1(j), 
which identifies the Federal program requirements that are promulgated 
pursuant to HSWA. States may apply for final authorization for the HSWA 
provisions in Table 1, as discussed in the following section of this 
preamble.
2. Effect on State Authorization
    Today's proposed rule is considered to be more stringent than the 
existing standards in 40 CFR Parts 264 and 266. Thus, because today's 
revised technical standards for hazardous waste combustors are being 
proposed under HSWA authority, when finalized, this rule would be 
implemented by EPA in authorized States until their programs are 
modified to adopt this rule and the modification is approved by EPA. 
Note that these standards would also apply to all covered facilities 
under CAA authority, regardless of whether a State has been delegated 
the provisions of the final rule because these standards would be 
largely self-implementing.
    Because today's rule is proposed pursuant to HSWA, a State 
submitting a program modification may apply to receive interim or final 
authorization under RCRA section 3006(g)(2) or 3006(b), respectively, 
on the basis of requirements that are substantially equivalent or 
equivalent to EPA's. The procedures and schedule for State program 
modifications for final authorization are described in 40 CFR 271.21. 
It should be noted that all HSWA interim authorizations will expire 
January 1, 2003. (See Sec. 271.24(c) and 57 FR 60132, December 18, 
1992.) In addition, note that 40 CFR Part 63, Subpart E provides for 
interim approvals under the CAA only in limited circumstances.
    Section 271.21(e)(2) requires that States with final authorization 
must modify their programs to reflect Federal program changes and to 
subsequently submit the modification to EPA for approval. The deadline 
by which the State would have to modify its program to adopt these 
regulations is specified in section 271.21(e). This deadline can be 
extended in certain cases (see section 271.21(e)(3)). Once EPA approves 
the modification, the State requirements become Subtitle C RCRA 
requirements.
    States with authorized RCRA programs may already have requirements 
similar to those in today's proposed rule. These State regulations have 
not been assessed against the Federal regulations being proposed today 
to determine whether they meet the tests for authorization. Thus, a 
State is not authorized to implement these requirements in lieu of EPA 
until the State program modifications are approved. Of course, states 
with existing standards could continue to administer and enforce their 
standards as a matter of State law pending authorization for revised 
standards. In implementing the Federal program, EPA will work with 
States under agreements to minimize duplication of efforts. In most 
cases, EPA expects that it will be able to defer to the States in their 
efforts to implement their programs rather than take separate actions 
under Federal authority.
    States that submit official applications for final RCRA 
authorization less than 12 months after the effective date of these 
regulations are not required to include standards equivalent to these 
regulations in their application.

[[Page 17458]]

However, the State must modify its RCRA program by the deadline set 
forth in Sec. 271.21(e). States that submit official applications for 
final authorization 12 months after the effective date of these 
regulations must include standards equivalent to these regulations in 
their application. The requirements a State must meet when submitting 
its final authorization application are set forth in 40 CFR 271.5.
3. Streamlined Authorization Under RCRA
    Recently, EPA has initiated a series of rulemakings intended to 
streamline and speed the State authorization of RCRA rules. On August 
22, 1995, EPA proposed abbreviated authorization procedures for certain 
routine Land Disposal Restrictions (LDR) provisions as part of the 
Phase IV LDR rule (see 60 FR 43654 and 43686). This proposal would 
implement streamlined authorization procedures for certain minor and 
routine rulemakings for those States which certify that they have 
authority equivalent to and no less stringent than the federal rule. 
EPA believes that the abbreviated authorization procedures proposed in 
the August 22, 1995, proposal would be appropriate for RCRA Subtitle C 
authorization for those States that are approved to implement this rule 
pursuant to 40 CFR Part 63, Subpart E, and are simply incorporating 
this rule into their RCRA regulations. EPA requests comment regarding 
the use of this proposed procedure for this authorization scenario. 
Note however, that EPA is not proposing to use RCRA authorization as a 
substitute for CAA section 112(l) approvals.
    The primary reason that EPA is proposing to use an abbreviated 
authorization procedure when States are approved to implement this rule 
under the CAA, is that the delegation process and requirements in Part 
63 are similar to authorization under 40 CFR 271.21. For example, 
section 112(l)(1) of the CAA requires that a program submitted by a 
State ``shall not include authority to set standards less stringent 
than those promulgated by the Administrator.'' Further, section 116 of 
the CAA precludes a State from adopting or enforcing less stringent 
standards than those under section 112. See 40 CFR Secs. 63.12(a)(1), 
271.1(h), and section 3009 of RCRA. States may also establish more 
stringent requirements as long as they are not inconsistent with the 
CAA. Further, section 112(l)(5)(A) of the CAA requires States to have 
adequate authorities to ensure compliance, similar to the requirement 
in section 3006(b) of RCRA. Thus, for EPA to approve a State rule or 
program, the procedures and criteria in 40 CFR 63.91(b) must be met, as 
well as any applicable requirements of Secs. 63.92 through 63.94. These 
requirements are equivalent to those under RCRA. Therefore, using an 
abbreviated RCRA authorization procedure would prevent States from 
going through substantial authorization procedures under both the CAA 
program and the RCRA program.
    EPA is also committed to streamlining the authorization process for 
States that would not be incorporating delegated CAA standards stemming 
from the final rule. EPA believes that authorized States have 
experience implementing sophisticated combustion regulatory programs 
and would have the ability to effectively implement today's proposed 
standards. Thus, EPA requests comment on whether all States that are 
authorized for the incinerator regulations under 40 CFR Part 264 and 
the Boiler and Industrial Furnace (BIF) regulations should use the 
authorization procedure proposed on August 22, 1995. EPA is also 
developing a second authorization procedure for those RCRA rules which 
have more significant impacts on State hazardous waste programs that is 
slightly more extensive than the procedure proposed on August 22, 1995. 
This second procedure is also intended to significantly streamline the 
authorization process, and will be described in detail in the upcoming 
Hazardous Waste Identification Rule (HWIR) proposal for contaminated 
media. EPA believes that this second procedure may be more appropriate 
for today's proposal, given its significance and complexity. In the 
upcoming HWIR-Media proposal, EPA will request comment whether this 
procedure should be used for RCRA authorization in this case.

VIII. Definitions

    Many of the terms used in today's proposal have been defined either 
in the Clean Air Act or in existing Sec. 63.2. For terms that are not 
already defined, we are proposing definitions in Sec. 63.1201. In 
addition, we are proposing conforming definitions to the existing RCRA 
regulations in Secs. 260.10 and 270.2.

A. Definitions Proposed in Sec. 63.1201

    We are proposing definitions for the following terms in 
Sec. 63.1201: Air Pollution Control System, Automatic Waste Feed Cutoff 
System, Cement Kiln, Combustion Chamber, Compliance Date, Comprehensive 
Performance Test, Confirmatory Performance Test, Continuous Monitor, 
Dioxins and Furans, Feedstream, Flowrate, Fugitive Combustion 
Emissions, Hazardous Waste, Hazardous Waste Combustor, Hazardous Waste 
Incinerator, Initial Comprehensive Performance Test, Instantaneous 
Monitoring, Lightweight Aggregate Kiln, Low Volatility Metals, New 
Source, Notification of Compliance, One-Minute Average, Operating 
Record, Reconstruction, Rolling Average, Run, Semivolatile Metals, and 
TEQ.
    We believe that the definitions of these terms is self-explanatory 
as proposed.

B. Conforming Definitions Proposed in Secs. 260.10 and 270.2

    To avoid confusion and ambiguity, we are proposing conforming 
definitions in Secs. 260.10 and 270.2 for the following terms that 
pertain to implementation of the current RCRA requirements and RCRA 
requirements that would not be superseded by the proposed MACT 
standards: RCRA operating permit, DRE performance standard, closure and 
financial responsibility requirements, addition of permit conditions as 
warranted on a site-specific basis to protect human health and the 
environment.
    Because these definitions pertain to existing RCRA requirements, 
the effective date for the definitions would be six months after the 
date of publication in the Federal Register.

C. Clarification of RCRA Definition of Industrial Furnace

    Today's proposed rule applies to combustion units that are already 
subject to regulation under RCRA. These devices are presently 
classified as hazardous waste incinerators or hazardous waste-burning 
industrial furnaces, depending on their mode of operation. As discussed 
below, the distinctions between these classifications (i.e., 
incinerator and industrial furnace) are important in determining the 
level for Clean Air Act technology-based standards and also in applying 
a variety of RCRA regulatory provisions.
    From the RCRA perspective, the distinction between incinerators and 
industrial furnaces (and boilers, for that matter) is important, among 
other things, for determining facility eligibility for interim status, 
the regulatory regime for classification of combustion residue (i.e., 
for example, product or non-product), and eligibility for Bevill status 
for combustion residue. EPA defines industrial furnaces as those 
designated devices that are an integral part of a manufacturing process 
and that use thermal treatment to recover materials or energy. 40 CFR 
260.10.

[[Page 17459]]

Other criteria in the rule indicate what it means to be an ``integral 
part of a manufacturing process.'' The RCRA rules thus set out 
``aspects of industrial furnaces that distinguish them from hazardous 
waste incinerators'', 48 FR 14472, 14483 (April 4, 1983); 50 FR 614, 
626-27 (January 4, 1985). These include whether the device is designed 
and used ``primarily to accomplish recovery of material products'', the 
``use of the device to burn or reduce raw materials to make a material 
product'', ``the use of the device to burn or reduce secondary 
materials as effective substitutes for raw materials, in processes 
using raw materials as principal feedstocks'', ``the use of the device 
to burn or reduce secondary materials as ingredients in an industrial 
process to make a material product'', and ``the use of the device in 
common industrial practice to produce a material product. 40 CFR 
260.10.
    EPA interprets the regulatory definition of industrial furnace as 
applying only to devices that are enumerated in the rule and that also 
satisfy the narrative portion of the definition, that is, functions as 
an integral part of a manufacturing process, taking into account the 
narrative criteria in the rule. Thus, for example, if a device which is 
otherwise a cement kiln is not used as an integral component of a 
manufacturing process, it is not an industrial furnace. See 56 FR at 
7140, 7141 (February 21, 1991) (Device-by-device application of 
industrial furnace regulatory definition); 48 FR at 14485 (April 4, 
1983) (same). A cement kiln used primarily to burn contaminated soil 
from Times Beach so as to destroy dioxins thus is not an industrial 
furnace because it would not be an integral component of a 
manufacturing process but essentially a waste treatment unit. Among 
other things, it would not be used ``primarily for recovery of material 
products.'' 40 CFR 260.10(13)(I); See also Background Document for the 
Regulatory Definition of Boiler, Incinerator, and Industrial Furnace 
(October 1984), at page 6. Conversely, a cement kiln making cement from 
raw materials but burning some hazardous waste for destruction as an 
adjunct to its normal activities could be classified as an industrial 
furnace.
    Industrial furnaces burning hazardous wastes for any purpose--
energy recovery, material recovery, or destruction--are currently 
subject to the rules for BIFs in Part 266 subpart H. 56 FR at 7138; 40 
CFR 266.100. In this regard, the BIF rule changed the previous 
regulatory regime whereby if a combustion device burned hazardous waste 
for destruction, it was regulated as an incinerator no matter what the 
proportion of burning for destruction to other activities. 40 CFR 
264.340(a) and 265.340(a) as promulgated at 50 FR at 665-66 (January 4, 
1985); 48 FR at 14484 and n. 15 (April 4, 1983). However, a device must 
still satisfy the regulatory definition of industrial furnace, and thus 
must in the first instance be an integral component of a manufacturing 
process. This means, among other things, that enclosed combustion 
devices that burn hazardous wastes for destruction may not be 
industrial furnaces. See 1984 Background Document for Definition of 
Boiler, Incinerator, and Industrial Furnace (cited above), page 6. This 
is because hazardous waste destruction devices may not be designing and 
using the device primarily to accomplish recovery of material products, 
may not be using the device to combust secondary materials as effective 
substitutes for raw materials, etc.\184\
---------------------------------------------------------------------------

    \184\ The Administrator specifically rejects the contrary 
suggestion of the Agency's Environmental Appeals Board that ``the 
purpose for which hazardous waste is burned at the facility has 
little or no bearing on whether the facility meets the industrial 
furnace definition.'' In re Marine Shale Processors, Inc., RCRA 
Appeal No. 94-12 (March 17, 1995) p. 25 n. 32.
---------------------------------------------------------------------------

PART SIX: MISCELLANEOUS PROVISIONS AND ISSUES

I. Comparable Fuel Exclusion

    EPA is proposing to exclude from the definition of solid and 
hazardous waste materials that meet specification levels for 
concentrations of toxic constituents and physical properties that 
affect burning. Generators that comply with sampling and analysis, 
notification and certification, and recordkeeping requirements would be 
eligible for the exclusion.\185\ See proposed Sec. 261.4(a)(13).
---------------------------------------------------------------------------

    \185\ We note that DOW Chemical Company (Dow) in a petition to 
the Administrator, dated August 10, 1995, specifically requested 
that the Agency develop a generic exclusion for ``materials that are 
burned for energy recovery in on-site boilers which do not exceed 
the levels of fossil fuel constituents. . . . '' (Petition, at p. 
3). This proposal also responds to that petition.
---------------------------------------------------------------------------

    Hazardous waste is burned for energy recovery in boilers and 
industrial furnaces in lieu of fossil fuels. There are benefits to this 
energy recovery in the form of diminished use of petroleum-based fossil 
fuels. Industry sources contend that in some cases, hazardous waste 
fuels can be ``as clean or cleaner'' (meaning they present less risk) 
than the fossil fuels they displace. This claim has not been documented 
with full emissions and risk analysis. Industry further contends that 
currently regulating these materials under normal hazardous waste 
regulations acts as a disincentive to using them as fuels.
    EPA's goal is to develop a comparable fuel specification which is 
of use to the regulated community but assures that an excluded waste is 
similar in composition to commercially available fuel and poses no 
greater risk than burning fossil fuel. Accordingly, EPA is using a 
``benchmark approach'' to identify a specification that would ensure 
that constituent concentrations and physical properties of excluded 
waste are comparable to those of fossil fuels. We note that this is 
consistent with the main approach discussed in the Dow Chemical Company 
petition of August 10, 1995, which also points out a number of benefits 
that would result from promulgating this type of exemption: (1) support 
for the Agency's goal of promoting beneficial energy recovery and 
resource conservation; (2) reduction of unnecessary regulatory burden 
and allowing all parties to focus resources on higher permitting and 
regulatory priorities; and (3) demonstration of a common-sense approach 
to regulation.\186\
---------------------------------------------------------------------------

    \186\ We also note there are other details in the DOW petition 
that are congruent with aspects of today's proposal. The Agency 
specifically invites comment on the DOW petition as part of this 
rulemaking.
---------------------------------------------------------------------------

    The rationale for the Agency's approach is that if a secondary 
material-based fuel is comparable to a fossil fuel in terms of 
hazardous and other key constituents and has a heating value indicative 
of a fuel, EPA has ample authority to classify such material as a fuel 
product, not a waste. Indeed, existing rules already embody this 
approach to some degree. Under Sec. 261.33, commercial chemical 
products such as benzene, toluene, and xylene are not considered to be 
wastes when burned as fuels because normal fossil fuels can contain 
significant fractions of these chemicals and these chemicals have a 
fuel value. Given that a comparable fuel would have legitimate energy 
value and the same hazardous constituents in comparable concentrations 
to those in fossil fuel, classifying such material a non-waste would 
promote RCRA's resource recover goals without creating any risk greater 
than those posed by the commonly used commercial fuels. Under these 
circumstances, EPA can permissibly classify a comparable fuel as a non-
waste. See also 46 FR at 44971 (August 8, 1981) exempting from Subtitle 
C regulation spent pickle liquor used as a wastewater treatment agent 
in part because of its similarity in composition to the commercial 
acids that would be used in its place.

[[Page 17460]]

    As discussed below, EPA seeks comment on a number of options 
including what fossil fuel or fuels should be used as a benchmark, and 
how to select appropriate specification limits given the range of 
values both within and across fuel types. EPA also requests additional 
data on hazardous constituents naturally occurring in commercially 
available fuels. (The Agency's current data on fossil fuel composition 
are provided in the docket to this rulemaking.)
    Also, the exclusion would operate from the point of fuel generation 
to the point of burning. Thus, the fuel's generator would be eligible 
for the exclusion and could either burn the excluded comparable fuel on 
site or ship it off-site directly to a burner. Thus, the Agency must 
ensure that storage and transportation of excluded comparable fuel 
poses no greater hazard than fossil fuel. The Agency invites comment on 
whether the applicable Department of Transportation (DOT) and Office of 
Occupational Safety and Health (OSHA) requirements are adequate to 
address this concern so that separate, potentially duplicative RCRA 
regulation would not be needed.
    Note also that, because EPA is proposing to eliminate or amend 
other combustion-related exemptions in this rulemaking (i.e., the 
exemption for incinerators for wastes that are hazardous solely because 
they are ignitable, corrosive, or reactive and contain no or 
insignificant levels of Appendix VIII, Part 261, toxic constituents; 
and the low-risk waste exemption under BIF), the inclusion of a 
comparable fuels exemption may offset the effects of these changes at a 
number of affected facilities.
    EPA also invites comment on whether acutely hazardous wastes should 
be ineligible for the exemption. See the section called ``CMA Clean 
Fuel Proposal'', below, for what is considered an acutely hazardous 
waste.

A. EPA's Approach to Establishing Benchmark Constituent Levels

1. The Benchmark Approach
    EPA considered using risk to human health and the environment as 
the way to determine the scope and levels of a ``clean fuels'' 
specification. However, the Agency encountered several technical and 
implementation problems using a purely risk-based approach. 
Specifically, we have insufficient data relating to the types of waste 
burned and the risks they pose. To pursue a risk-based ``clean fuels'' 
approach, EPA needs to examine emissions from a number of example 
facilities at which ``clean fuel'' would be burned. The Agency could 
then analyze risks while the facility is burning the ``clean fuel''. 
EPA also does not have sufficient data to determine the relationship 
between the amount of ``clean fuel'' burned and emissions, especially 
dioxins and other non-dioxin PICs. EPA also does not know how emissions 
relate to real individual facilities as compared to example facilities 
used to derive the ``clean fuel'' specification. (Emissions and/or 
risks at a given facility could be higher than those of the example 
facilities given site-specific considerations.) Without this, it is not 
clear how the Agency can use risk to establish a ``clean fuel'' 
specification. The Agency requests data and invites comment on deriving 
a risk based specification.
    The Agency is instead proposing to develop a comparable fuel 
specification, based on the level of hazardous and other constituents 
normally found in fossil fuels. EPA calls this the ``benchmark 
approach''. For this approach, EPA would set a comparable fuel 
specification such that concentrations of hazardous constituents in the 
comparable fuel could be no greater than the concentration of hazardous 
constituents naturally occurring in commercial fossil fuels. Thus, EPA 
would expect that the comparable fuel would pose no greater risk when 
burned than a fossil fuel and would at the same time be physically 
comparable to a fossil fuel.
2. The Comparable Fuel Specification
    EPA is proposing to use this benchmark approach to develop a series 
of technical specifications addressing:
    (1) physical specifications:

--Kinematic viscosity (cST at 100 deg. F),
--Flash point ( deg.F or  deg.C), and
--Heating value (BTU/lb);

    (2) general constituent specifications for:

--Nitrogen, total (ppmw), and
--Total Halogens (ppmw, expressed as Cll-), including chlorine, 
bromine, and iodine; \187\ and

    \187\ See discussion below concerning another halogen, fluorine.
---------------------------------------------------------------------------

    (3) individual hazardous constituent specifications, for:

--Individual Metals (ppmw), including antimony, arsenic, barium, 
beryllium, cadmium, chromium, cobalt, lead, manganese, mercury, nickel, 
selenium, silver, and thallium, and
--Individual Appendix VIII, Part 261, Toxic Organics and Fluorine 
(ppmw).

(Note that ppmw is an alternate way of expressing the units mg/kg.) The 
constituent specifications and heating value would apply to both gases 
and liquids. The flash point and kinematic viscosity would not apply to 
gases. EPA invites comment on whether this list of specifications 
should be expanded to include other parameters, specifically ash and 
solids content, to ensure that excluded comparable fuels have the same 
handling and combustion properties as fossil fuels.
    There are existing specifications for fossil fuels that are 
developed and routinely updated by the American Society for Testing and 
Materials (ASTM). (See ASTM Designation D 396 for fuel oils and D 4814 
for gasoline.) These requirements specify limits for physical 
properties of fossil fuels, such as flash point, water and sediment, 
distillation temperatures,\188\ viscosity, ash, sulfur, corrosion, 
density, and pour point. The ASTM requirements do not limit specific 
constituents in fuel. As a result, fossil fuels are quite diverse in 
their hydrocarbon constituent make-up. Specific levels of hydrocarbon 
constituents are a function of the crude oil, the processes used to 
generate the fuels, and the blending that occurs. This makes ASTM 
requirements for fuels of no use for deriving individual hazardous 
constituent specifications, but useful for deriving physical 
specifications. EPA invites comment on whether ASTM's physical 
specifications for flash point and viscosity should be used instead of 
the results of EPA's analysis.189 190
---------------------------------------------------------------------------

    \188\ The temperature at which a certain volumetric fraction of 
the fuel has distilled.
    \189\ The issue is that all analytical results should meet 
ASTM's specifications. Thus, basing a specification limit on 
analysis of samples will result in limits more restrictive than the 
ASTM specification defining an acceptable fuel.
    \190\ ASTM does not specify a heating value requirement.
---------------------------------------------------------------------------

    a. Standards for CAA Metal HAPs. EPA is proposing limits for two 
metals that are not found on Part 261, Appendix VIII: cobalt and 
manganese. EPA included these metals in the analysis because they are 
listed in the Clean Air Act (CAA) as hazardous air pollutants (HAPs). 
See CAA, section 112(b). These metals are included because burning does 
not destroy metals, and will cause the release of metals into the air. 
Therefore, if a comparable fuel contained more of a metal than a fossil 
fuel, the result would be more air emissions of that metal than would 
be the case if the facility burned only fossil fuels. From a CAA 
perspective, it would not be acceptable to increase emissions of CAA 
HAP metals, relative to what would be emitted if fossil fuels were 
burned.

[[Page 17461]]

Therefore, constituent levels (or detection limits) for the two CAA 
HAPs are proposed as well.
    b. Heating Value. With respect to heating value, the Agency is 
concerned with the issues of overall environmental loading and 
acceptability of the waste as a fuel. Comparable fuels may have a lower 
heating value than the fossil fuels they would displace. In these 
situations, more comparable fuels would be burned to achieve the same 
net heating loads, with the result that more of the hazardous 
constituents in the comparable fuel would be emitted (e.g., halogenated 
organic compounds and metals) than if fossil fuel were to be burned. 
This would lead to greater environmental loading of potentially toxic 
substances, which is not in keeping with the intent of the comparable 
fuels exclusion.
    To address environmental loading, the Agency could establish a 
minimum heating value specification comparable to the BTU content of 
the benchmark fossil fuel(s). Fossil fuels have a higher heating value 
than most hazardous waste fuels, however; so this approach might 
exclude many otherwise suitable fuels. Therefore the Agency chose to 
establish the specification(s) for comparable fuels at a heating value 
of 10,000 BTU/lb.\191\ EPA chose 10,000 BTU/lb because it is typical of 
current hazardous waste burned for energy recovery.\192\ However, 
hazardous waste fuels have a wide range of heating values. Therefore, 
EPA is proposing that, when determining whether a waste meets the 
comparable fuel constituent specifications, a generator must first 
correct the constituent levels in the candidate waste to a 10,000 BTU/
lb heating value basis prior to comparing them to the comparable fuel 
specification tables. In this way, a facility that burns a comparable 
fuel would not be feeding more total mass of hazardous constituents 
than if it burned fossil fuels.\193\
---------------------------------------------------------------------------

    \191\ Constituent levels presented in today's proposed rule have 
been corrected from the fuel's heating value (approximately 20,000 
BTU/lb) to 10,000 BTU/lb.
    \192\ Consult USEPA, ``Draft Technical Support Document for HWC 
MACT Standards, Volume II: HWC Emissions Database'', February 1996.
    \193\ Note that the heating value correction would apply only to 
allowable constituent levels in fuels, not to detection limits. 
Detection limits would not be corrected for heating value.
---------------------------------------------------------------------------

    Also, EPA wants to ensure that currently defined wastes which meet 
the comparable fuels exclusion have a legitimate use as a fuel. 
Historically, the Agency has relied on a heating value of 11,500 J/g 
(5,000 BTU/lbm) as a minimum heating value specification for 
determining if a waste is being burned for energy recovery. (See 
Sec. 266.103(c)(2)(ii).) EPA proposes this limit today as a minimum 
heating value for a comparable fuel to ensure that comparable fuels are 
legitimate fuels.
    c. Applicability of the specifications. A separate issue is the 
applicability of these specifications. EPA is proposing that these 
specifications apply to all gases and liquids currently defined as 
hazardous wastes. (However as noted elsewhere, used oil, and used crude 
oil that is also a hazardous waste, would remain subject to regulation 
as used oil under 40 CFR Part 279, even if it meets the comparable fuel 
specifications.) The specifications for viscosity and flash point would 
only pertain to liquid fuels. This is because gases are inherently less 
viscous than liquids and flash point does not apply to gases. 
Therefore, EPA proposes that the specifications for viscosity and flash 
point not apply to gaseous comparable fuels.
    d. Organic Constituent Specifications. With respect to Appendix 
VIII organic toxic constituents and other toxic synthetic chemicals, 
such as pesticides and pharmaceuticals, the Agency needs to ensure that 
only waste fuels comparable to fossil fuels are excluded. Therefore, 
the Agency proposes to limit the Appendix VIII constituents in 
comparable fuels to those found in the benchmark fossil fuel. These 
limits were calculated using a statistical analysis of individual 
samples EPA obtained.
    If the benchmark fossil fuel has no detectable level of a 
particular Appendix VIII constituent, then the comparable fuel 
specification would be ``non-detect'' with an associated, specified 
maximum allowable detection limit for each compound. (Note exception in 
the following section.) The detection limit is a statistically derived 
level based on the quantification limit determined for each sample.
    There are also compounds found on Appendix VIII which were not 
analyzed for, either because an analytical method is not available or 
could not be identified in time for this analysis. These compounds are 
not listed in today's specifications. If EPA is able to identify 
methods for analyzing these compounds and is able to analyze for these 
compounds prior to promulgation, an appropriate specification level or 
detection limit will be promulgated for Appendix VIII compounds missing 
from today's specification. If EPA is not able to analyze for compounds 
on Appendix VIII, we propose that the standard for these remaining 
Appendix VIII constituents be ``nondetect'' without a maximum detection 
limit proposed.
    e. Specification Levels for Undetected Pure Hydrocarbons. A 
corollary issue is that, since fossil fuels are comprised almost 
entirely of pure hydrocarbons 194 in varying concentrations, it is 
possible that many pure hydrocarbons on Appendix VIII, Part 261, could 
be present in fossil fuel but below detection limits. Therefore, EPA 
proposes allowing pure hydrocarbons on Appendix VIII to be present up 
to the detection limits in EPA's analysis. Compounds on Appendix VIII 
which contain atoms other than hydrogen and carbon would be limited to 
``non-detect'' levels as described in the previous paragraph.
---------------------------------------------------------------------------

    \194\ Excluding sulfur, carbon and hydrogen comprise 99.6 to 100 
percent of liquid fossil fuels.
---------------------------------------------------------------------------

    f. Specification Levels for Other Fuel-like Compounds. In addition 
there are classes of fuel-like compounds that are not found in fossil 
fuels. These include oxygenates, an organic compound comprised solely 
of hydrogen, carbon, and oxygen above a minimum oxygen-to-carbon ratio. 
Examples of oxygenates which are used as fuels or fuel additives 
include alcohols such as methanol and ethanol, and ethers such as 
Methyl tert-butyl ether (MTBE).195 However, Appendix VIII 
oxygenates are not routinely found in fossil fuels and were not 
detected in EPA's sampling and analysis program.196 Since 
oxygenates can serve as fuels and are believed to burn well (i.e., may 
not produce significant PICs), EPA invites comment on: (1) whether 
these compounds should also be allowed up to the detection limits in 
EPA's analysis; and (2) an appropriate minimum oxygen-to-carbon ratio 
to identify an oxygenate.
---------------------------------------------------------------------------

    \195\ A compound such as 2,3,7,8-TCDD is not an oxygenate since 
it contains atoms other than hydrogen, carbon, and oxygen. Compounds 
such as Dibenzo-p-dioxin and Dibenzofuran are not oxygenates even 
though they are comprised solely of hydrogen, carbon, and oxygen 
because the oxygen-to-carbon ratio is too low.
    \196\ See the appendix for this notice for the results of EPA's 
analysis.
---------------------------------------------------------------------------

    g. Total Halogen Specification and Fluorine. Another issue is that 
the methods for determining total halogens do not measure fluorine, the 
lightest of the halogen compounds. Fluorine is, however, listed as an 
Appendix VIII constituent and methods are available for measuring 
fluorine directly. Therefore, EPA proposes that the total halogen limit 
pertain only to halogens other than fluorine, i.e., chlorine, bromine, 
and iodine. EPA also proposes that a fluorine limit be established 
separately from the total halogen limit. Specification values for 
fluorine are included in the specifications described below.
    h. Specification Levels for Halogenated Compounds. EPA invites 
comment on whether it is necessary to

[[Page 17462]]

specify limits for halogenated compounds found on Appendix VIII. 
Nondetect levels of halogens were found in EPA's fossil fuel analysis 
and the nondetect levels for total halogens were much less than those 
of the individual halogenated compounds. Therefore, a waste that meets 
the total halogen limit should, by default, meet the non-detect levels 
specified for halogenated compounds. EPA prefers this approach since it 
will simplify the comparable fuels specification and mean fewer and 
less costly sampling and analysis of comparable fuel streams for 
generators. We invite comment on this approach.
    EPA also invites comment on whether this approach could be expanded 
to other Appendix VIII constituents as well (e.g., whether the total 
nitrogen specification level would ensure compliance with specification 
levels for individual compounds containing nitrogen).
3. Selection of the Benchmark Fuel
    Another issue is selecting the appropriate fossil fuel(s) for the 
benchmark, and therefore the basis of the comparable fuel 
specification. Commercially available fossil fuels are diverse. They 
range from gases, such as natural gas and propane, to liquids, such as 
gasoline and fuel oils, to solids, such as coal, coke, and peat.
    EPA does not believe, from an environmental standpoint, that the 
comparable fuel specification, which would exclude a hazardous waste 
fuel from RCRA subtitle C regulation, should be based on fossil fuels 
that have high levels of toxic constituents that may (or will) not be 
destroyed or detoxified by burning (e.g., metals and halogens). One 
would expect that solid fuels, such as coal, would have relatively high 
metal and possibly halogen levels. Metals and halogens are not 
destroyed in the combustion process and as a result can lead to 
increases in HAP emissions, unlike organic Appendix VIII constituents 
which (ideally) are destroyed or detoxified through combustion. 
Therefore, EPA is not inclined to include a solid fuel as a benchmark 
fuel. Also, we believe that basing the comparable fuel specification on 
a gas fuel would be overly conservative and have no utility to the 
regulated industry. Liquid fuels, on the other hand, are widely used by 
industry and do not have disadvantages of solid or gaseous fuels. 
Liquid fuels seem a good compromise among the fuel types. The Agency is 
therefore proposing to base the comparable fuel specification on 
benchmark liquid fuels.
    However, even liquid fossil fuels are diverse and add to the 
complexity of selecting a benchmark fuel. For instance, gasoline has 
relatively higher levels of toxic organics, such as benzene and toluene 
but lower concentrations of metals. Conversely, we have also found and 
would continue to expect that typical fuel oils have lower 
concentrations of toxic organics and higher concentrations of metals 
than gasoline. We also have found that heavier fuel oils (e.g., No. 6) 
contain more metals than lighter fuel oils (e.g., No. 2).197
---------------------------------------------------------------------------

    \197\ See the appendix to this notice for the results of EPA's 
analysis.
---------------------------------------------------------------------------

    In addition, EPA could choose a vegetable oil-based fuel, such as 
``tall oil'', rather than a fossil fuel. EPA has no data on 
concentrations of hazardous constituents in these fuels, however. Also, 
these fuels are not as widely used as commercial fuels. In keeping with 
the benchmark approach, EPA believes it is appropriate to base the 
comparable fuel specification on an appropriate and widely used type of 
commercial fuel, i.e., fossil fuels.
    We specifically request constituent data for gasoline, automotive 
diesel, and No. 1 (kerosene/Jet fuel), No. 2 (different from automotive 
diesel), No. 4, and No. 6 fuel oils. These data should be complete and 
include analyses for all Appendix VIII constituents including nondetect 
values. When supplying data during the comment period, commenters 
should follow the same analytical and quality procedures EPA used. It 
would assist the Agency greatly if the data were supplied in electronic 
(1.44-MB PC or Macintosh floppy disk) as well as hard-copy form. 
Electronic versions should be in a spreadsheet form (for instance, 
Lotus 1,2,3, or Microsoft Excel) or an ASCII file with a description of 
how the records are classified/organized into which fields. Consult the 
Technical Background Document for a complete list of constituents and 
additional information concerning EPA's sampling and analysis and 
quality assurance protocols used.

B. Sampling, Analysis, and Statistical Protocols Used

    This section describes the sampling, analysis, and statistical 
protocols used to derive the comparable fuels specifications described 
below. For more detailed discussion, refer to the Technical Background 
Document.
1. Sampling
    EPA obtained a total of 27 fossil fuel samples. They were comprised 
of eight gasoline and eleven No. 2, one No. 4, and seven No. 6 fuel oil 
samples. The samples were collected at random from sources across the 
country: Irvine, CA; north west New Jersey; north east Connecticut; 
Coffeyville, KS; Fredonia, KS; Norco, LA; Hopewell, VA; and Research 
Triangle Park, NC.
    Only one No. 4 fuel oil sample was obtained. Very little ``No. 4'' 
fuel oil 198 is sold in the United States. Rather, what is used as 
No. 4 is essentially a blend of No. 2 and 6 fuel oils. These blends 
vary, are contract specific, and are not No. 4 fuel oil, per se. EPA 
specifically requests data on (genuine) No. 4 fuel oil constituent 
levels.
---------------------------------------------------------------------------

    \198\ No. 4 fuel oil is defined as fuel that meets the physical 
specifications established by the American Society of Testing and 
Materials.
---------------------------------------------------------------------------

2. Analysis of the Fuel Samples
    Analytical methods have not been defined for all compounds on Part 
261, Appendix VIII. Where analytical methods have not been defined, 
analysis of those constituent levels in fossil fuels are not possible. 
However, EPA is working on identifying methods for compounds on 
Appendix VIII which were not analyzed for during this initial analysis. 
If EPA is able to identify analysis methods for these compounds, 
constituent specifications for these compounds will be included in the 
final rule using the same methodology for constituent specifications 
described in today's notice.
    After the samples were obtained, they were analyzed at a laboratory 
accustomed to analyzing fossil fuels. SW-846 methods were used whenever 
possible. Where SW-846 methods were not available, established ASTM 
procedures or other EPA methods for fuel analyses were used. Table 
VI.1.1 summarizes the analytical methods used.

   Table VI.1.1: Analytical Methods Used for Comparable Fuels Analysis  
------------------------------------------------------------------------
           Property of interest                        Method           
------------------------------------------------------------------------
Heating Value.............................  EPA 325.3/PARR.             
Kinematic Viscosity.......................  ASTM D240.                  
Flash Point...............................  SW-846 1010.                
Total Nitrogen............................  ASTM D4629.                 
Total Halogens............................  EPA 325.3/PARR.             
Antimony..................................  SW-846 7040.                
Arsenic...................................  SW-846 7060.                
Barium....................................  SW-846 7080.                
Beryllium.................................  SW-846 7090.                
Cadmium...................................  SW-846 7130.                
Chromium..................................  SW-846 7190.                
Cobalt....................................  SW-846 7200.                
Lead......................................  SW-846 7420.                
Manganese.................................  SW-846 7460.                
Mercury...................................  SW-846 7470.                
Nickel....................................  SW-846 7520.                
Selenium..................................  SW-846 7740.                
Silver....................................  SW-846 7760.                

[[Page 17463]]

                                                                        
Thallium..................................  SW-846 7840.                
Appendix IX Volatile Organics.............  SW-846 8240.                
Appendix IX Semivolatile Organics.........  SW-846 8270.                
------------------------------------------------------------------------



    In addition, the analysis was conducted in such a way as to ensure 
the lowest detection limits, also called ``quantification limits,'' 
possible. Detection limits were determined by calculating the ``method 
detection limit'' (MDL) for each analysis. To do this, EPA used a 
modified version of the procedures defined by EPA in 40 CFR 136, 
Appendix B, Definition and Procedure for Determination of Method 
Detection Limits, Revision 1.1. The modification involved spiking for 
each of the samples being analyzed instead of spiking once for all the 
samples, as stated by the method.
    One issue concerning the analysis is that, even when attempts are 
made to minimize detection limits, detection limits can still be 
extremely high. This is particularly so for volatile organic compounds 
in the gasoline samples. There is no feasible analytical way to address 
this issue, so it is addressed when deriving the comparable fuel 
specification.
3. Statistical Procedures Used
    Due to the small sample sizes of each fuel type, EPA used a 
nonparametric ``order statistics'' approach to analyze the fuel data. 
If enough data are received to determine the distribution of the 
enlarged data set, statistical procedures appropriate to the 
distribution, i.e., different than those described here, may be used 
for the promulgated specification.
    ``Order statistics'' involves ranking the data for each constituent 
from lowest to highest concentration, assigning each data point a 
percentile value from lowest to highest percentile, respectively. 
Result percentiles were then calculated from the data percentiles. 
Consult the Technical Background document for more information 
regarding the statistical approach.
    EPA is considering using either the 90th or 50th percentile values 
to determine the comparable fuel specification. If the exclusion were 
to be based on specifications from one or more individual benchmark 
fuels (e.g., separate gasoline or fuel oil based specifications), EPA 
believes it is more appropriate to establish the specification(s) based 
on the 90th percentile rather than the 50th percentile values. The 90th 
percentile represents an estimate of an upper limit of what is in a 
particular fuel while the 50th percentile values would exclude up to 50 
percent of the fossil fuel samples. For composite specifications 
(discussed in detail below), EPA is considering using either the 50th 
or 90th percentile, but the considerations differ. A 50th percentile 
analysis was conducted because it represents what, ``on average'', is 
found in all potential benchmark fuels that were studied. A 90th 
percentile was also conducted because it represents the upper bound of 
what is found in all fuels. EPA invites comment on which percentile(s) 
is appropriate for both the individual specifications as well as the 
composite specification.

C. Options for the Benchmark Approach

    As just described, EPA has several options for deciding what fossil 
fuel(s) to use as the benchmark. The following options range from 
developing a suite of comparable fuel specifications based on 
individual benchmark fuels (i.e., gasoline, No. 2, No. 6) to basing the 
specification on composite values derived from the analysis of all 
benchmark fuels.
    The Agency invites comment on which of the following options should 
be selected. Again, EPA desires to provide constructive relief to the 
regulated community by having a comparable fuel specification that can 
be used in practice. On the other hand, EPA needs to ensure that the 
release of toxic compounds is not increased significantly by burning 
comparable fuels in lieu of fossil fuels. For this reason, we are 
offering several options for comment. Commenters should also address in 
their comments the justification needed to support their preferred 
option.
    The options discussed below are not the only possible options. If 
commenters have other options they wish the Agency to consider, they 
should recommend them and explain how they meet the objectives of a 
benchmark approach to comparability.
1. Individual Benchmark Fuel Specifications
    Under this option, EPA invites comment on establishing individual 
specifications based on the benchmark fuels for which EPA has obtained 
data: gasoline, and No. 2 and No. 6 fuel oils.\199\ \200\ Each would 
have a unique set of constituent and physical specifications, based on 
the individual benchmark fossil fuel. A generator would use one of 
these specifications (after correcting for heating value) to determine 
if a waste qualifies for the exclusion. As mentioned in subsection 
A.2.B., above, heating value of a comparable fuel would have to exceed 
11,500 J/g (5,000 BTU/lbm).
---------------------------------------------------------------------------

    \199\ This list could be expanded, depending on the amount and 
quality of data received during the comment period.
    \200\ EPA is reluctant to propose a No. 4 oil specification at 
this time. As noted, EPA has been able to obtain only one sample of 
No. 4 oil. EPA desires more data on genuine samples of this fuel 
before establishing a comparable fuel specification based on No. 4 
fuel oil. As is the case with other types of fuel, if a sufficient 
number of samples are obtained, a No. 4 fuel oil comparable fuel 
specification may be promulgated.
---------------------------------------------------------------------------

    EPA envisions that individual fuel specification(s) could be 
implemented in one of two ways under this approach. First, a facility 
could use any of the individual benchmark specifications, without 
regard to what fuel it currently burns. This approach would provide 
flexibility for the facility in choosing which specification to use. 
Although this approach could allow higher emissions of certain toxic 
compounds at the particular site than would be the case if they burned 
their normal fuel(s), overall (total) emissions of hazardous 
constituents may be lower since a comparable fuel is unlikely to have 
high levels of all constituents. In addition, the amounts of excluded 
waste may well be small relative to the quantity of fossil fuels burned 
annually.

    The second approach is to link the comparable fuel specification to 
the type of fuel burned at the facility and being displaced by the 
comparable fuel. In this case, if a facility burns only No. 2 fuel oil, 
it could only use the No. 2 fuel oil comparable fuel specification to 
establish whether its current waste stream is a comparable fuel. 
Implementation issues include the following: what specification would 
apply if a facility uses a gas or solid fuel, and what is the degree of 
inflexibility introduced?
    EPA prefers the first implementation approach, but invites comment 
on whether a single fuel should be used to base a comparable fuel 
specification and if so, which implementation should be adopted.
2. A Composite Fuel as the Benchmark
    One issue associated with the single fuel specification approach is 
that

[[Page 17464]]

gasoline has relatively high levels of volatile organic compounds while 
No. 6 fuel oil has higher levels of semivolatile organic compounds and 
metals. If a potential comparable fuel were to have a volatile organic 
constituent concentration below the gasoline specification but higher 
than the others, and a particular metal concentration lower than the 
No. 6 fuel oil specification but higher than gasoline, it would not be 
a comparable fuel since it meets no single specification entirely. 
Therefore, EPA is concerned that establishing specifications under this 
option would limit the utility of the exclusion.
    To address this issue, one option is to use a composite approach to 
setting the comparable fuel specification. In this option, EPA would 
use a variety of liquid fuels from which certain compounds would be 
selected to derive the complete specification.
    EPA determined composite fuel specifications for this proposal by 
compositing the data from all fuels analyzed (gasoline and the three 
fuel oils individually). Compositing all the fuels has the advantage 
that it may better reflect the range of fuel choices and potential for 
fuel-switching available nationally to burners. A facility would be 
allowed to use the composite fuel specification regardless of which 
fuel(s) it burns.
    One technical issue is that EPA has different number of samples for 
each fuel type. Therefore, the fuel with the largest number of samples 
would dominate the composite database. To address this issue, EPA's 
statistical analysis ``normalizes'' the number of samples, i.e., treat 
each fuel type in the composite equally without regard to the number of 
samples taken.
    The Agency has evaluated establishing a composite specification 
using: (1) the 90th percentile aggregate values for the benchmark 
fuels; and (2) the 50th percentile aggregate values for the benchmark 
fuels. Under either approach, high gasoline volatile organic nondetects 
would be omitted from the analysis.
    The 90th percentile approach has the virtue of being representative 
of a range of fuels that are burned nationally in combustion devices. 
It also provides maximum flexibility for the regulated community. 
However, the 90th percentile composite approach does allow for higher 
amounts of toxic constituents than other approaches EPA is considering. 
As a practical matter, though, no excluded fuel is likely to contain 
constituent levels at or near all of the 90th percentile composite 
specification level. EPA invites comment on this issue.
    The 50th percentile approach ensures the comparable fuel 
specification is representative of a range of benchmark fuels commonly 
burned at combustion devices, perhaps even more so than the 90th 
percentile approach since it better represents an ``average'' level for 
fuels in general. It also provides flexibility for the regulated 
community, though the specification levels (and potentially the 
usefulness) would be lower than those resulting from the 90th 
percentile approach. If facilities indeed are likely to have at least 
several constituents near the 90th percentile composite levels, a 50th 
percentile composite would be more restrictive and less useful than the 
90th percentile composite approach.
    EPA seeks comments on whether a composite of fuels should be used 
to base a comparable fuel specification and, if so, whether a 90th or 
50th percentile approach would be more appropriate. Further, the Agency 
seeks comment on whether the exclusion should be based on a suite of 
specifications comprised of the individual benchmark fuel-based 
specifications plus a composite specification. Under this approach the 
generator could select any specification in the suite as the basis for 
the exclusion.
3. Waste Minimization Approaches
    By proposing this comparable fuels exemption the Agency does not 
wish to discourage pollution prevention/waste minimization 
opportunities to reduce or eliminate the generation of wastes in favor 
of burning wastes as comparable fuels. EPA solicits comments on the 
effect of today's comparable fuels proposal on facilities' efforts to 
promote source reduction and environmentally sound recycling (which 
does not include burning for energy recovery as a form of recycling in 
the RCRA waste management hierarchy.)

D. Comparable Fuel Specification

    In this section, EPA will outline the five specifications discussed 
above: gasoline, No. 2 fuel oil, No. 6 fuel oil, composite 50th 
percentile values, and composite 90th percentile values. For reasons 
stated above, the individual fuel specifications were based on the 90th 
percentile values. EPA is not proposing any particular approach at this 
time, but invites comments on which approach(es) should be promulgated 
in a final rule. EPA is also presenting the results of the No. 4 fuel 
oil sample for comparison.
1. Hazardous Constituent Specifications
    a. Gasoline Specification. The gasoline-based specification is 
presented in Table 1 of the appendix to this preamble. As stated above, 
gasoline contains more volatile organic compounds (such as benzene and 
toluene) than the other fuels. This results in detection limits for 
volatile organic compounds an order of magnitude higher than the other 
fuel specifications. EPA believes analysis of comparable fuels will 
more likely result in detection limits much lower than gasoline and 
similar to those associated with analysis of fuel oils. To address this 
issue, EPA has performed an analysis of a fuel oil-only composite (one 
which does not include gasoline in the composite) at the 90th 
percentile to use as a surrogate for the volatile organic gasoline non-
detect values. Those values from the fuel oil-only composite are 
presented as the volatile organic nondetect values in Table 1. EPA 
invites comment on whether the approach of substituting fuel oil-only 
volatile organic nondetect values in lieu of those values for gasoline 
is appropriate.
    b. Number 2 Fuel Oil Specification. The No. 2 fuel oil-based 
specification is presented in Table 2 of the appendix to this preamble. 
As suggested above, No. 2 fuel oil contains more volatile organic 
compounds than the other fuel oils, but less than gasoline. In 
addition, its metal concentrations are lower than the other fuel oils, 
but more than gasoline.
    c. Number 4 Fuel Oil Specification. The No. 4 fuel oil-based 
specification is presented in Table 3 of the appendix. It follows a 
similar trend, having fewer organic constituents than those previous 
described, but more metals.
    However, this specification is based on only one sample. The Agency 
is concerned that one sample may not be representative of true No. 4 
fuel oil. As a result, EPA believes that we will not be able to 
promulgate a No. 4 fuel oil specification unless more data is received 
during the comment period.
    d. Number 6 Fuel Oil Specification. The No. 6 fuel oil-based 
specification is presented in Table 4 of the appendix.
    e. Composite Fuel Specifications. Two alternative composite fuel 
specifications are presented in Tables 5 and 6 of the appendix. Table 5 
presents a specification based on the aggregate 50th percentile values 
for the benchmark fuels, and Table 6 presents a specification based on 
the aggregate 90th percentile values of the benchmark fuels.

[[Page 17465]]

    As was the case with the gasoline specification, volatile organic 
detection limits for gasoline are quite large. For this reason, EPA is 
relying on surrogate values for volatile organic detection limits, one 
based on the detection limits from a fuel oil-only composite. For the 
50th percentile composite fuel specification, the 50th percentile fuel 
oil-only volatile organic nondetect values were used. The 90th 
percentile composite fuel specification was handled similarly, using 
the 90th percentile volatile organic nondetect values from the fuel 
oil-only composite. See the discussion for the gasoline sample for 
EPA's concerns regarding gasoline's high detection limits.
2. Physical Specifications (Flash Point and Kinematic Viscosity)
    Alternative physical specifications for the options evaluated are 
presented collectively in Tables 7 and 8 of the appendix. Table 7 
presents the results of the analyses EPA conducted. Table 8 presents an 
alternate approach, using the requirements for viscosity and flash 
point for fuel oil specified by ASTM. Physical specifications for 
viscosity and flash point for gasoline are not required by ASTM, but 
their upper and lower limits, respectively, are available from other 
reference sources.
    When considering a composite physical specifications using the 
reference values presented in Table 8, EPA believes it is appropriate 
to use the second highest viscosity and second lowest flash point as 
the specifications. This would have the effect of not considering the 
extremes, No. 6 fuel oil viscosity (50.0 cSt at 100 deg.C) and gasoline 
flash point (-42 deg.C), and using as the specification the viscosity 
of No. 4 fuel oil (24.0 cSt at 40 deg.C) and the flash point of No. 2 
fuel oil (38 deg.C). EPA believes this approach will result in 
specifications which are representative of comparable fuels and the 
fossil fuels they displace, and ensure adequate safety during 
transportation and storage.
    Subsection A.2.b. discusses the proposed minimum heating value of 
11,500 J/g (5,000 BTU/lbm).

E. Exclusion of Synthesis Gas Fuel

    EPA is also proposing to exclude from the definition of solid waste 
(and, therefore regulation as hazardous waste) a particular type of 
hazardous waste-derived fuel, namely a type of synthesis gas 
(``syngas'') meeting particular, stringent specifications. The Agency 
believes that many fuels produced from hazardous wastes are more waste-
like than fuel- or product-like, and must be regulated as such. We are 
aware, however, of certain fuels and products produced from hazardous 
waste that are more appropriately classified and managed as products 
rather than wastes. EPA believes that syngas meeting the requirements 
of the proposed exclusion is such a material. Syngas is a commercial 
product which has important uses in industry as both a feedstock and 
commercial fuel, and it may be used as both a feedstock and commercial 
fuel at a manufacturing facility. The Agency is therefore proposing 
this exclusion to clarify the distinction between syngas products 
meeting these stringent specifications and hazardous wastes and other 
waste-derived fuels. The Agency believes it is useful to provide a 
conditional exclusion for these particular fuels, possibly before 
promulgating the broader rule being proposed today. This is because, 
although there may be much debate about the generic comparable fuel 
specification levels discussed above, the syngas at issue here appears 
to be well within the bounds of what would be excluded, whatever the 
final rule levels may actually be for other comparable fuels.
    The proposal applies to syngas that results from thermal reaction 
of hazardous wastes which is optimized to both break organic bonds and 
reformulate the organics into hydrogen gas (H2) and carbon monoxide 
(CO). This process is more similar to a chemical reaction, rather than 
to combustion. The process is optimized to produce an end-product, 
rather than merely to destroy organic matter.
    EPA is aware of one such process, proposed to be operated by Molten 
Metals Technology (MMT). MMT intends to operate a catalytic extraction 
process (CEP) unit that generates certain gas streams from the thermal 
reaction of various hazardous wastes, including chlorinated hazardous 
wastes. See letter of July 21, 1995, from Molten Metal Technology to 
EPA. This letter and other information on the MMT process are in the 
docket for today's proposed rule. MMT claims that the syngas generated 
by the processes has legitimate fuel value (i.e., 6,000 to 7,000 Btu/
lb), has a chlorine level of 1 ppmv or less, and does not contain 
hazardous compounds at higher than parts per billion levels. Thus, this 
syngas possesses standard product indicia in the form of fuel value 
plus being the output of a process designed to optimize these 
properties, and the syngas product does not contain hazardous 
constituents at levels higher than those present in fossil fuel.
    To ensure that any excluded syngas meets these low levels of 
hazardous compounds relative to levels in fossil fuels in order to be 
excluded from the definition as a solid waste, the Agency is proposing 
the following syngas specifications:

--Minimum Btu value of 5,000 Btu/lb;
--Less than 1 ppmv 202 of each hazardous constituent listed in 
Appendix VIII of Part 261 (that could reasonably be expected to be in 
the gas), except the limit for hydrogen sulfide is 10 ppmv;
---------------------------------------------------------------------------

    \202\ All specification levels would be documented at normal 
temperature and pressure of the gas at the point that the exclusion 
is claimed.
---------------------------------------------------------------------------

--Less than 1 ppmv of total chlorine; and
--Less than 1 ppmv of total nitrogen, other than diatomic nitrogen 
(N2).
EPA seeks comment on whether there are other hazardous waste-derived 
synthesis gas fuels (i.e., other than MMT's) that meet the criteria for 
this proposed exclusion.
    We also note that conditions imposed for exclusion of syngas fuels 
in no way precludes the use of syngas as an ingredient in 
manufacturing, which is evaluated under a different set of criteria, 
when the syngas is produced from hazardous waste. In other words, if 
the syngas were to be used as either a product in manufacturing or 
burned as a fuel, it would be excluded as a product when it met the 
criteria for use as a product and was used for that purpose and 
excluded as a fuel when burned.
    If EPA adopts this exclusion for syngas fuel, we believe that the 
implementation procedures for the generic comparable fuel exclusion 
discussed subsequently in Section F would also be appropriate for 
syngas. This includes requirements for the syngas producer to notify 
the Regional Administrator that an excluded fuel is produced, a 
certification that the syngas meets the exclusion specification levels, 
and sampling and analysis requirements. EPA invites comment on these 
implementation procedures for syngases and whether any of these 
procedures should be modified to address any unique characteristics of 
syngases.
    Finally, we note that in Section F below we discuss whether the 
burning of hazardous waste excluded under the generic comparable fuel 
exclusion should be restricted only to stationary sources either with 
air permits or that otherwise have their air emissions regulated by a 
federal, state, or local entity. We specifically request comment on 
whether this restriction would also be appropriate for excluded syngas. 
Given that the Agency may undertake final rulemaking to provide an

[[Page 17466]]

exclusion for syngas before promulgating a generic exclusion for 
comparable fuels, however, we request comment on whether more 
restrictive requirements on burning excluded syngas would be 
appropriate to minimize concern about burning a hazardous waste-derived 
gas. For example, the exclusion could be limited to syngas which is 
burned in an industrial boiler, industrial furnace (as defined in 40 
CFR 260.10) or incinerator. We note that these units would not 
necessarily have to be RCRA Subtitle C units.

F. Implementation of the Exclusion

    The implementation scheme described here is adapted from the 
current used oil management system and is tailored to the particular 
characteristics of the comparable fuel universe.203 It provides 
for one-time notification and certification, sampling and analysis, and 
recordkeeping requirements. Other issues addressed include blending, 
ensuring that the comparable fuel is burned, and treatment to meet the 
specification.
---------------------------------------------------------------------------

    \203\ Note that used oil has its own separate management system, 
as allowed under RCRA, tailored to the unique characteristics of 
used oil recycling practices. The comparable fuel exclusion proposed 
today would not apply to used oil because it is adequately and 
appropriately managed under its own tailored system. Used oil will 
still be managed under 40 CFR Part 279. This proposal in no way 
reopens the used oil specification or management structure in 40 CFR 
Part 279.
---------------------------------------------------------------------------

1. Notification and Certification
    EPA proposes that a generator (or syngas producer 204) who 
claims that a (currently defined) hazardous waste meets the 
specification for exclusion must submit a one-time notification and 
certification to the Regional Administrator. The notification would 
state that the generator manages a comparable fuel and certifies 
(through a responsible company official) that the generator is in 
compliance with the conditions of the exclusion regarding sampling and 
analysis, recordkeeping, blending, and ultimate use of the waste as a 
fuel. EPA understands that a ``generator'' may be a company with 
multiple facilities. For this reason, a single company would be allowed 
to submit one notification, but must specify at what facilities the 
comparable fuels notification applies. All other provisions apply to 
each stream at the point of generation.
---------------------------------------------------------------------------

    \204\ Requirements applicable to the generator of an excluded 
fuel would also apply to producers of excluded syngas.
---------------------------------------------------------------------------

2. Sampling and Analysis
    EPA believes it is appropriate that the generator document by 
sampling and analysis that the hazardous waste meets the specification. 
Until such documentation is obtained, the waste would not be excluded. 
Waste analysis rules for TSDFs would apply to comparable fuel 
generators. Consequently, generators would implement a comparable fuels 
analysis plan.
    The sampling and analytical procedures for determining that the 
waste meets the specification must be documented in a comparable fuels 
analysis plan. The comparable fuel analysis plan would involve sampling 
and analyzing for all Appendix VIII constituents initially and at least 
every year thereafter for constituents that the generator could have 
reason to believe are present in the comparable fuel. EPA specifically 
invites comment on whether to allow a generator to use process 
knowledge to determine what compounds to sample and analyze for during 
the first analysis, as well.
    The generator would use current EPA guidance for developing waste 
analysis plans to derive their comparable fuel analyze plan. This will 
ensure that generators sample and analysis as often as necessary, i.e., 
more frequently than every year, for constituents present in the fuel 
to ensure that excluded waste meets the specification.
    Analytical methods provided by SW-846 must be used, unless written 
approval is obtained from the Regional Administrator to use an 
equivalent method. EPA invites comment on establishing a procedure 
similar to Part 63, Appendix A, Method 301 to validate alternate 
analytical methods. EPA also invites comment on whether to limit the 
Agency's time to approve an equivalent method. In this case, the 
Regional Administrator would have a set period of time, such as 60 
days, to respond to the request. If an approval is not received within 
60 days, the alternative method is considered approved. If the Regional 
Administrator later rejects the method, the rejection would only 
pertain to analyses conducted after the rejection of the method.
3. Use as a Fuel
    An integral part of the comparable fuel exclusion is that the fuel 
must be burned. To ensure that the comparable fuel is burned, the 
person who claims the exclusion must either:

--Burn the comparable fuel on-site; or
--Ship the waste off-site to a person who in turn burns the comparable 
fuel.
This provision would not allow any party to manage the fuel other than 
those who generate or burn the fuel (and other than transportation 
related handling). EPA is reluctant to allow persons other than the 
generator and the burner to manage the comparable fuel because it would 
likely be too difficult to ensure that the excluded fuel meets the 
specification and is burned. We invite comment on how to allow third 
party intermediaries, such as fuel blenders, to handle an excluded 
comparable fuel without precipitating serious enforcement and 
implementation difficulties.
    Additionally, EPA is concerned that comparable fuel shipped 
directly to an off-site burner may not in fact be burned. Therefore, 
EPA invites comment on whether, for off-site shipments to a burner, the 
following information should be retained in the record for each 
shipment:

--Name and address of the receiving facility;
--Cross-reference to a certification from the facility certifying that 
the comparable fuel will be burned;
--Quantity of excluded waste shipped;
--Date of shipment; and
--A cross-reference to the analyses performed to determine that the 
waste meets the specification.

A comparable fuel which is not burned remains a hazardous waste and is 
subject to regulation cradle-to-grave.205 This documentation would 
provide a paper trail to ensure that the comparable fuel is burned.
---------------------------------------------------------------------------

    \205\ Note that the only disposal method for a comparable fuel 
is burning. Any disposal method other than burning is a RCRA 
violation, unless the comparable fuel is properly managed as a 
hazardous waste.
---------------------------------------------------------------------------

    EPA invites comment on whether the burning of a comparable fuel 
should be restricted to only stationary sources either with air permits 
or that otherwise have their air emissions regulated by a federal, 
state, or local entity. EPA's primary concern is that excluded fuel may 
be burned in unregulated combustion devices. EPA believes that 
unregulated burners may be unaware of or unprepared to handle many 
unique issues related to fuels other than fossil fuels. In addition, 
EPA invites comment on whether comparable fuels should be allowed for 
use in sources other than stationary sources, i.e., mobile sources (on- 
and off-road automobiles, trucks, and engines) and small engines.
4. Blending To Meet the Specification
    The issue of whether to allow blending to meet the comparable fuel 
specification also needs to be addressed.

[[Page 17467]]

One alternative is to exclude only those comparable fuels that meet the 
specification as generated and which are destined for burning. The 
facilities would be required to demonstrate, for compliance purposes, 
that the waste as generated meets the specification and to certify that 
the waste is destined for burning.
    If blending to lower the concentrations of hazardous constituents 
in a waste were allowed to meet the specification, EPA believes that a 
very extensive compliance and enforcement system would have to be 
instituted to ensure that blending was done properly (with any 
necessary storage and treatment permits) and that the resultant mixture 
meets the specification continually. This alternative appears to 
warrant a degree of oversight that may be infeasible from the industry 
viewpoint and unworkable from the Agency's viewpoint. EPA is also 
investigating whether blending removes the incentive for facilities to 
engage in source reduction and recycling of waste. Finally, this 
alternative raises the issue of whether blending is simply a form of 
prohibited or objectionable dilution that could result in an overall 
increase in environmental loading of toxic, persistent, or 
bioaccumulative substances.
    Complicating this issue is the fact that blending to lower 
hazardous constituent concentrations in used oil is allowed. (40 CFR 
279.50(a).) However, EPA believes it is appropriate to deviate from the 
approach for used oil in this case. Used oil is better defined and 
understood in its origins and use than currently defined hazardous 
wastes. Used crankcase oil is a petroleum product analogous to a thick 
fuel with enriched metal concentrations due to its use for lubricating 
metal-bearing parts in situations of tight tolerance. In the case of 
used oil, blending a thick fuel enriched with metals with a thinner 
fuel with low concentrations of metals is appropriate since the 
resulting mixture would be wholly a petroleum product with similar 
levels of metals as other petroleum fuels.
    Comparable fuels, however, differ substantially from used oil in 
both the nature of materials to which the exclusion pertains and the 
scope of the exclusion. A comparable fuel is presently defined as a 
hazardous waste and is unlikely to be a petroleum distillate. The issue 
of toxic organic constituents is important for comparable fuels due to 
the diversity of processes and process ingredients from which potential 
comparable fuels may result. This is not relevant for the used oil 
rules since they deal with the post-use material stemming from a highly 
consistent and well known petroleum distillate. Therefore, blending 
used oil would result in a more predictable mixture, one which would be 
expected to contain the same organic compounds in varying 
concentrations. The same cannot be said for the large variety of 
potential comparable fuels, which can vary significantly in the 
constituents present.
    The issue of metals in a comparable fuel is similarly different 
from the case of used oil. While used oil does contain enriched levels 
of metals relative to virgin oil or petroleum fuels, those levels are 
greatly understood (relative to hazardous waste in general) due to 
their use in only one process, the lubrication of metal-bearing parts. 
Therefore, there is essentially a real-world limit to the amount and 
type of metal that could be entrained in a used oil, so blending to 
meet metal specifications is more appropriate. In the case of 
comparable fuels if there were no prohibition on blending to meet 
constituent specifications, a generator would be allowed to take a 
predominantly metal waste, blend it into a fuel to levels lower than 
the constituent specification levels, and (through pure dilution) meet 
the exclusion. For these reasons, EPA believes the specially tailored 
used oil program does not provide a satisfactory model to use for 
addressing the issue of blending potential comparable fuels.
    We also note that the LDR program specifically prohibits dilution 
as a form of treatment. (40 CFR 268.3.) Allowing blending to meet the 
specification may, in effect, allow dilution as a form of treatment 
contrary to the LDR prohibition for these hazardous wastes. For these 
reasons, EPA desires to stay consistent with other rules and policies 
and not allow blending to meet the comparable fuels specification.
    Similarly, EPA proposes that the specification for heating value be 
met on an as-generated basis as well. In other words, blending would 
not be allowed to meet the heating value specification. If the Agency 
were to allow blending to meet the heating value specification, wastes 
with no heating value could be blended with high heating value fossil 
fuels and meet the comparable fuel heating value specification. EPA 
does not believe this approach can be justified, allowing a waste which 
as generated has little or no heating value to be a comparable fuel. 
Therefore, we propose that heating value be met on an as generated 
basis.
    For these reasons, EPA is proposing that the comparable fuel 
constituent and heating value specifications be met on an ``as 
generated'' basis, and that blending to meet the constituent and 
heating value specifications not be allowed. However, if the 
constituent and heating value specifications have been met as 
generated, EPA believes it may be appropriate for a comparable fuel to 
be treated like any other fuel and allow it to be blended after the 
constituent and heating value specifications have been met. This 
includes blending for the purposes of meeting other physical 
specifications (flash point and viscosity), pH neutralization, etc.
    After blending, generators would have to retest the prospective 
comparable fuel to ensure that blending did not increase the levels of 
constituents to above the specification levels or decrease it to below 
the heating value requirement. If the waste were blended with a clean 
fossil fuel, such as No. 2 fuel oil, it would be sufficient to document 
that the substance the prospective comparable fuel is being blended 
with has lower constituent levels and a higher heating value than the 
comparable fuel specification. If the waste is above constituent 
specifications or below the heating value requirement after blending, 
the waste would not be a comparable fuel.
    EPA invites comment on the issue of blending only to meet the 
physical specifications, flash point and kinematic viscosity.
5. Treatment To Meet the Specification
    It is possible, as a technical matter, for hazardous wastes to 
undergo treatment that destroys or removes hazardous constituents and 
thereby produce a comparable fuel. Likewise, it is possible to treat a 
waste such that the heating value of the waste is increased. For 
example, distillation could remove certain organic constituents from 
the waste matrix, thereby allowing the treated waste to meet the 
comparable fuel specification. Similarly, decanting to decrease the 
water concentration of the waste stream would increase the heating 
value of the waste by concentrating those compounds which are burned. 
The issue discussed here is whether such processes should be allowed 
under a comparable fuel regime, and if so, under what circumstances. 
The Agency is proposing to allow treatment under limited circumstances.
    The Agency's concern about allowing such treatment is that it could 
increase the incentive and opportunity for impermissible blending or 
otherwise fraudulent treatment. Thus, at the least, EPA would seek to 
set up controls to reduce the possibility of such practices

[[Page 17468]]

if treatment were allowed. This might be done by requiring treaters to 
document that the comparable fuel specification is being satisfied 
through treatment that destroys or removes hazardous constituents and/
or increases heating value by removing constituents from the waste, not 
through blending or other dilution-type activities. Second, where the 
treater has a RCRA permit for the storage/treatment activity (i.e., 
treatment of hazardous waste conducted in any unit except a 90-day 
generator unit not subject to permitting requirements under 
Sec. 262.34), the rule could authorize permit writers to add conditions 
to the permit to assure the integrity of the permitted process. Such 
conditions could take the form of extra conditions on the treatment 
process, conditions on the wastes which could be treated to produce 
comparable fuels, and additional sampling and analysis of both incoming 
wastes and outgoing comparable fuels. The Agency solicits comment on 
what limitations or conditions should be imposed on treatment 
activities and whether and how to adapt such limitations or conditions 
to the non-permitted context of 90-day generator units.
    Finally, it should be noted that if hazardous wastes are treated to 
produce comparable fuels, only the comparable fuel would be excluded 
from RCRA subtitle C regulation. The hazardous wastes would be 
regulated from point of generation until a comparable fuel is produced, 
so that generation, transport, storage, and treatment of the waste 
until production of the comparable fuel would remain subject to the 
applicable subtitle C rules. Also any residuals resulting from 
treatment remain hazardous wastes as a result of the derived-from rule.
6. Recordkeeping
    It is proposed that documentation pertaining to verification that 
the waste meets the comparable fuel specification and the information 
on shipments be retained for three years. The sampling and analysis 
plan and all revisions to the plan since its inception would be 
retained for as long as the person claims to manage excluded waste, 
plus three years. Certifications from burners (if required in the final 
rule) would be retained for as long as the burner is shipped comparable 
fuels, plus three years.
    The generator would retain the records supporting its claim for the 
exemption. For comparable fuels which are not blended, the records that 
must be retained are the as generated results. For comparable fuels 
which are blended to meet the flash point and/or kinematic viscosity 
specifications, the records which must be retained are those after 
blending.
7. Small Business Considerations: Inherently Comparable Fuel
    Small businesses may, hypothetically, generate wastes (such as 
mineral spirits used to clean automotive parts) that could meet a 
comparable fuel specification. However, the Agency is concerned that 
the proposed implementation scheme for the comparable fuel exclusion 
may be overly burdensome to small businesses because of the small 
volume of waste each business may generate. EPA requests data on 
whether categories of high volume inherently comparable fuel from a 
large number of small generators exist. If so, EPA would consider 
providing an exclusion for these fuels in the final rule. For these 
fuels to be excluded, the Agency would need constituent data from 
various small generators indicating that these wastes would meet the 
comparable fuel exclusion levels on a routine basis.
    If an inherently comparable fuel exclusion were promulgated in the 
final rule, the Agency would promulgate a petitioning process whereby 
classes of generators could document that a specific type of waste is 
virtually always likely to meet the comparable fuel specification. If 
the Agency granted the petition through rulemaking, such waste would be 
classified as inherently comparable fuel. As such, the generator would 
not be subject to the proposed implementation requirements for the 
comparable fuel exclusion: notification, sampling and analysis, and 
recordkeeping. In addition, such inherently comparable fuel could be 
blended, treated, and shipped off-site without restriction given that 
it would be excluded from regulation as generated.
    EPA invites comment on whether high volumes of comparable fuel is 
generated from a large number of small generators. If so, the Agency 
requires data on whether this approach provides relief to small 
businesses while ensuring protection of human health and the 
environment. In addition, EPA invites analytical data supporting 
classification of particular wastes as inherently comparable fuel. The 
Agency would provide notice and request comment on such data prior to 
making a final determination that the waste is inherently comparable 
fuel.

G. Transportation and Storage

    Waste derived fuels can pose risks during transportation and 
storage, not just when burned. For instance, comparable fuels could be 
reactive and corrosive (virgin fossil fuels are neither), more volatile 
than fossil fuels, or have other special properties affecting handling 
and storage. The Agency believes we can exempt comparable fuels from 
RCRA storage and transportation requirements and therefore rely on the 
storage and transportation regulations of other federal and state 
agencies. However, the affected industries may have more direct 
knowledge of how these requirements actually affect shipments and 
storage of the potential fuels, particularly with respect to the extent 
of state regulatory controls. We are therefore asking commenters to 
give EPA information on the adequacy of DOT and OSHA requirements 
related to storage and transportation, particularly with respect to 
whether a combustion facility (including an industrial boiler) will be 
on proper notice about the nature and behavior of the comparable fuel 
to allow for safe handling and burning.
    In this regard, EPA believes it is appropriate to set a minimum 
flash point for comparable fuels. (See section A.2. for a general 
discussion concerning the Comparable Fuels Specification.) The flash 
point is defined as the minimum temperature at which a substance gives 
off enough flammable vapors which in contact with a spark or flame will 
ignite. Setting a minimum flash point would ensure that under ambient 
conditions the comparable fuel would not ignite during transportation 
and storage.
    A shortcoming of this approach is that a purchaser or other off-
site facility may desire a comparable fuel with a flash point lower 
than the comparable fuel specified flash point. EPA does not wish to 
preclude low flash point comparable fuels from the exemption. 
Therefore, the Agency is inclined to allow some waiver of the minimum 
flash point specification under certain circumstances.
    EPA is proposing to allow low flash point comparable fuels if there 
is some notice to intermediate carriers and the ultimate user of what 
the flash point of this comparable fuel is. To do this, EPA needs to be 
assured that these low flash point comparable fuels can be stored, 
handled, and transported safely. EPA is inclined to believe current DOT 
and OSHA requirements for transportation and storage of hazardous or 
combustible liquids are adequate for this purpose, but we specifically 
seek comment on this issue.

[[Page 17469]]

H. Speculative Accumulation

    EPA is also proposing that comparable fuels remain subject to the 
speculative accumulation test found in Sec. 261.2(c)(4). This means 
that persons generating or burning comparable fuels must actually put a 
given volume of the fuel to its intended use during a one-year period, 
namely 75 per cent of what is on hand at the beginning of each calendar 
year commencing on January 1. See the definition of ``accumulated 
speculatively'' in Sec. 261.1(c)(8). (The rules also provide for 
variances to accommodate circumstances where such turnover is not 
legitimately practical. Sec. 260.31(a).) EPA applies this test to other 
similar exclusions of recycled secondary materials in the rules (see 
Sec. 261.2(e)(2)(iii).) This is because over accumulation of hazardous 
waste-derived recyclables has led to many of the most severe hazardous 
waste damage incidents. See 50 FR at 658-61 and 634-37 (January 4, 
1985). There is no formal recordkeeping requirement associated with the 
speculative accumulation test, but the burden of proof is on the person 
claiming the exclusion to show that the test has been satisfied. 
Sec. 261.2(f) and 50 FR at 636-37.

I. Regulatory Impacts

    EPA also requests data from the regulatory community concerning the 
regulatory impacts of this proposed comparable fuel exclusion. Impact 
data includes the quantity of waste which would be excluded (by weight) 
and the cost savings as a result of the exclusion. Based on the data 
submitted, EPA will develop a full regulatory impact assessment during 
the final rulemaking.

J. CMA Clean Fuel Proposal

    The Chemical Manufacturers Association (CMA) submitted a proposal 
to exempt certain ``clean'' liquid wastes from RCRA regulation 
206. Unlike EPA's benchmark-based comparable fuel proposal, the 
CMA approach would establish clean fuel specifications for mercury, 
LVM, and SVM metals based on the technology-based MACT emission 
standards proposed today. For mercury, CMA calculated the maximum feed 
rate the facility would be allowed if it had a given gas flowrate, no 
mercury control, and yet complied with today's proposed standards. This 
would establish the maximum mercury concentration of the CMA ``clean 
fuel'' specification. Limits would be established for LVM and SVM 
metals in a similar fashion. For chlorine, CMA presented a 
specification level based on the concentration of chlorine found in 
coal. Limits for ash content would be derived from No. 4 fuel oil.
---------------------------------------------------------------------------

    \206\ See Revised CMA Proposal for Clean Waste Fuels Exemption 
to RCRA dated March 1, 1996.
---------------------------------------------------------------------------

    The CMA proposal also appears to rely solely on adequate thermal 
destruction of the organics to control potential organic contamination 
and risks therefrom. Combustion would be limited to on-site boilers or 
boilers owned and operated by the clean fuel generator, where these 
boilers meet a 100 ppmv hourly rolling average CO limit.
    CMA's clean fuel proposal would also establish limits on physical 
specifications. The heating value of a CMA clean fuel would have to be 
at least 5,000 BTU/lb, viscosity would have to be less that 26.4, and 
the clean fuel must be a liquid.
    Acutely hazardous wastes 207 would not be eligible for CMA's 
proposed clean fuel exemption, nor would dioxin-listed wastes 
(hazardous waste numbers F020, F021, F022, F023, F026, F028.)
---------------------------------------------------------------------------

    \207\ That is, discarded commercial chemical products listed in 
Sec. 261.33 (``P'' listed wastes), and acutely hazardous (those with 
``H'' hazard codes) wastes listed in Secs. 261.31 and 261.32 
(hazardous wastes from non-specific and specific sources, ``F'' and 
``K'' listed wastes, respectively.)
---------------------------------------------------------------------------

    EPA invites comment on CMA's proposed ``clean fuels'' 
specification. Specifically, EPA requests commentors address the 
following issues and questions:

--Is reliance on the technology-based MACT emission standards approach 
appropriate for establishing a clean fuel exemption under RCRA, either 
with or without restrictions on the type of device that can be used to 
burn the clean fuel? How does EPA justify not establishing specific 
constituent limits for the other five RCRA metals?
--Does a CO limit alone ensure adequate destruction of toxic organics 
in a clean fuel scenario? Would additional controls, such as an HC 
limit, limits on inlet temperature to a dry PM APCD, DRE testing, and 
site-specific risk assessment also be appropriate?
--Does CMA's proposal adequately address new facilities? Would it be 
appropriate to allow off-site shipment to a facility not owned by the 
generator if the generator owns no combustion device in the vicinity? 
If so, how would EPA be able to ensure compliance regarding the CO 
emissions (and possibly other testing and operational conditions) of a 
combustion device not owned by the generator?
--Should CMA's clean fuel approach be expanded to include gaseous as 
well as liquid fuels?
--Are there wastes other than those identified by CMA (acutely toxic 
and dioxin-listed wastes) which should not be eligible for a ``clean 
fuel'' exemption? If so, what would be the practical impacts of such 
expanded ineligibility?
--Are data available documenting that emissions from burning a ``clean 
fuel'' would not pose a significant risk for the potential combustion 
and management scenarios in which the clean fuel exclusion from RCRA 
might be used?

II. Miscellaneous Revisions to the Existing Rules

    This section provides several miscellaneous revisions to the RCRA 
hazardous waste combustion rules provided by 40 CFR Parts 260-270. We 
note that we are also proposing other revisions to Parts 260-270 that 
would be conforming revisions to ensure that the RCRA rules are 
consistent with similar provisions of the proposed Part 63 rules. Those 
proposed conforming revisions are discussed elsewhere in the preamble.

A. Revisions to the Small Quantity Burner Exemption Under the BIF Rule

    The Agency is proposing to revise the small quantity burner (SQB) 
exemption provided by Sec. 266.108 of the BIF rule because the current 
exemption may not be protective of human health and the environment. 
Under the exemption, BIFs could burn up to the exempt quantities absent 
regulation other than notification and recordkeeping requirements. 
Under a settlement agreement, the environmental petitioners in 
Horsehead Resource Development Company, Inc., v. EPA (No. 91-1221 and 
Consolidated Cases), the Agency must reevaluate whether the small 
quantity burner exemption is sufficiently protective given that the 
Agency did not consider indirect exposure pathways in calculating the 
exemption levels. In addition, the petitioners argued that the 
exemption is inconsistent with the intent of RCRA Sec. 3004(q)(2)(B) 
which specifically allows the Administrator to exempt facilities which 
burn de minimis quantities of hazardous waste because the exemption as 
promulgated would allow sources to burn up to 2,000 gallons of 
hazardous waste per month absent substantive emissions controls. 
Petitioners believe that 2,000 gallons per month is not a de minimis 
quantity.
    EPA attempted to reevaluate exempt quantities considering indirect 
exposure

[[Page 17470]]

pathways for, in particular, emissions of dioxins and furans (D/F). 
Unfortunately, we were not able to adequately predict emission levels 
of D/F for purposes of conducting a generic, national risk assessment 
to back-calculate exempt quantities. We could not effectively predict 
D/F emissions because: (1) There may be little relationship between 
quantity of hazardous waste burned and D/F emissions (i.e., other 
factors may result in high or low D/F emissions); and (2) there are 
several site-specific factors that can affect D/F emissions, including 
combustion efficiency (that is affected by factors such as combustion 
zone temperature, oxygen levels, and residence time in the combustion 
zone), gas temperature at the particulate matter control device, and 
presence of precursors such as PCBs.
    In addition, we found it difficult to identify an appropriate 
indirect exposure scenario for purposes of assessing risk to support a 
generic exemption. We note that to evaluate whether the proposed MACT 
standards met RCRA protectiveness requirements, we analyzed 11 example 
facilities assuming the example facilities emitted HAPs at the 
regulatory option levels. We did not have site-specific stack gas 
properties (e.g., gas flow rate, gas temperature, stack height) and 
exposure information to conduct similar indirect exposure assessments 
for example SQB facilities.
    Given these difficulties, the Agency is proposing to revise the SQB 
exemption to limit exempt quantities to 100 kg/mo (27 gal/mo), which is 
the current exemption level for small quantity generators (SQG) 
provided by Sec. 261.5. We believe that this is appropriate given that 
SQG hazardous waste is already exempt from regulation and thus, may be 
burned absent emission controls. We note, however, that the SQB 
exemption can apply to facilities owned or operated by large quantity 
generators. Thus, under today's proposal, wastes not eligible for the 
SQG exemption could be eligible for the SQB exemption. Nonetheless, we 
believe that 27 gal/mo is a reasonable level for the exemption because 
it is truly a de minimis quantity and such quantities can be burned 
absent emission controls under existing SQG regulations.
    We believe that approximately 200 boilers are currently operating 
under the SQB exemption. Many of these boilers are likely burning 
quantities in excess of 27 gallons/mo, and so would be subject to full 
regulation as a BIF under today's proposal. We note, however, that we 
are also proposing today a comparable fuels exclusion that would 
exclude from the definition of solid and hazardous waste any material 
that meets the proposed comparable fuels specification. Although we 
currently have no information on how many SQBs could use the comparable 
fuels exclusion, some heretofore SQBs are expected to be eligible for 
this proposed exclusion.
    Sources that burn hazardous waste that do not meet the comparable 
fuels specification may determine that it is less expensive to send 
their waste to a commercial burner than comply with the BIF 
regulations. Those sources that choose to continue burning hazardous 
waste would be required to comply with the substantive requirements of 
the BIF rule. Since the BIF rule would subject some of these facilities 
to RCRA regulation for the first time (assuming no other permitted 
units are at the facility), these SQB facilities would be eligible for 
interim status. See 56 FR at 7186 (February 21, 1991) for requirements 
regarding permit modifications, section 3010 notifications, and Part A 
permit applications. Such sources would also be required to submit a 
certification of precompliance (required by Sec. 266.103(b)) within 6 
months of the date of publication of the final rule in the Federal 
Register, and a certification of compliance (required by 
Sec. 266.103(c)) within 18 months of the date of publication of the 
final rule.

B. The Waiver of the PM Standard Under the Low Risk Waste Exemption of 
the BIF Rule Would Not Be Applicable to HWCs

    Section 266.109 of the BIF rule provides a conditional exemption 
from the destruction and removal efficiency (DRE) standard and the 
particulate matter (PM) emission standard. The DRE standard is waived 
if the owner or operator complies with prescribed procedures to show 
that emissions of toxic organics are not likely to pose a potential 
hazard to human health considering the direct inhalation pathway. The 
PM standard is waived if the DRE standard is waived and the source 
complies with the Tier I or adjusted Tier I feedrate limits for metals.
    We are proposing today to restrict eligibility for the waiver of 
the PM standard to BIFs other than cement and lightweight aggregate 
kilns. This is because: (1) Compliance assurance with the proposed MACT 
standards for D/F, SVM, and LVM is based on compliance with a CEM-
monitored, site-specific PM emission limit;208 and (2) the 
proposed MACT PM standard would be used to help minimize emissions of 
adsorbed non-D/F organic HAPs. Given that this restriction for cement 
and lightweight aggregate kilns is needed to ensure compliance with the 
proposed MACT standards, the restriction would be effective at the time 
that the kiln begins to comply with the MACT standard (i.e., when the 
source submits the initial notification of compliance).
---------------------------------------------------------------------------

    \208\ Not to exceed the proposed national MACT standard.
---------------------------------------------------------------------------

    Finally, we note that, as a practical matter, we believe that this 
proposed restriction of eligibility for the PM waiver for kilns will 
have little or no effect on the regulated community. We are not aware 
of any cement or lightweight aggregate kilns that both meet the 
conditions for the exemption and have elected or intend to elect to 
request the waiver.
    The Agency solicits comment on the application of waste 
minimization to lower the volume of waste streams fed to combustors so 
that the combustor can meet the proposed revised SQB feed limitations. 
Such reductions might be achieved by meeting the proposed HWIR 
standards and thus removing entire streams from Subtitle C 
requirements. The Agency is particularly interested in technical and 
economic information about commercial or experimental processes to 
reduce stream volume.

C. The ``Low Risk Waste'' Exemption from the Emission Standards 
Provided by the Existing Incinerator Standards Would Be Superseded by 
the MACT Rules

    Section 264.340(c) exempts certain incinerators from the emission 
standards if the hazardous waste burned contains insignificant 
concentrations of Appendix VIII, Part 261, hazardous constituents which 
would reasonably be expected to be in the waste. In implementing this 
provision, the Agency has used various measures of risk potential to 
define ``insignificant'' concentrations. We believe that a risk-based 
waiver is inconsistent with today's proposed technology-based MACT 
standards for incinerators, and in any case could not supersede those 
standards. Thus, we are proposing that this provision no longer be 
applicable to an incinerator at the time it begins complying with the 
MACT standards (i.e., when the initial notification of compliance is 
submitted).
    We also note that Sec. 264.340(b) provides the same exemption from 
emission standards if the hazardous waste burned does not contain any 
(i.e., nondetect levels) of the Appendix VIII constituents. We are 
proposing that this provision also be superseded by the proposed MACT 
standards because: (1) Detection limits may be high for some

[[Page 17471]]

waste matrices; and (2) nontoxic organics in the waste can result in 
emissions of toxic organics under poor combustion conditions or 
conditions favorable to formation of D/F in the post-combustion zone 
(e.g., a PM control device operating at temperatures above 400 deg.F).

D. Bevill Residues

1. Required Testing Frequency for Bevill Residues
    The Agency is proposing to set a minimum sampling and analysis 
frequency for residues derived from the burning or processing of 
hazardous waste in units that may qualify for the Bevill exemption by 
satisfying the requirements of Sec. 266.112 (a) and (b). The Agency 
believes a minimum testing frequency is necessary to prevent large 
quantities of hazardous residues from being managed in an 
environmentally unsound manner.
    Current regulations require that waste derived residue be sampled 
and analyzed ``as often as necessary to determine whether the residue 
generated during each 24-hour period'' meets requirements to qualify 
for the Bevill exemption. Because large volumes of residue are 
generated in any 24-hour period, it is possible that a facility may 
have disposed of the residue after a sample had been taken, but before 
the analysis results are received. The Agency stated in the preamble to 
the BIF regulations (56 FR 42504 (August 27, 1991)) that ``if the waste 
derived residue is sampled and analyzed less often than on a daily 
basis, and subsequent analysis determines that the residue fails the 
test and is fully regulated hazardous waste, the Agency considers all 
residue generated since the previous successful analysis to be fully 
regulated hazardous waste absent documentation otherwise.'' Residue 
generated after the failed test may also be considered hazardous waste 
until the next passing test. The residue disposal area or unit would 
also become subject to Subtitle C requirements.
    In the interest of protecting human health and the environment and 
avoiding the scenarios mentioned above, the Agency is today proposing 
that if a facility elects to sample and analyze less frequently than 
every day, approval must be granted by the Regional Administrator and 
the sampling and analysis frequency used must be based on and justified 
by statistical analysis. The Agency is also proposing that, in the 
event the Regional Administrator approves less than daily sampling at a 
facility, the facility must, at a minimum, sample and analyze its 
residues at least once every month for metals and once every six months 
for other compounds. A more frequent minimum sampling frequency has 
been proposed for metals because of the variability of metal content in 
feed materials and because metals cannot be destroyed in the furnace. 
The proposed sampling frequency will minimize the possibility of large 
volumes of hazardous residues being placed on the land or otherwise 
being stored or disposed of contrary to Subtitle C requirements. The 
Agency does not believe these proposed requirements will unduly burden 
the regulated community and requests comments on this issue.
    The following factors must be considered when determining an 
appropriate sampling frequency:

--Selection of a statistical method and distribution of data (normal or 
log normal distribution)
--Feedrates of wastes and all other feed streams
--Volatility of metals in all feed streams
--Physical form of various feed streams (solid versus liquid)
--Type of feed system
--Levels and types of organic constituents in all feedstreams (for 
example, difficulty of destruction or formation of by-products)
--Levels and types of metals regulated under RCRA, other than those 
regulated by the BIF regulations (for example, selenium)
--Changes in feed streams
--Changes in operating conditions or equipment
--Operating conditions when sampling compared with those when not 
sampling
--Trends in partitioning of metals in fly as compared with bottom ash

    Facilities with a high variability of hazardous constituents in 
their residues should closely examine these factors in deciding upon a 
sampling frequency. Facilities with residues that exhibit little or no 
constituent variability may be able to sample at the minimum frequency, 
pending approval of less than daily sampling by the Regional 
Administrator.
2. Dioxin Testing of Bevill Residues
    a. Regulatory History. Under 40 CFR Sec. 266.112 of the boiler/
industrial furnace (BIF) rule, EPA codified procedures for owners and 
operators of Bevill devices to determine whether their residues retain 
the Bevill exemption when the facilities co-fire or co-process 
hazardous waste fuels along with fossil fuels or normal raw materials. 
These procedures were deemed necessary to ensure that the burning of 
hazardous waste does not alter the residues so that they are no longer 
the ``high volume, low hazard'' materials exempted by the Bevill 
amendment. This test was upheld by the D.C. Circuit in Horsehead 
Resource Development Co. v. Browner, 16 F. 3d 1246 (D.C. Cir. 1994).
    Specifically, 40 CFR Sec. 266.112 requires facilities that claim 
the Bevill exemption for residues from co-burning hazardous waste along 
with Bevill raw materials to conduct sampling and analysis of their 
residues to document that either: (1) Levels of toxic constituents in 
the waste-derived residue are not significantly higher than normal 
(i.e., when not burning hazardous waste) residues; or (2) levels of 
toxic constituents in waste-derived residue do not exceed health-based 
levels specified in the rule. This is commonly referred to as the two-
part Bevill test. The constituents for which analysis must be conducted 
include: (1) Appendix VIII, Part 261, hazardous constituents that could 
reasonably be expected to be in the hazardous waste burned, and that 
are listed in Sec. 268.40 for F039 non-wastewaters (see 59 FR 4982 of 
September 19, 1994); and (2) compounds that the Agency has determined 
are common products of incomplete combustion (i.e., they may be formed 
during combustion of the waste) and have been listed in Appendix VIII 
of Part 266.
    b. Addition of Dioxin/Furan Compounds to the Appendix VIII, Part 
266 Product of Incomplete Combustion List. The Appendix VIII, Part 266 
product of incomplete combustion (PIC) list does not currently include 
polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzo-
furan (PCDF) compounds. In addition, most BIF facilities do not burn 
wastes which could reasonably be expected to contain PCDD/PCDF 
compounds. Thus, few Sec. 266.112 facilities have been analyzing their 
residues on a routine basis for PCDD/PCDF compounds to determine 
whether burning hazardous waste has affected the character of the 
residue.
    EPA believes that it is important to add PCDD/PCDF compounds to the 
PIC list in order to make residue analysis for PCDD/PCDFs a mandatory 
component of the two-part Bevill test. First, dioxin/furan compounds 
are likely to be PICs and, as such, should rightfully be included on 
the PIC list. As described in Chapter 4 of the May 1994 Draft 
Combustion Emissions Technical Resource Document (CETRED), there is a 
considerable body of evidence to show that PCDD/PCDF compounds can be

[[Page 17472]]

formed in the post-combustion regions of boilers, industrial furnaces 
and incinerators, even if no PCDD/PCDF compounds are fed to the 
combustion device. Secondly, the level of dioxins in residues can be 
influenced by hazardous waste burning activities. The October 1994 
Cement Kiln Dust Notice of Data Availability, which augmented the 
December 1993 Report to Congress on Cement Kiln Dust, provided a 
regression analysis to determine the impact of hazardous waste fuel use 
on dioxin and furan concentrations. Every one of the dioxins and furans 
evaluated appeared in significantly higher concentrations in cement 
kiln dust generated by plants that burned hazardous waste fuel in 
comparison with plants that did not burn any hazardous waste fuels. The 
Report concluded that the strength and consistency of this relationship 
for cement kiln dust was striking, and that it provides very strong 
evidence that dioxin and furan concentrations in the dust are 
systematically higher at plants that burn hazardous waste fuel.
    Finally, it is important to note that, where the potential for 
excess risks were identified in the Report, the constituents of concern 
included metals and dioxin/furan compounds. Metals are already covered 
by the two-part test of Sec. 266.112. However, it is equally important 
to include PCDDs/PCDFs in the two-part test to make sure that residues 
from hazardous waste-burning devices continue to meet the high volume, 
low hazard criteria presumed by the Bevill exemption.
    c. Use of Land Disposal Restriction Standards as Interim Limits for 
PCDD/PCDFs. On November 9, 1993, EPA published an interim final rule 
establishing alternate concentration limits for nonmetals to be used 
for the health-based comparison portion of the two-part Bevill test 
(i.e., 40 CFR Sec. 266.112(b)(2)). The alternate levels were based on 
the land disposal restriction (LDR) limits for F039 non-wastewaters 
pending further administrative action to determine whether more 
appropriate health-based levels should be developed. Although the LDR 
limits are not health-based levels, the Agency noted in the preamble 
(58 FR at 59598 (Nov. 9, 1994)) that the technology-based LDR treatment 
limits should serve to identify residues that have the ``low toxicity'' 
attribute that is one of the key bases for the temporary exemption of 
Bevill residues from the definition of hazardous waste. See Horsehead 
Resource Development Co. v. Browner, 16 F. 3d. The Agency also noted 
that the LDR levels are promulgated limits and so have been scrutinized 
and subject to public comment in previous rulemakings.
    As part of today's proposal to add PCDD/PCDF constituents to the 
Appendix VIII, Part 266 PIC list, the Agency would continue the interim 
practice of basing the concentration limits for the health-based 
portion of the two-part Bevill test on the LDR F039 nonwastewater 
levels. The LDR regulation establishes concentration limits of 1 part-
per-billion (ppb) for total HxPCDDs, total HxPCDFs, total PePCDDs, 
total PePCDFs, total TCDDs and total TCDFs. The Agency believes that 
these levels for dioxin/furan compounds will serve as adequate 
screening levels on an interim basis to ensure that residues from 
hazardous waste-burning devices continue to meet the ``low toxicity'' 
attribute presumed by the Bevill exemption.
    The Report to Congress on Cement Kiln Dust provides some support 
for the 1 ppb PCDD/PCDF screening criteria. In baseline risk modeling 
for fifteen case study facilities managing CKD on-site, dioxin/furan 
compounds were not identified as contributors to adverse health effects 
for either direct or indirect exposure pathways (see Report, Exhibit 6-
14). Risk from PCDD/PCDFs only reached levels of concern when the 
Agency performed a sensitivity analysis to examine the change in risks 
that would occur at five baseline facilities based on the hypothetical 
management of CKD containing the highest measured PCDD/PCDF 
concentrations found in EPA's sampling at 11 cement plants. The highest 
concentrations were observed in samples from a cement facility, and 
were at least 2\1/2\ times higher than concentrations observed at any 
other facility. All of the samples from that facility exceeded 1 ppb 
for at least one homolog listed as part of the LDR F039 criteria (i.e., 
total HxPCDDs, total HxPCDFs, total PePCDDs, total PePCDFs, total TCDDs 
or total TCDFs). Thus, the levels which showed potential for adverse 
health effects in the site-specific modeling would be screened by 
application of the 1 ppb criteria listed in the F039 LDR. By 
comparison, none of the samples from facilities other than the above 
facility had any PCDD/PCDF homologs exceeding 1 ppb.
    The Agency is proposing continued use of the LDR levels because it 
does not believe that it is appropriate to establish a more specific 
health-based level for dioxin/furan compounds at this time.209 A 
separate regulatory process is underway which will establish controls 
on management of cement kiln dust (60 FR 7366). Any health-based level 
established in advance of these controlled CKD management standards 
would quickly become obsolete because, at a minimum, the fate and 
transport assumptions would be different. The Agency specifically 
requests comment regarding whether the interim LDR F039 limits for 
PCDD/PCDF constituents are appropriate. Alternatively, the Agency 
requests information regarding an appropriate methodology for 
establishing more specific health-based limits.
---------------------------------------------------------------------------

    \209\ EPA notes that, by establishing LDR exemption levels for 
Bevill residue, the Agency is not suggesting that: (1) the 
technology-based treatment standards are equivalent to, or 
appropriate to use as, health-based limits; or (2) Bevill excluded 
residues should necessarily be subject to the LDR rules. See 58 FR 
at 59603 (November 9, 1994). These issues are the subject of other 
rulemakings.
---------------------------------------------------------------------------

    d. Clarification of Appendix VIII, Part 266 PIC List Applicability. 
There has historically been some confusion regarding whether each of 
the constituents listed on the Appendix VIII, Part 266 list must be a 
mandatory component of the residue testing at every facility, or 
whether a facility could exclude some of the constituents on the list. 
Today, the Agency clarifies that the Appendix VIII, Part 266 list is 
applicable to every facility in its entirety, without exclusion.
3. Application of Derived From Rule to Residues From Hazardous Waste 
Combustion in non-Bevill Boilers and Industrial Furnaces
    As part of a settlement agreement of the lawsuit over the 1991 BIF 
regulations, EPA agreed to reconsider the appropriateness of applying 
the derived from rule to residues from co-processing listed hazardous 
waste fuels and raw materials in non-Bevill boilers and industrial 
furnaces. An example would be an oil-fired boiler burning listed 
hazardous waste fuel and generating emission control dusts or scrubber 
effluents, which dusts or effluents would not be considered to be 
Bevill excluded. If this type of burning occurs in a boiler or furnace 
whose residues are otherwise within the scope of the Bevill amendment, 
the residues remain exempted from subtitle C (i.e. remain exempted by 
virtue of the Bevill amendment) so long as they are not ``significantly 
affected'' by burning hazardous waste. Sec. 266.112. A residue is not 
significantly affected if there is no statistically significant 
increase between baseline, non-hazardous waste-derived residues, or if 
hazardous constituents in the residue do not exceed health-based (or 
health-based surrogate) levels. Id. Consistent with the settlement 
agreement mentioned above, EPA solicits comment as to whether this

[[Page 17473]]

same type of test could be applied to burning of hazardous waste in 
non-Bevill boilers and furnaces. The logic could be that if hazardous 
properties are not contributed by the hazardous waste, the derived from 
rule should not apply.
    EPA's inclination is not to apply any type of significantly 
affected test to residues at this time. The recently-proposed exit 
levels, and methodology, in the Hazardous Waste Identification Rule 
(HWIR) provide a means of automatic exit from the subtitle C system 
when wastes (including derived-from wastes) are no longer hazardous. 
Furthermore, the ``significantly affected'' test is closely linked to 
the Bevill amendment, and in fact defines the scope of that amendment 
in co-processing situations. EPA sees no persuasive reason to apply the 
test to non-Bevill residues, particularly when the Agency has proposed 
a means whereby such residues can automatically exit the system. It 
appears to EPA to be the better approach to make subtitle C exit 
determinations on the basis of hazards actually posed by the waste 
rather than by comparisons with a non-waste baseline. (Indeed, this is 
one component of the significantly affected test already. See 
Sec. 266.112(b)(2).) The Agency solicits comment on this matter, 
however.

E. Applicability of Regulations to Cyanide Wastes

    The Agency has received several inquiries regarding the 
applicability of Sec. 266.100(c)(2)(i) criteria for processing cyanide 
wastes solely for metal recovery. Specifically, cyanide wastes do not 
meet the common dictionary meaning of being an organic, but can be 
destroyed by industrial furnaces. The Agency's intent of this exemption 
was to preclude burning of waste streams that contain greater than 500 
ppm nonmetal compounds listed in Appendix VIII of Part 61, that are 
provided a level of destruction by the furnace. The Agency 
inappropriately chose the word `organic' instead of `nonmetal' in the 
above regulation. An amendment is being proposed to provide the needed 
clarification that wastes containing cyanides are eligible to be 
included in this exemption. We are also proposing similar amendments 
(i.e., revisions to use the term ``nonmetal'' rather than ``organic'') 
to subparagraphs (c)(2)(ii), (c)(3)(i)(B), and (c)(3)(ii).

F. Shakedown Concerns

    There is a concern within the Agency that some new units do not 
effectively use their allotted 720 hour pre-trial burn period (commonly 
referred to as ``shakedown'') or extensions thereof to correct 
operational problems prior to the trial burn period. This ineffective 
use of the pretrial burn period can potentially lead to emission 
exceedances which pose unnecessary risks to human health and the 
environment. In addition, failure(s) during trial burn testing at one 
or more test conditions reduce a facility's flexibility to burn 
hazardous waste in a subsequent permit developed from the trial burn or 
may even lead to a need to perform other trial burns or a termination 
of the permit. A failure to perform adequate shakedown may also lead to 
difficulties in making an interpretation of trial burn data and in 
setting of permit conditions due to excessive variability in trial burn 
operation.
    The Agency believes that an approach using system start-up and 
system problem solving with the use of a non-hazardous waste feed 
followed by a gradual, carefully planned introduction of hazardous 
waste feed is essential to avoid the potential problems which could 
result from the burning of hazardous waste in an undiagnosed system 
which may not yet be operating at steady state conditions. The absence 
of this type of approach has caused many previous trial burns not to be 
carried through to completion or has caused them to occur in a very 
different fashion from that prescribed in the trial burn plan. Other 
efforts during the trial burn have resulted in diminished operating 
allowances or in the need for additional trial burn testing. As a 
result of these occurrences, the Agency is proposing three options 
which center around the pretrial burn period in an attempt to enhance 
regulatory control over trial burn testing. The Agency is also 
requesting comment on the applicability of these options to interim 
status facilities. The shakedown period has, in the past, been applied 
exclusively to new facilities and has not addressed existing facilities 
operating under interim status. The Agency believes that these options 
could apply to interim status facilities if the newly proposed waste to 
be burned represented a very different waste than that which had been 
burned.
    As its primary option, the Agency would require that facilities be 
required to show the Director prior to trial burn dates being scheduled 
that the facility has provided a minimum showing of operational 
readiness. This showing of operational readiness would be one which has 
been established by the Director and would be incorporated as part of 
the permit application process for both interim status and new devices. 
The manner in which this notification of readiness would occur would be 
determined by the Director. A trial burn could not be scheduled until 
this minimum showing to the Director has occurred. Criteria for trial 
burn readiness would include, but would not be limited to the following 
examples: (1) The ability of a facility to show that it has operated 
the device to be permitted under its planned trial burn conditions 
(e.g. temperature, feedrate) for a specified time period set by the 
Director, or (2) the ability of a facility to operate for a designated 
period of time (to be established by the Director) without an Automatic 
Waste Feed Cut-Off (AWFCO) occurring. To show readiness to the 
Director, the composition of the feed stream to the device during this 
showing would need to be nearly identical (if not identical) to the 
waste intended to be burned during the operational lifetime of the 
facility. This similarity should be consistent with respect to the 
physical, thermal, and fluid characteristics of the waste not only 
being burned during the trial burn tests, but also during the lifetime 
of the facility. It is the Agency's belief that facilities which fail 
their trial burn tests often fail because facilities tend to stress 
their devices for the first time only during trial burn testing. The 
system has to that point never undergone ``break point'' testing with 
an increased feedrate or maximum capacity feedrate. A trial burn should 
not be scheduled until a facility has shown the Director that it can 
operate without constant shutdowns at feedrates consistent with that of 
the trial burn.
    A second option which the Agency offers for comment is a more 
restrictive option. This option proposes requirements on both the 
operations prior to and following the shakedown period. It incorporates 
the notification requirements found in the primary option along with an 
additional notification requirement which would occur prior to the 
beginning of shakedown. This option would require a facility to notify 
the Director that it has achieved steady state operation with non-
hazardous waste during this period leading up to shakedown at 
operational levels set by Director (e.g. flowrates) which are 
comparable to that to be tested at trial burn and to certify that the 
device is ready to begin shakedown operations. As before, this option 
would also require a facility to notify the Director following 
shakedown that operational readiness with hazardous waste has been 
achieved and to certify that the device is ready for trial burn tests. 
Although this option would impose two more operational

[[Page 17474]]

requirements for a facility, it would ensure that the facility has 
brought the device up to operational standards whereby the addition of 
hazardous waste would not represent an excessive risk to human health 
or the environment. The Agency believes that this option would also 
provide for a more efficient trial burn since it has required a 
facility to become operational without constant shutdowns prior to the 
trial burn prior to shakedown and after shakedown. Portions of this 
option may not be directly applicable to interim status facilities 
since they have been burning hazardous waste to date and may have most 
of their operational problems worked out.
    A third option upon which the Agency is requesting comment is a 
``guidance only'' option. Although this option would not impose any 
specific regulatory requirements for a showing of operational readiness 
prior to or after a shakedown period, it would provide guidance to 
industry and permit writers on how to effectively achieve preparedness 
prior to a trial burn without the need of formalizing it within the 
constraints of the regulations. Permit writers would have the ability, 
as they do now, to set readiness demonstration requirements if they 
deem it necessary for a specific site.

G. Extensions of Time Under Certification of Compliance

    The Boiler and Industrial Furnace Rule, at 40 CFR 
Sec. 266.103(c)(7), allows a facility to obtain a case-by-case 
extension under certain circumstances when events were outside of the 
control of the facility. There have been questions as to whether this 
provision meant that after August 21, 1992, a facility could no longer 
apply for a case-by-case extension. The Agency wants to clarify that it 
never intended this restrictive interpretation and so is proposing to 
amend this section to provide the clarification. EPA intended the case-
by-case extension to apply at any time during the certification of 
compliance cycle, including during Revised Certification of Compliance 
under Sec. 266.103(c)(8), and during Periodic Recertifications under 
Sec. 266.103(d). See 56 FR at 7182 (February 21, 1991). The basis of 
granting the case-by-case extension is proposed to remain unchanged by 
today's rule. Additionally, EPA is clarifying that the automatic one 
year extension is not valid for facilities which were not in existence 
on August 21, 1991.

H. Technical Amendments to the BIF Rule

1. Facility Requirements at Closure
    EPA is today proposing to amend Sec. 266.103(l) to stipulate that 
at closure, the owner or operator must remove all hazardous waste and 
hazardous waste residues not only from the boiler or industrial 
furnace, but also from its air pollution control system (APCS). 
Although the APCS is an integral part of the facility, this minor 
amendment will make it explicitly clear that no hazardous waste or 
residues can remain in the APCS after closure.
2. Definitions under the BIF Rule
    We are adding several definitions under Sec. 260.10 for frequently 
used terms in combustion regulations like fugitive emissions, automatic 
waste feed cutoff system, run, air pollution control system and 
operating record. The purpose is to clarify these technical terms of 
thermal treatment, expedite permit writing as well as increase the 
enforceability of obvious technical violations. Some of these 
definitions already exist in the air regulations.

I. Clarification of Regulatory Status of Fuel Blenders

    EPA is proposing to revise 40 CFR 266.101 (``Management prior to 
burning'') to clarify that fuel blending activities, including those 
which constitute treatment, are regulated under RCRA. Section 266.101 
(formerly 266.34) was written with the understanding that hazardous 
waste fuel-blending activities were traditionally performed in 
containers or tank systems where the storage standards of Part 264 
could be applied. The Agency believes that protection of human health 
and the environment is accomplished when the permit addresses the 
containment of the waste being treated. Therefore, no direct reference 
to ``treatment'' was included in Section 266.34; treatment was 
understood to be implicit in the regulation, as shown by the reference 
in section 261.6 to the ``* * * applicable provisions of Part 270.'' 
EPA has in fact explicitly interpreted Sec. 266.101 (formerly 
Sec. 266.34) to require tank storage standards to apply to tanks in 
which hazardous waste fuels are blended. See 52 FR 11820 (April 13, 
1987).
    More recently, it has come to the Agency's attention that fuel 
blenders may be using devices such as microwave units and distillation 
columns in their hazardous waste handling operations that differ from 
the traditional fuel-blending practices. These practices are, in fact, 
hazardous waste treatment activities requiring a RCRA permit, without 
which the unit cannot operate. For many such operations, the 
``miscellaneous unit'' requirements of Part 264, Subpart X, would 
apply. Due to various inquiries regarding this issue, EPA has written 
several policy memoranda confirming that treatment, as well as storage, 
conducted by fuel blenders requires a RCRA permit. These memoranda are 
part of the Agency's RCRA Permit Policy Compendium and are available 
from the RCRA Hotline. They are also included in this rulemaking 
docket. EPA is taking this opportunity to clarify this issue in the 
regulations by revising the language in Sec. 266.101.

J. Change in Reporting Requirements for Secondary Lead Smelters Subject 
to MACT

    EPA recently promulgated MACT standards for the secondary lead 
smelter source category. 60 FR 29750 (June 23, 1995). In that rule, the 
Agency found, with unanimous support from commenters, that RCRA 
emission standards were unnecessary at the present time for these 
sources since the MACT standards provide significant health protection, 
area secondary lead sources will be regulated by these MACT standards, 
and the ultimate issue of the protectiveness of the standard will be 
evaluated during the section 112(f) residual risk determination.
    EPA is proposing here to modify existing Sec. 266.100(c), which 
provides an exemption from RCRA air emission standards for (among other 
sources) industrial furnaces burning hazardous waste solely for 
material recovery. Secondary lead smelters complying with conditions 
enumerated in Sec. 266.100(c)(l) and (3) are among this type of 
industrial furnace. The Agency is proposing to amend Sec. 266.100(c)and 
is proposing to add a new Sec. 266.100(g) to state that RCRA provisions 
for air emissions do not apply to secondary lead smelters when the MACT 
rule takes effect (in June, 1997), provided the smelters do not burn 
hazardous wastes containing greater than 500 ppm nonmetal hazardous 
constituents (or burn wastes enumerated in 40 CFR Part 266 Appendix 
XI), submit a one-time notice to EPA or an authorized state, sample and 
analyze as necessary to document the basis for their claim, and keep 
appropriate records. These amendments also could take the form of an 
exemption (subject to the same conditions) for such secondary lead 
smelters from the present proposed rule.
    This proposed amendment is similar to the exemption found in the 
existing

[[Page 17475]]

RCRA BIF rules but does eliminate certain recordkeeping and reporting 
requirements for secondary lead smelters presently required as a 
condition of the RCRA exemption. The Agency tentatively does not 
believe these extra reporting requirements are needed once the MACT 
standards take effect. At the same time, secondary lead smelters 
choosing to burn hazardous wastes different from those evaluated in the 
secondary lead NESHAP (i.e. hazardous wastes with greater than 500 ppm 
toxic nonmetals or those hazardous waste not listed in Appendix XI to 
Part 266) would have to meet applicable standards for hazardous waste 
combustion units (i.e. either the existing BIF standards or revised 
standards based on MACT), as well as those for secondary lead smelters. 
EPA would administer this proposal by not requiring a secondary lead 
smelter that has already submitted a notification to EPA or an 
authorized state under existing 266.100(c)(l) or (3), to renotify under 
proposed 266.100 (g).

PART SEVEN: ANALYTICAL AND REGULATORY REQUIREMENTS

I. Executive Order 12866

    Under Executive Order 12866, (58 FR 51735 (October 4, 1993)) the 
Agency must determine whether this regulatory action is 
``significant.'' A determination of significance will subject this 
action to full OMB review and compliance under Executive Order 12866 
requirements. The order defines ``significant regulatory action'' as 
one that is likely to result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more, 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or state, local, or tribal governments or 
communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlement, grants, 
user fees, or loan programs, or the rights and obligations of 
recipients thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the terms of the Executive Order.
    The Agency believes that today's proposal, represents a significant 
action. If adopted, the proposed rule would most likely result in a 
cost greater than $100 million. As a result, this rulemaking action, 
and supporting analyses, are subject to full OMB review under the 
requirements of the Executive Order. The Agency has prepared 
``Regulatory Impact Assessment for Proposed Hazardous Waste Combustion 
MACT Standards'' and ``Addendum to the Regulatory Impact Assessment for 
Proposed Hazardous Waste Combustion MACT Standards'' in support of 
today's action; this report is available in the public docket for 
today's rule. A summary of this analysis and findings is presented 
below.

II. Regulatory Options

    During the regulatory developmental phases, EPA considered seven 
different regulatory MACT options for existing sources. Refer to the 
RIA for a detailed discussion of the seven options. This preamble 
discusses and assesses the floor option and the Agency preferred 
option. For more detail on the specific methodology used in developing 
floor and ``beyond-the-floor'' control levels, the reader should refer 
to the preamble Options section, Part Four of this preamble. Below is a 
summary of the impact of floor levels and the preferred option 1 on the 
combustion industry.

III. Assessment of Potential Costs and Benefits

A. Introduction

    The Agency has prepared a regulatory impact assessment to accompany 
today's proposed rulemaking. The Agency has evaluated cost, economic 
impacts, and other impacts such as environmental justice, unfunded 
mandates, regulatory takings, and waste minimization incentives. The 
focus of the economic impact assessment was on how the MACT standards 
may affect the hazardous waste-burning industry. The Agency would like 
to note that although the cement kiln industry profits are generated by 
two components: cement production and hazardous waste burning, the RIA 
only estimated the impact the MACT standards will have on hazardous 
waste burning. The Agency is in the process of beginning an analysis 
that will study the impact of today's rule on cement production, cement 
prices, and competition in the cement industry. The Agency would like 
to solicit comments and request information in this area as we begin 
our research.
    To develop cost estimates, EPA categorized the combustion units by 
size, and estimated engineering costs for the air pollution control 
devices (APCDs) needed to achieve the standards in the regulatory 
options. Based on information regarding current emissions and APCD 
trains EPA developed assumptions regarding the type of upgrades that 
units would require. Because EPA's data was limited, this analysis is 
meant to develop estimates of national economic impacts, and not site 
specific impacts.

B. Analysis and Findings

    Total annual compliance costs for the floor option and the Agency's 
proposed standards range in costs from an estimated $93 million to $136 
million.

                                          Total Annual Compliance Costs                                         
                                                   [Millions]                                                   
----------------------------------------------------------------------------------------------------------------
                                                       Cement               Commercial      On-site             
                      Options                          kilns    LWA kilns  incinerators  incinerators    Total  
----------------------------------------------------------------------------------------------------------------
6 percent Floor....................................        $27         $2          $13           $50         $93
6 percent BTF......................................         44          4           20            67         136
----------------------------------------------------------------------------------------------------------------

    This rule will result in a significant impact to the combustion 
industry. The regulatory impact assessment used a number screening 
indicators to assess the impact of this rule. One indicator the 
analysis used was the average total annual compliance cost per unit. 
This indicator assesses the relative impact the rule has on each 
facility type in the combustion universe. According to this indicator, 
cement kilns incur the greatest average incremental cost per unit 
totaling $770,000 annually for the floor and $1.1 million annually for 
the proposed standards, which include beyond the floor standards. The 
cost per unit for LWAKs range from $490,000 to $825,000 and for on-site 
incinerators from $340,000 to $486,000. Commercial incinerators annual 
average cost per unit total $493,000 for the floor and

[[Page 17476]]

$730,000 for the proposed standards. One should note however, that the 
per unit costs are presented assuming no market exit. Once market exit 
occurs, per unit should be significantly lower particularly for on-site 
incinerators.
    Looking at the price per ton, in the baseline, cement kilns have 
the lowest cost ($104 per ton) to burn hazardous waste today with 
commercial incinerators have $800 per ton costs and on-site 
incinerators have $28,460 per ton costs. For compliance costs, cement 
kilns have the smallest impact ($40 to $50 per ton) with on-site 
incinerators experiencing a high compliance cost of $47 to $57 per ton.
    EPA also looked at baseline cost of burning hazardous waste as a 
percentage of compliance cost. This indicator assesses the relative 
impact of facilities within the sector but it also can be a predictor 
for how prices might increase for burning hazardous waste. According to 
the table below, the floor compliance costs are 40 percent of the 
current baseline cost of burning hazardous waste for cement kilns and 
over 20 percent for LWAKs. Many on-site incinerators and commercial 
incinerators have existing APCDs and have larger volumes of waste to 
distribute compliance costs across, thus compliance costs tend to be a 
smaller addition to baseline costs.

                              Average Total Annual Baseline--Incremental Compliance                             
                                                 [Cost per Ton]                                                 
----------------------------------------------------------------------------------------------------------------
                                                                  Cement               Commercial      On-site  
                            Options                               kilns    LWA kilns  incinerators  incinerators
----------------------------------------------------------------------------------------------------------------
Baseline......................................................       $104       $194         $806       $28,500 
6 percent Floor...............................................        $40        $39          $23           $47 
6 percent BTF.................................................         50         56           31            57 
----------------------------------------------------------------------------------------------------------------
Note: Baseline costs were calculated by identifying all costs associated with hazardous waste burning. Thus, for
  commercial incinerators and on-site incinerators, all costs associated with unit construction, operation and  
  maintenance are included. This also includes RCRA permits and existing APCDs. The costs for on-site burners   
  are extremely high because total costs for incineration is distributed across the small amount of hazardous   
  waste burned. For cement kilns and LWAKs, only those incremental costs associated with burning hazardous waste
  are included such as, permits. The cost of the actual units (which have a primary purpose of producing cement 
  or aggregate) are not included in the baseline. Also these costs are after consolidation occurs.              

    Although cement kilns incur a significant impact, they still have 
the lowest average waste burning cost after the regulation. As the 
table above illustrates in the post-regulatory scenario, cement kilns 
cost per ton for burning waste would total $154 compared to a cost per 
ton for commercial incinerators of $837. EPA expects that this 
advantage for cement kilns in the market will allow them to continue to 
set the market price for waste burning.
    Not all facilities however, will be able to absorb the compliance 
cost to this rule and remain competitive. The economic impact 
assessment estimates that of the facilities which are currently burning 
hazardous waste 3 cement kilns, 2 LWAK, 6 commercial incinerators and 
85 on-site incinerators will likely stop burning waste in the long 
term. Most of these units are ones which burn smaller amount of 
hazardous waste.

C. Total Incremental Cost per Incremental Reduction in HAP Emissions

    Cost effectiveness is calculated by first estimating the compliance 
expenditures associated with the specific hazardous air pollutant 
(HAP). The estimation of costs per HAP is often difficult to ascertain 
because the air pollution control devices usually control more than one 
HAP. Therefore, estimation of precise cost per HAP was not feasible. 
Once the compliance expenditures has been estimated, the total mass 
emission reduction achieved when combustion facilities comply with the 
standards for a given option must be estimated. With the total 
compliance costs and the total mass emissions, the total incremental 
cost per incremental reduction in HAP emissions can be estimated. For a 
more detailed discussion of how the cost per HAP was calculated, please 
see chapter 5 of ``Regulatory Impact Assessment for Proposed Hazardous 
Waste Combustion MACT Standards''.
    Results of the cost-effectiveness calculations for each HAP for all 
facilities are found below. For results on a facility-type level, 
please see chapter 5 of the RIA. Considering all facilities as a group, 
the results indicate that dioxin, mercury, and metals cost per unit 
reduction are quite high. This is the case because small amounts of the 
dioxin and metals are released into the environment. For other 
pollutants, expenditures per ton are much lower.

                  Cost Effectiveness for All Facilities                 
------------------------------------------------------------------------
                                                     Baseline  6 percent
                                                       to 6     floor to
              HAP                       Unit         percent   6 percent
                                                      floor       BTF   
------------------------------------------------------------------------
D/F............................  $/g..............    $12,000   $560,000
Mercury........................  $/lb.............      2,600      5,400
LVM............................  $/Mton...........    407,000         NA
SVM............................  $/Mton...........    315,000         NA
Chlorine.......................  $/Mton...........      7,000      2,240
Particulate....................  $/Mton...........      4,400      3,200
CO.............................  $/Mton...........      1,360         NA
THC............................  $/Mton...........      2,800         NA
------------------------------------------------------------------------
Note: NA = Zero incremental reduction in HAP emissions (Dollars divided 
  by zero = NA).                                                        

D. Human Health Benefits

1. Dioxin benefits
    Polychlorinated dibenzo-p-dioxins and polychlorinated 
dibenzofurans, hereafter referred to collectively as dioxins, are 
ubiquitous in the environment. The more highly chlorinated dioxins, 
which are extremely stable under environmental conditions, persist in 
the environment for decades and are found particularly in soils, 
sediments, and foods. It has been hypothesized that the primary 
mechanism by which dioxins enter the terrestrial food chain is through 
atmospheric deposition.210 Dioxins may be emitted directly to the 
atmosphere by a variety of anthropogenic sources or indirectly through 
volatilization or particle resuspension from reservoir

[[Page 17477]]

sources such as soils, sediments, and vegetation.
---------------------------------------------------------------------------

    \210\ USEPA, ``Estimating Exposure to Dioxin-Like Compounds'', 
Volume I, June 1994.
---------------------------------------------------------------------------

    The most well known incident of environmental contamination with 
dioxins occurred in Seveso, Italy in an industrial accident. Symptoms 
of acute exposures such as chloracne occurred immediately following the 
incident. Since then, significant increases in certain types of cancers 
have also been observed.211 After evaluating a variety of 
carcinogenicity studies in human populations and laboratory animals, 
EPA has concluded that 2,3,7,8-tetrachlorodibenzo-p-dioxin and related 
compounds are probable human carcinogens.212 EPA estimates that a 
dose of 0.01 picograms on a toxicity equivalent (TEQ) basis per 
kilogram body weight per day is associated with a plausible upper bound 
lifetime excess cancer risk of one in one million (1 x 10-6).213 
Toxicity equivalence is based on the premise that a series of common 
biological steps are necessary for most if not all of the observed 
effects, including cancer, from exposures to 2,3,7,8 chlorine-
substituted dibenzo-p-dioxin and dibenzofuran compounds in vertebrates, 
including humans. Given the levels of background TEQ exposures 
discussed below, as many as 600 cancer cases may be attributable to 
dioxin exposures each year in the United States.
---------------------------------------------------------------------------

    \211\ USEPA, ``Health Assessment Document for 2,3,7,8-
Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds, Volume II, 
June 1994.
    \212\ USEPA, ``Health Assessment Document for 2,3,7,8-
Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds, Volume 
III,'' August 1994.
    \213\ Ibid.
---------------------------------------------------------------------------

    EPA has also concluded that there is adequate evidence from both 
human populations and laboratory animals, as well as other experimental 
data, to support the inference that humans are likely to respond with a 
broad spectrum of non-cancer effects from exposure to dioxins if 
exposures are high enough. Although it is not possible given existing 
information to state exactly how or at what levels exposed humans will 
respond, the margin of exposure between background TEQ levels and 
levels where effects are detectable in humans is considerably smaller 
than previously thought.214
---------------------------------------------------------------------------

    \214\ Ibid.
---------------------------------------------------------------------------

    Dioxins are commonly found in food produced for human consumption. 
Consumption of dioxin contaminated food is considered the primary route 
of exposure in the general population. EPA evaluated data collected in 
four U.S. studies, three of which included analyses of all 2,3,7,8 
chlorine-substituted congeners of dibenzo-p-dioxin and dibenzofuran. 
EPA's evaluation concluded that ``background'' levels in beef, milk, 
pork, chicken, and eggs are approximately 0.5, 0.07, 0.3, 0.2, and 0.1 
parts per trillion fresh weight, respectively, on a toxicity equivalent 
(TEQ) basis.215 EPA then used these background levels, together 
with information on food consumption, to estimate dietary intake in the 
general population. That estimate is 120 picograms TEQ per day.216
---------------------------------------------------------------------------

    \215\ USEPA, ``Estimating Exposure to Dioxin-Like Compounds,'' 
Volume II, June 1994.
    \216\ Ibid.
---------------------------------------------------------------------------

    EPA has also collected data on dioxins in fish taken from 388 
locations nationwide and found that at 89 percent of the locations, 
fish contained detectable levels of at least two of the dioxin and 
furan compounds for which analyses were conducted.217 (Of the 
2,3,7,8 chlorine-substituted congeners, only octachlorodibenzo-p-dioxin 
and octachlorodibenzofuran were not analyzed.) Seven of the compounds, 
including 2,3,7,8-TCDD, were detected at over half the locations. 
Detection limits were generally at or below 1 part per trillion on a 
toxicity equivalent basis. The median (50th percentile) concentration 
in fish on a toxicity equivalent basis (TEQ) was 3 parts per trillion 
(ppt) while the 90th percentile was approximately 30 ppt TEQ. Five 
percent of the sites exceeded 50 ppt TEQ. At most sites, both a 
composite sample of bottom feeders and a composite sample of game fish 
were collected. At sites considered representative of background 
levels, the median concentration was 0.5 ppt TEQ.
---------------------------------------------------------------------------

    \217\ USEPA, ``National Study of Chemical Residues in Fish,'' 
Office of Science and Technology, September 1992.
---------------------------------------------------------------------------

    EPA has estimated that hazardous waste incinerators and hazardous 
waste-burning cement and lightweight aggregate kilns currently emit 
0.08, 0.86, and less than 0.01 kg TEQ of dioxins per year, 
respectively, or a total of 0.94 kg TEQ per year. Excluding non-
hazardous waste-burning cement kilns, an emission rate of approximately 
9 kg TEQ per year is estimated for all other U.S. sources.218 
Therefore, hazardous waste-burning sources represent about 9 percent of 
total anthropogenic emissions of dioxins in the U.S. The following 
table shows hazardous waste-burning sources relative to other major 
emitters of dioxins:
---------------------------------------------------------------------------

    \218\ USEPA, ``Estimating Exposure to Dioxin-Like Compounds'', 
Volume II, June 1994.

------------------------------------------------------------------------
                                                                 Dioxin 
                                                               emissions
                       Source category                          (kg TEQ/
                                                                 year)  
------------------------------------------------------------------------
Medical Waste Incinerators...................................        5.1
Municipal Waste Incinerators.................................        3.0
Hazardous Waste-burning Incinerators, Cement Kilns, and                 
 Lightweight Aggregate Kilns.................................        0.9
------------------------------------------------------------------------

    There is information to suggest, however, that dioxin emissions 
nationwide from all sources are higher than have been estimated. Public 
comments on EPA's dioxin reassessment have identified a number of 
possible additional sources of dioxins, including decomposition of 
materials containing chlorophenols (i.e. wood treated with PCP), metals 
processing industries, diesel fuel and unleaded gasoline, PCB 
manufacturing, and re-entrainment of reservoir sources. Reservoir 
sources may be a significant source of vapor phase dioxins. On the 
other hand, emissions from at least one of the sources, medical waste 
incinerators, is probably significantly overestimated. Supporting the 
view that dioxin emissions may be higher than previously estimated are 
indications that deposition may be considerably greater than can be 
accounted for by presently identified emissions.
    The impact of emissions on exposure and risk depends on the 
relative geographic locations of the emission sources and receptors 
which contribute to exposure and risk, primarily farm animals. This 
applies to both near field dispersion and long-range transport and it 
affects exposure and risk both in determining whether the trajectory of 
an air parcel impacts receptors of concern and in determining the 
chemical fate of the emissions. The fate of dioxins depends on 
degradation processes that can occur in the atmosphere. These processes 
can increase or decrease the toxicity of the original emissions through 
dechlorination. This process can have different effects on different 
emission sources, depending on the congener distributions, residence 
time in the atmosphere, and climatic conditions.
    Considering all these factors, it is apparent that hazardous waste-
burning sources contribute significantly to the overall loading of 
dioxins to the environment, although the relative magnitude of the 
contribution remains to be determined. While there is not a one-to-one 
relationship between emissions and risk, it may be inferred that 
hazardous waste-burning sources likely do contribute significantly to 
dioxin levels in foods used for human consumption and, to an extent as 
yet unknown, the estimated 600 cancer

[[Page 17478]]

cases attributable to dioxin exposures annually.
    EPA estimates that dioxin emissions from hazardous waste-burning 
sources will be reduced to 0.07 kg TEQ per year at the floor levels and 
to 0.01 kg TEQ per year at the proposed beyond the floor standard. 
These reductions would result in decreases of approximately 8 and 9 
percent, respectively in total estimated anthropogenic U.S. emissions. 
EPA expects that reductions in dioxin emissions from hazardous waste-
burning sources, in conjunction with reductions in emissions from other 
dioxin-emitting sources, will help reduce dioxin levels over time in 
foods used for human consumption and, therefore, reduce the likelihood 
of adverse health effects, including cancer, occurring in the general 
population.
2. Mercury Benefits
    Mercury has long been a concern in both occupational and 
environmental settings. The most bioavailable form of mercury and, 
therefore, the form most likely to have an adverse effect, is methyl 
mercury. Human exposures to methyl mercury occur primarily from 
ingestion of fish. As a result of mercury contamination, there are 
currently fish consumption bans or advisories in effect for at least 
one waterbody in over two thirds of the States.
    Nationally, about 60 percent of all fish consumption bans and 
advisories are due to mercury. In several States the mercury advisories 
are statewide, with the most widespread concerns being in the northern 
Great Lakes states and Florida. The bans and advisories vary from State 
to State with respect to the levels of concern, the recommended limits 
on consumption, and other factors. Therefore, it is difficult to 
develop a national estimate of potential risk based on this 
information. Nevertheless, these bans and advisories provide one 
indication of the extent and severity of mercury contamination.
    Even low levels of mercury in surface waters can lead to high 
levels of mercury in fish. EPA has estimated that bioaccumulation 
factors, which represent the ratio of the total mercury concentration 
in fish tissue to the total concentration in filtered water, range from 
5,000 to 10,000,000 depending on the species of fish, the age of the 
fish, and the waterbody the fish inhabit.
    The most well known example of mercury poisoning from ingestion of 
fish occurred in the vicinity of Minamata Bay, Japan. Severe 
neurological effects resembling cerebral palsy occurred in the 
offspring of exposed pregnant women. EPA has estimated what it 
considers a safe level of exposure to methyl mercury. This level, 
referred to as the reference dose, is 1E-4 mg/kg-day. The reference 
dose is based on an evaluation of 81 maternal-infant pairs exposed to 
methyl mercury in an incident in Iraq in which methyl mercury treated 
seed grain was diverted for use in making bread. Sources of uncertainty 
in the reference dose are the relatively small number of maternal-
infant pairs in the Iraqi study, the short duration of maternal 
exposure (approximately three months), latency in the appearance of 
effects (from as little as a month to as long as a year), possible 
misclassification of maternal exposures, differences in the vehicle of 
exposure (i.e., grain versus fish), and the selection of the neurologic 
and behavioral endpoints used in the analysis. EPA intends to further 
evaluate the reference dose for methyl mercury when the results from 
studies of fish-eating populations become available.
    EPA collected data on chemical residues in fish taken from 388 
locations nationwide and found that at 92 percent of the locations, 
fish contained detectable levels of mercury.219 (Detection limits 
varied between 0.001 and 0.05 parts per million.) The median (50th 
percentile) mercury concentration in fish was 0.2 ppm while the 90th 
percentile was 0.6 ppm. Two percent of the sites exceeded 1 ppm. At 
most sites, both a composite sample of bottom feeders and a composite 
sample of game fish were collected. The highest concentration, 1.8 ppm, 
was measured at a remote site considered to represent background 
conditions.
---------------------------------------------------------------------------

    \219\ USEPA, ``National Study of Chemical Residues in Fish,'' 
Office of Science and Technology, September 1992.
---------------------------------------------------------------------------

    Similar results have been obtained in other studies, strongly 
suggesting that long-range atmospheric transport and deposition of 
anthropogenic emissions is occurring. Air emissions of mercury 
contribute, then, to both regional and global deposition, as well as 
deposition locally. Congress, in fact, explicitly found this to be the 
case and required EPA to prioritize MACT controls for mercury for this 
reason. (See S. Rep. No. 228, 101st Cong. 1st Sess. at 153-54.)
    An indication of the significance of mercury contamination in fish 
is illustrated by combining data on the levels of mercury in fish with 
data on fish consumption and comparing it to the reference dose for 
methyl mercury. For example, a fish consumption rate of 140 g/day (a 
90th percentile rate associated with recreational fishing) in 
conjunction with a mercury concentration of 0.6 g/g (a 90th 
percentile concentration) translates into an average daily dose of 1E-3 
mg/kg-day, or 10 times the reference dose. Using the same fish 
concentration with a mean fish consumption rate for recreational 
anglers of 30 g/day gives a dose that is three times the reference 
dose. At the median fish concentration of 0.2 g/g and a fish 
consumption rate of 30 g/day, the dose is nearly 90 percent of the 
reference dose. These results indicate that for persons who eat 
significant amounts of freshwater fish, exposures to mercury are 
significant when compared with EPA's estimate of the threshold at which 
effects may occur in susceptible individuals. However, it must be 
recognized that EPA's threshold estimate represents a lower bound; the 
true threshold may be higher than EPA's estimate.
    EPA has estimated that hazardous waste incinerators and hazardous 
waste-burning cement and lightweight aggregate kilns currently emit 
4.2, 5.6, and 0.3 Mg of mercury per year, respectively, or a total of 
10.1 Mg per year. In addition, EPA estimates that approximately 230 Mg 
per year are emitted by all other U.S. sources. Based on these 
estimates, hazardous waste-burning sources represent about 4 percent of 
total anthropogenic emissions of mercury in the U.S. Therefore, 
hazardous waste-burning sources do contribute to the overall loading of 
mercury to the environment and, it may be inferred, to mercury levels 
in fish.
    EPA estimates that mercury emissions from hazardous waste-burning 
sources will be reduced to 3.3 Mg per year at the proposed floor levels 
and to 2.0 Mg per year at the proposed beyond the floor standard. These 
reductions would result in reductions of total anthropogenic U.S. 
emissions of approximately 3 percent. EPA expects that reductions in 
mercury emissions from hazardous waste-burning sources, in conjunction 
with reductions in emissions from other mercury-emitting sources, will 
help reduce mercury levels in fish over time and, therefore, reduce the 
likelihood of adverse health effects occurring in fish-consuming 
populations.

E. Other Benefits

    Other benefits that EPA investigated included ecological benefits, 
property value benefits, soiling and material damage, aesthetic damages 
and recreational and commercial fishing impacts. Overall, the analysis 
of the ecological risk suggest that only when assuming very high 
emissions water quality criteria is exceeded in the watersheds small in 
size and located near waste combustion facilities. These watersheds are 
typically located near

[[Page 17479]]

cement kilns appear to exceed the water quality criteria. According to 
the property value analysis, there may be property value benefits 
associated with reduction in emission from combustion facilities. The 
property value work is on-going and is undergoing refinements. In 
addition, EPA investigated other benefits such as benefits received 
from avoided clean-up as result of reduced particulate matter releases. 
For further detail, please see chapter 5 of the RIA.

IV. Other Regulatory Issues

A. Environmental Justice

    The U.S. EPA completed analyses that identified demographic 
characteristics of populations near cement plants and commercial 
hazardous waste incinerators and compared them to the populations of 
county and state. The analysis focuses on the spatial relationship 
between cement plants and incinerators and minority and low income 
populations. The study does not describe the actual health status of 
these populations, and how their health might be affected proximity to 
facilities.
    EPA used a sample of 41 cement plants was analyzed from a universe 
of 113 plants and a sample of 21 commercial incinerators was analyzed 
from a universe of 35. The complete methodology results of the analyses 
are found in two reports filed in the docket titled, ``Race , 
Ethnicity, and Poverty Status of the Populations Living Near Cement 
Plants in the United States and Race,'' ``Ethnicity, and Poverty Status 
of the Populations Living Near Commercial Incinerators.'' Below is a 
summary of the key results found in the studies.
    The Agency looked at whether minority percentages within a one mile 
radius are significantly different than the minority percentages at the 
county for all cement plants and sample of incinerators, the results 
are as follows:
     27 percent of the universe of all cement plants (29 
plants) and 37 percent of sample of incinerators (21 plants) have 
minority percentages within a one mile radius which exceed the 
corresponding county minority percentages by more than five percentage 
points.
     36 percent of the universe of all cement plants (41 
plants) and 44 percent of sample of incinerators have minority 
percentages within a one mile radius which fall below the corresponding 
county minority percentages by more than five percentage points.
     38 percent of the universe of all cement plants (43 
plants) and 20 percent of sample of incinerators minority percentages 
within a one mile radius which fall within five percentage points 
(above or below) of the corresponding county minority percentages.
    With regard to the question of whether poverty percentages within a 
one mile radius significantly different from the poverty percentages 
for the county for all cement plants. The results are as follows:
     18 percent of the universe of all cement plants (20 
plants) and 36 percent of the sample of incinerators (21 plants) have 
poverty percentages at a one mile radius which exceed the corresponding 
county poverty percentages by more than five percentage points.
     22 percent of the universe of all cement plants (25 
plants) and 37 percent of the sample of incinerators (21 plants) have 
poverty percentages at a one mile radius which fall below the 
corresponding county poverty percentages by more than five percentage 
points.
     60 percent of the universe of all cement plants (68 
plants) and 28 percent of sample of incinerators (21 plants) have 
poverty percentages at a one mile radius which fall within five 
percentage points (above or below) of the corresponding county poverty 
percentages.

B. Unfunded Federal Mandates

    The Agency also evaluated the proposed MACT standards for 
compliance with the Unfunded Mandates Reform Act (UMRA) of 1995. 
Today's rule contains no Federal mandates under the regulatory 
provisions of Title II of the UMBRA for State, local or tribal 
governments or the private sector. The Agency concluded that the rule 
implements requirement specifically set forth by Congress, as stated in 
the Clean Air Act and the Resource Conservation Recovery Act. In 
addition, promulgation of these MACT standards is not expected to 
result in mandated costs of $100 million or more to any state, local, 
or tribal governments, in any one year. Finally, the MACT standards 
will not significantly or uniquely affect small governments.

C. Regulatory Takings

    EPA found no indication that the MACT standards would be considered 
a ``taking,'' as defined by legislation currently being considered by 
Congress. Property would not be physically invaded or taken for public 
use without the consent of the owner. Also, the MACT standards will not 
deprive property owners of economically beneficial or productive use of 
their property, or reduce the property's value.

D. Incentives for Waste Minimization and Pollution Prevention

    The RIA results do not incorporate waste minimization at this time. 
However, the Agency did analyze the potential for waste minimization 
and the preliminary results suggest that generators have a number of 
options for reducing or eliminating waste at a much lower cost. To 
evaluate whether facilities would adopt applicable waste minimization 
measures, a simplified pay back analysis was used. Using information on 
per-facility capital costs for each technology, EPA estimated the 
period of time required for the cost of the waste minimization measure 
to be returned in reduced combustion expenditures. The assessment of 
waste minimization yields estimates of the tonnage of combusted waste 
that might be eliminated. Comprehensive data to evaluate waste 
minimization were not available. Improved information on the capital 
investment and operating costs associated with waste minimization are 
needed.
    Overall, EPA was able to estimate that 630,000 tons of waste, a 
significant portion of all combusted waste, may be amenable to waste 
minimization. Three waste generating processes account for the 
reduction. These processes include solvent and product recovery, 
product processing waste, and process waste removal and cleaning. EPA 
is continuing analysis of waste minimization options and requests 
comments and information in this area. For a complete description of 
the analysis, see the regulatory impact assessment.

E. Evaluation of Impacts on Certain Generators

    EPA is aware of the potential impact today's proposal may have on 
small business hazardous waste generators. The emission standards 
proposed today will require many combustion facilities to install new 
emission control equipment, undertake expanded monitoring, and comply 
with additional recordkeeping and reporting requirements. Combustion 
facilities will incur higher capital and operating costs as a result of 
today's rule. Some facilities are predicted to leave the waste 
management business altogether. As capacity decreases and costs 
increase, facilities are likely to increase the waste management prices 
they charge generators.
    EPA believes many larger generators will respond to waste 
management cost increases by accelerating their waste

[[Page 17480]]

minimization efforts. By undertaking cost-effective waste minimization 
initiatives, companies can reduce the amount of waste requiring 
combustion, thereby deflecting some of the impacts of increases in 
waste management costs. The same waste minimization options may not be 
so readily available to smaller businesses. Small businesses often do 
not have the financial resources to make the capital or process 
improvements necessary to minimize hazardous waste generation, even if 
such improvements will have a net cost benefit in the long run. In 
addition, small businesses often lack the technical expertise necessary 
for effective waste minimization.
    Those small businesses that are unable to minimize waste generation 
will either incur higher costs to operate their businesses or, if 
allowed under federal and state regulations, manage their hazardous 
wastes using unregulated disposal options. Many small businesses, 
because they generate less than 100 kg per month or less than 10 kg of 
acutely hazardous waste per month, are classified as conditionally 
exempt small quantity generators (CESQGs). CESQGs are exempt from many 
of the generator requirements under 40 CFR 262 and are not required 
under the federal RCRA regulations to manage their wastes in TSDFs. 
Many CESQGs, however, send their wastes to third-party collection 
companies who mix CESQG waste with waste from larger generators and 
manage it as a fully regulated hazardous waste. Increases in waste 
management costs due to today's proposal could encourage some number of 
third-party collection companies to segregate CESQG wastes and manage 
them using less expensive, yet legal, alternatives, such as unpermitted 
boilers, space heaters, and non-TSDF cement kilns.
    EPA plans to revise the Regulatory Impact Assessment (RIA) issued 
with today's rule to include additional analysis, as appropriate and 
feasible, focusing on these issues. EPA is seeking comments on any of 
the issues raised here.

V. Regulatory Flexibility Analysis

    The Regulatory Flexibility Act (RFA) of 1980 requires Federal 
agencies to consider impact on ``small entities'' throughout the 
regulatory process. Section 603 of the RFA calls for an initial 
screening analysis to be preformed to determine whether small entities 
will be adversely affected by the regulation. If affected small 
entities are identified, regulatory alternatives must be considered to 
mitigate the potential impacts. Small entities as described in the Act 
are only those ``businesses, organizations and governmental 
jurisdictions subject to regulation.''
    EPA used information from Dunn & Bradstreet, the American Business 
Directory and other sources to identify small businesses. Based on the 
number of employees and annual sales information, EPA identified 11 
firms which may be small entities. The proposed rule is unlikely to 
adversely affect many small businesses for two important reasons. 
First, few combustion units are owned by businesses that meet the SBA 
definition as a small business. Furthermore, over one-third of those 
that are considered small have a relatively small number of employees, 
but have an annual sales in excess of $50 million per year.
    Second, small entities most impacted by the rule are those that 
burn very little waste and hence face very high cost per ton burned. 
Those that burn very little waste in their existing units will 
discontinue burning hazardous waste rather than comply with the 
proposed rule and dispose of waste off-site. EPA looked at the costs of 
alternative disposal and concludes the costs of discontinuing burning 
wastes will not be so high as to result in a significant impact. 
Therefore, EPA believes that today's proposed rule will have a minor 
impact on small businesses.

VI. Paperwork Reduction Act

    The information collection requirements in this proposed rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. Two 
Information Collection Request (ICR) documents have been prepared by 
EPA. One ICR document covers the reporting and recordkeeping 
requirements for NESHAPs from hazardous waste combustors and the other 
ICR document covers the new and amended reporting and recordkeeping 
requirements for boilers and industrial furnaces burning hazardous 
waste. Copies may be obtained from Sandy Farmer, OPPE Regulatory 
Information Division; U.S. Environmental Protection Agency (2136); 401 
M St., SW; Washington, DC 20460 or by calling (202) 260-2740.
    The annual public reporting and recordkeeping burden for the NESHAP 
collection of information is estimated to average 36 hours per 
response. The annual public reporting and recordkeeping burden for the 
BIF collection of information is estimated to average 2 hours per 
response. These estimates include the time needed to review 
instructions; develop, acquire, install, and utilize technology and 
systems for the purposes of collecting, validating, and verifying 
information, processing and maintaining information, and disclosing and 
providing information; adjust the existing ways to comply with any 
previously applicable instructions and requirements; train personnel to 
respond to a collection of information; search existing data sources; 
complete and review the collection of information; and transmit or 
otherwise disclose the information.
    An Agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations are displayed in 40 CFR Part 9.
    Send comments regarding the burden estimate or any other aspect of 
this collection of information, including suggestions for reducing this 
burden to Chief, OPPE Regulatory Information Division; U.S. 
Environmental Protection Agency (2136); 401 M St., SW; Washington, DC 
20460; and to the Office of Information and Regulatory Affairs, Office 
of Management and Budget, Washington, DC 20503, marked ``Attention: 
Desk Officer for EPA.'' Include the ICR number in any correspondence. 
The final rule will respond to any OMB or public comments on the 
information collection requirements contained in this proposal.

VII. Request for Data

    EPA requests the following data to help refine the RIA:
    (1) Waste Quantity Burned: data on hazardous and non-hazardous 
waste burned at on-site facilities (by combustion unit) broken down by 
quantity of liquids, sludges, and solids.
    (2) Price Data: Aggregate prices by waste type and how they vary by 
geographic region and waste contamination level.
    (3) Combustion Alternatives:

--Information on likelihood of on-site incinerators shipping waste to 
on-site boilers as an alternative.
--Realistic waste minimization practices. Information on how combustion 
and waste minimization prices become attractive.
--Information on the type of commercial incinerator most likely to 
receive waste from on-site facilities to ship waste off-site.

    (4) Capacity: practical capacity levels for each combustion unit.

[[Page 17481]]

Appendix--Comparable Fuel Constituent and Physical Specifications

    Note: All numbers in the tables of this appendix are expressed 
to two significant figures.

              Table 1.--Detection and Detection Limit Values for a Possible Gasoline Specification              
----------------------------------------------------------------------------------------------------------------
                                                                                Concentration        Maximum    
                                Chemical name                                  limit (mg/kg at   detection limit
                                                                               10,000 BTU/lb)        (mg/kg)    
----------------------------------------------------------------------------------------------------------------
Total Nitrogen as N.........................................................               9.2  ................
Total Halogens as Cl........................................................              25    ................
Antimony....................................................................           (\1\)                7.0 
Arsenic.....................................................................           (\1\)                0.14
Barium......................................................................           (\1\)               14   
Beryllium...................................................................           (\1\)                0.70
Cadmium.....................................................................           (\1\)                0.70
Chromium....................................................................           (\1\)                1.4 
Cobalt......................................................................           (\1\)                2.8 
Lead........................................................................           (\1\)                7.0 
Manganese...................................................................           (\1\)                0.70
Mercury.....................................................................           (\1\)                0.10
Nickel......................................................................           (\1\)                2.8 
Selenium....................................................................           (\1\)                0.14
Silver......................................................................           (\1\)                1.4 
Thallium....................................................................           (\1\)               14   
-Naphthylamine.....................................................           (\1\)              670   
,-Dimethylphenethylamine..................................           (\1\)              670   
-Naphthylamine.....................................................           (\1\)              670   
1,1-Dichloroethylene........................................................           (\1\)               34   
1,1,2-Trichloroethane.......................................................           (\1\)               34   
1,1,2,2-Tetrachloroethane...................................................           (\1\)               34   
1,2-Dibromo-3-chloropropane.................................................           (\1\)               34   
1,2-Dichloroethylene (cis- or trans-).......................................           (\1\)               34   
1,2,3-Trichloropropane......................................................           (\1\)               34   
1,2,4-Trichlorobenzene......................................................           (\1\)              670   
1,2,4,5-Tetrachlorobenzene..................................................           (\1\)              670   
1,3,5-Trinitrobenzene.......................................................           (\1\)              670   
1,4-Dichloro-2-butene (cis- or trans-)......................................           (\1\)               34   
1,4-Naphthoquinone..........................................................           (\1\)              670   
2-Acetylaminofluorene.......................................................           (\1\)              670   
2-Chloroethyl vinyl ether...................................................           (\1\)               34   
2-Chloronaphthalene.........................................................           (\1\)              670   
2-Chlorophenol..............................................................           (\1\)              670   
2-Piccoline.................................................................           (\1\)              670   
2,3,4,6-Tetrachlorophenol...................................................           (\1\)              670   
2,4-Dichlorophenol..........................................................           (\1\)              670   
2,4-Dimethylphenol..........................................................           (\1\)              670   
2,4-Dinitrophenol...........................................................           (\1\)              670   
2,4-Dinitrotoluene..........................................................           (\1\)              670   
2,4,5-Trichlorophenol.......................................................           (\1\)              670   
2,4,6-Trichlorophenol.......................................................           (\1\)              670   
2,6-Dichlorophenol..........................................................           (\1\)              670   
2,6-Dinitrotoluene..........................................................           (\1\)              670   
3-3-Dimethylbenzidine.......................................................           (\1\)              670   
3-Methylcholanthrene........................................................           (\1\)              670   
3,3-Dichlorobenzidine.......................................................           (\1\)              670   
4-Aminobiphenyl.............................................................           (\1\)              670   
4-Bromophenyl phenyl ether..................................................           (\1\)              670   
4,6-Dinitro-o-cresol........................................................           (\1\)              670   
5-Nitro-o-toluidine.........................................................           (\1\)              670   
7,12-Dimethylbenz[a]anthracene..............................................           (\1\)              670   
Acetonitrile................................................................           (\1\)               34   
Acetophenone................................................................           (\1\)              670   
Acrolein....................................................................           (\1\)               34   
Acrylonitrile...............................................................           (\1\)               34   
Allyl chloride..............................................................           (\1\)               34   
Aniline.....................................................................           (\1\)              670   
Aramite.....................................................................           (\1\)              670   
Benzene.....................................................................            3500    ................
Benzidine...................................................................           (\1\)              670   
Benzo [a] anthracene........................................................             340                    
Benzo [a] pyrene............................................................             340                    
Benzo [b] fluoranthene......................................................           (\1\)              670   
Benzo [k] fluoranthene......................................................           (\1\)              670   
Bromoform...................................................................           (\1\)               34   
Butyl benzyl phthalate......................................................           (\1\)              670   
                                                                                                                

[[Page 17482]]

                                                                                                                
Carbon disulfide............................................................           (\1\)               34   
Carbon tetrachloride........................................................           (\1\)               34   
Chlorobenzene...............................................................           (\1\)               34   
Chlorobenzilate.............................................................           (\1\)              670   
Chloroform..................................................................           (\1\)               34   
Chloroprene.................................................................           (\1\)               34   
Chrysene....................................................................             340    ................
cis-1,3-Dichloropropene.....................................................           (\1\)               34   
Cresol (o-, m-, or p-)......................................................           (\1\)              670   
Di-n-butyl phthalate........................................................           (\1\)              670   
Di-n-octyl phthalate........................................................             340    ................
Diallate....................................................................           (\1\)              670   
Dibenzo [a,h] anthracene....................................................             340                    
Dibenz [a,j] acridine.......................................................           (\1\)              670   
Dichlorodifluoromethane.....................................................           (\1\)               34   
Diethyl phthalate...........................................................           (\1\)              670   
Dimethoate..................................................................           (\1\)              670   
Dimethyl phthalate..........................................................           (\1\)              670   
Dinoseb.....................................................................           (\1\)              670   
Diphenylamine...............................................................           (\1\)              670   
Disulfoton..................................................................           (\1\)              670   
Ethyl methacrylate..........................................................           (\1\)               34   
Ethyl methanesulfonate......................................................           (\1\)              670   
Famphur.....................................................................           (\1\)              670   
Fluoranthene................................................................           (\1\)              670   
Fluorene....................................................................           (\1\)              670   
Hexachlorobenzene...........................................................           (\1\)              670   
Hexachlorobutadiene.........................................................           (\1\)              670   
Hexachlorocyclopentadiene...................................................           (\1\)              670   
Hexachloroethane............................................................           (\1\)              670   
Hexachlorophene.............................................................           (\1\)            17000   
Hexachloropropene...........................................................           (\1\)              670   
Indeno(1,2,3-cd) pyrene.....................................................           (\1\)              670   
Isobutyl alcohol............................................................           (\1\)               34   
Isodrin.....................................................................           (\1\)              670   
Isosafrole..................................................................           (\1\)              670   
Kepone......................................................................           (\1\)             1300   
m-Dichlorobenzene...........................................................           (\1\)              670   
Methacrylonitrile...........................................................           (\1\)               34   
Methapyrilene...............................................................           (\1\)              670   
Methyl bromide..............................................................           (\1\)               34   
Methyl chloride.............................................................           (\1\)               34   
Methyl ethyl ketone.........................................................           (\1\)               34   
Methyl iodide...............................................................           (\1\)               34   
Methyl methacrylate.........................................................           (\1\)               34   
Methyl methanesulfonate.....................................................           (\1\)              670   
Methyl parathion............................................................           (\1\)              670   
Methylene chloride..........................................................           (\1\)               34   
N-Nitrosodi-n-butylamine....................................................           (\1\)              670   
N-Nitrosodiethylamine.......................................................           (\1\)              670   
N-Nitrosomethylethylamine...................................................           (\1\)              670   
N-Nitrosomorpholine.........................................................           (\1\)              670   
N-Nitrosopiperidine.........................................................           (\1\)              670   
N-Nitrosopyrrolidine........................................................           (\1\)              670   
Naphthalene.................................................................            2800    ................
Nitrobenzene................................................................           (\1\)              670   
o-Dichlorobenzene...........................................................           (\1\)              670   
o-Toluidine.................................................................           (\1\)              670   
O,O-Diethyl O-pyrazinyl phospho- thioate....................................           (\1\)              670   
O,O,O-Triethyl phosphorothionate............................................           (\1\)              670   
p-(Dimethylamino) azobenzene................................................           (\1\)              670   
p-Chloro-m-cresol...........................................................           (\1\)              670   
p-Chloroaniline.............................................................           (\1\)              670   
p-Dichlorobenzene...........................................................           (\1\)              670   
p-Nitroaniline..............................................................           (\1\)              670   
p-Nitrophenol...............................................................           (\1\)              670   
p-Phenylenediamine..........................................................           (\1\)              670   
Parathion...................................................................           (\1\)              670   
Pentachlorobenzene..........................................................           (\1\)              670   
Pentachloroethane...........................................................           (\1\)               34   

[[Page 17483]]

                                                                                                                
Pentachloronitrobenzene.....................................................           (\1\)              670   
Pentachlorophenol...........................................................           (\1\)              670   
Phenacetin..................................................................           (\1\)              670   
Phenol......................................................................           (\1\)              670   
Phorate.....................................................................           (\1\)              670   
Pronamide...................................................................           (\1\)              670   
Pyridine....................................................................           (\1\)              670   
Safrole.....................................................................           (\1\)              670   
Tetrachloroethylene.........................................................           (\1\)               34   
Tetraethyldithiopyrophosphate...............................................           (\1\)              670   
Toluene.....................................................................           35000    ................
Trichloroethylene...........................................................           (\1\)               34   
Trichlorofluoromethane......................................................           (\1\)               34   
Vinyl Chloride..............................................................           (\1\)               34   
----------------------------------------------------------------------------------------------------------------
\1\ Non-detect.                                                                                                 



          Table 2.--Detection and Detection Limit Values for a Possible Number 2 Fuel Oil Specification         
----------------------------------------------------------------------------------------------------------------
                                                                                Concentration        Maximum    
                                Chemical name                                  limit (mg/kg at  detection limits
                                                                                10,000 BTU/lb)       (mg/kg)    
----------------------------------------------------------------------------------------------------------------
Total Nitrogen as N..........................................................          110      ................
Total Halogens as Cl.........................................................           25      ................
Antimony.....................................................................        (\1\)                  6.0 
Arsenic......................................................................        (\1\)                  0.12
Barium.......................................................................        (\1\)                 12   
Beryllium....................................................................        (\1\)                  0.60
Cadmium......................................................................        (\1\)                  0.60
Chromium.....................................................................        (\1\)                  1.2 
Cobalt.......................................................................        (\1\)                  2.4 
Lead.........................................................................            6.6    ................
Manganese....................................................................        (\1\)                  0.60
Mercury......................................................................        (\1\)                  0.11
Nickel.......................................................................        (\1\)                  2.4 
Selenium.....................................................................            0.070  ................
Silver.......................................................................        (\1\)                  1.2 
Thallium.....................................................................        (\1\)                 12   
-Naphthylamine......................................................        (\1\)               1200   
,-Dimethylphenethylamine...................................        (\1\)               1200   
-Naphthylamine......................................................        (\1\)               1200   
1,1-Dichloroethylene.........................................................        (\1\)                 34   
1,1,2-Trichloroethane........................................................        (\1\)                 34   
1,1,2,2-Tetrachloroethane....................................................        (\1\)                 34   
1,2-Dibromo-3-chloropropane..................................................        (\1\)                 34   
1,2-Dichloroethylene (cis- or trans-)........................................        (\1\)                 34   
1,2,3-Trichloropropane.......................................................        (\1\)                 34   
1,2,4-Trichlorobenzene.......................................................        (\1\)               1200   
1,2,4,5-Tetrachlorobenzene...................................................        (\1\)               1200   
1,3,5-Trinitrobenzene........................................................        (\1\)               1200   
1,4-Dichloro-2-butene (cis- or trans-).......................................        (\1\)                 34   
1,4-Naphthoquinone...........................................................        (\1\)               1200   
2-Acetylaminofluorene........................................................        (\1\)               1200   
2-Chloroethyl vinyl ether....................................................        (\1\)                 34   
2-Chloronaphthalene..........................................................        (\1\)               1200   
2-Chlorophenol...............................................................        (\1\)               1200   
2-Piccoline..................................................................        (\1\)               1200   
2,3,4,6-Tetrachlorophenol....................................................        (\1\)               1200   
2,4-Dichlorophenol...........................................................        (\1\)               1200   
2,4-Dimethylphenol...........................................................        (\1\)               1200   
2,4-Dinitrophenol............................................................        (\1\)               1200   
2,4-Dinitrotoluene...........................................................        (\1\)               1200   
2,4,5-Trichlorophenol........................................................        (\1\)               1200   
2,4,6-Trichlorophenol........................................................        (\1\)               1200   
2,6-Dichlorophenol...........................................................        (\1\)               1200   
2,6-Dinitrotoluene...........................................................        (\1\)               1200   
3-3-Dimethylbenzidine........................................................        (\1\)               1200   
3-Methylcholanthrene.........................................................        (\1\)               1200   
3,3-Dichlorobenzidine........................................................        (\1\)               1200   

[[Page 17484]]

                                                                                                                
4-Aminobiphenyl..............................................................        (\1\)               1200   
4-Bromophenyl phenyl ether...................................................        (\1\)               1200   
4,6-Dinitro-o-cresol.........................................................        (\1\)               1200   
5-Nitro-o-toluidine..........................................................        (\1\)               1200   
7,12-Dimethylbenz[a]anthracene...............................................        (\1\)               1200   
Acetonitrile.................................................................        (\1\)                 34   
Acetophenone.................................................................        (\1\)               1200   
Acrolein.....................................................................        (\1\)                 34   
Acrylonitrile................................................................        (\1\)                 34   
Allyl chloride...............................................................        (\1\)                 34   
Aniline......................................................................        (\1\)               1200   
Aramite......................................................................        (\1\)               1200   
Benzene......................................................................           21      ................
Benzidine....................................................................        (\1\)               1200   
Benzo[a]anthracene...........................................................          610      ................
Benzo[a]pyrene...............................................................          610      ................
Benzo[b]fluoranthene.........................................................        (\1\)               1200   
Benzo[k]fluoranthene.........................................................        (\1\)               1200   
Bromoform....................................................................        (\1\)                 34   
Butyl benzyl phthalate.......................................................        (\1\)               1200   
Carbon disulfide.............................................................        (\1\)                 34   
Carbon tetrachloride.........................................................        (\1\)                 34   
Chlorobenzene................................................................        (\1\)                 34   
Chlorobenzilate..............................................................        (\1\)               1200   
Chloroform...................................................................        (\1\)                 34   
Chloroprene..................................................................        (\1\)                 34   
Chrysene.....................................................................          610      ................
cis-1,3-Dichloropropene......................................................        (\1\)                 34   
Cresol (o-, n-, or p-).......................................................        (\1\)               1200   
Di-n-butyl phthalate.........................................................        (\1\)               1200   
Di-n-octyl phthalate.........................................................          610      ................
Diallate.....................................................................        (\1\)               1200   
Dibenzo[a,h]anthracene.......................................................          610      ................
Dibenz[a,j]acridine..........................................................        (\1\)               1200   
Dichlorodifluoromethane......................................................        (\1\)                 34   
Diethyl phthalate............................................................        (\1\)               1200   
Dimethoate...................................................................        (\1\)               1200   
Dimethyl phthalate...........................................................        (\1\)               1200   
Dinoseb......................................................................        (\1\)               1200   
Diphenylamine................................................................        (\1\)               1200   
Disulfoton...................................................................        (\1\)               1200   
Ethyl methacrylate...........................................................        (\1\)                 34   
Ethyl methanesulfonate.......................................................        (\1\)               1200   
Famphur......................................................................        (\1\)               1200   
Fluoranthene.................................................................        (\1\)               1200   
Fluorene.....................................................................        (\1\)               1200   
Hexachlorobenzene............................................................        (\1\)               1200   
Hexachlorobutadiene..........................................................        (\1\)               1200   
Hexachlorocyclopentadiene....................................................        (\1\)               1200   
Hexachloroethane.............................................................        (\1\)               1200   
Hexachlorophene..............................................................        (\1\)              29000   
Hexachloropropene............................................................        (\1\)               1200   
Indeno(1,2,3-cd)pyrene.......................................................        (\1\)               1200   
Isobutyl alcohol.............................................................        (\1\)                 34   
Isodrin......................................................................        (\1\)               1200   
Isosafrole...................................................................        (\1\)               1200   
Kepone.......................................................................        (\1\)               2300   
m-Dichlorobenzene............................................................        (\1\)               1200   
Methacrylonitrile............................................................        (\1\)                 34   
Methapyrilene................................................................        (\1\)               1200   
Methyl bromide...............................................................        (\1\)                 34   
Methyl chloride..............................................................        (\1\)                 34   
Methyl ethyl ketone..........................................................        (\1\)                 34   
Methyl iodide................................................................        (\1\)                 34   
Methyl methacrylate..........................................................        (\1\)                 34   
Methyl methanesulfonate......................................................        (\1\)               1200   
Methyl parathion.............................................................        (\1\)               1200   
Methylene chloride...........................................................        (\1\)                 34   
N-Nitrosodi-n-butylamine.....................................................        (\1\)               1200   
N-Nitrosomorpholine..........................................................        (\1\)               1200   

[[Page 17485]]

                                                                                                                
N-Nitrosopiperidine..........................................................        (\1\)               1200   
N-Nitrosopyrrolidine.........................................................        (\1\)               1200   
N-Nitrosodiethylamine........................................................        (\1\)               1200   
N-Nitrosomethylethylamine....................................................        (\1\)               1200   
Naphthalene..................................................................         1200      ................
Nitrobenzene.................................................................        (\1\)               1200   
o-Dichlorobenzene............................................................        (\1\)               1200   
o-Toluidine..................................................................        (\1\)               1200   
O,O Diethyl O-pyrazinyl phospho-thioate......................................        (\1\)               1200   
O,O,O-Triethyl phosphorothionate.............................................        (\1\)               1200   
p-(Dimethylamino) azobenzene.................................................        (\1\)               1200   
p-Chloro-m-cresol............................................................        (\1\)               1200   
p-Chloroaniline..............................................................        (\1\)               1200   
p-Dichlorobenzene............................................................        (\1\)               1200   
p-Nitroaniline...............................................................        (\1\)               1200   
p-Nitrophenol................................................................        (\1\)               1200   
p-Phenylenediamine...........................................................        (\1\)               1200   
Parathion....................................................................        (\1\)               1200   
Pentachlorobenzene...........................................................        (\1\)               1200   
Pentachloroethane............................................................        (\1\)                 34   
Pentachloronitrobenzene......................................................        (\1\)               1200   
Pentachlorophenol............................................................        (\1\)               1200   
Phenacetin...................................................................        (\1\)               1200   
Phenol.......................................................................        (\1\)               1200   
Phorate......................................................................        (\1\)               1200   
Pronamide....................................................................        (\1\)               1200   
Pyridine.....................................................................        (\1\)               1200   
Safrole......................................................................        (\1\)               1200   
Tetrachloroethylene..........................................................        (\1\)                 34   
Tetraethyldithiopyrophosphate................................................        (\1\)               1200   
Toluene......................................................................          150      ................
Trichloroethylene............................................................        (\1\)                 34   
Trichlorofluoromethane.......................................................        (\1\)                 34   
Vinyl Chloride...............................................................        (\1\)                34    
----------------------------------------------------------------------------------------------------------------
\1\ Non-detect.                                                                                                 



          Table 3.--Detection and Detection Limit Values for a Possible Number 4 Fuel Oil Specification         
----------------------------------------------------------------------------------------------------------------
                                                                                Concentration        Maximum    
                                Chemical name                                  limit (mg/kg at  detection limits
                                                                               10,000 BTU/lb)        (mg/kg)    
----------------------------------------------------------------------------------------------------------------
Total Nitrogen as N.........................................................           1500     ................
Total Halogens as Cl........................................................             10     ................
Antimony....................................................................          (\1\)                11   
Arsenic.....................................................................          (\1\)                 0.23
Barium......................................................................          (\1\)                23   
Beryllium...................................................................          (\1\)                 1.1 
Cadmium.....................................................................          (\1\)                 1.1 
Chromium....................................................................          (\1\)                 2.3 
Cobalt......................................................................          (\1\)                 4.6 
Lead........................................................................              9.9   ................
Manganese...................................................................          (\1\)                 1.1 
Mercury.....................................................................          (\1\)                 0.18
Nickel......................................................................             16     ................
Selenium....................................................................              0.13  ................
Silver......................................................................          (\1\)                 2.3 
Thallium....................................................................          (\1\)                23   
-Naphthylamine.....................................................          (\1\)               200   
,-Dimethylphenethylamine..................................          (\1\)               200   
-Naphthylamine.....................................................          (\1\)               200   
1,1-Dichloroethylene........................................................          (\1\)                17   
1,1,2-Trichloroethane.......................................................          (\1\)                17   
1,1,2,2-Tetrachloroethane...................................................          (\1\)                17   
1,2-Dibromo-3-chloropropane.................................................          (\1\)                17   
1,2-Dichloroethylene (cis- or trans-).......................................          (\1\)                17   
1,2,3-Trichloropropane......................................................          (\1\)                17   
1,2,4-Trichlorobenzene......................................................          (\1\)               200   
1,2,4,5-Tetrachlorobenzene..................................................          (\1\)               200   

[[Page 17486]]

                                                                                                                
1,3,5-Trinitrobenzene.......................................................          (\1\)               200   
1,4-Dichloro-2-butene (cis- or trans-)......................................          (\1\)                17   
1,4-Naphthoquinone..........................................................          (\1\)               200   
2-Acetylaminofluorene.......................................................          (\1\)               200   
2-Chloroethyl vinyl ether...................................................          (\1\)                17   
2-Chloronaphthalene.........................................................          (\1\)               200   
2-Chlorophenol..............................................................          (\1\)               200   
2-Piccoline.................................................................          (\1\)               200   
2,3,4,6-Tetrachlorophenol...................................................          (\1\)               200   
2,4-Dichlorophenol..........................................................          (\1\)               200   
2,4-Dimethylphenol..........................................................          (\1\)               200   
2,4-Dinitrophenol...........................................................          (\1\)               200   
2,4-Dinitrotoluene..........................................................          (\1\)               200   
2,4,5-Trichlorophenol.......................................................          (\1\)               200   
2,4,6-Trichlorophenol.......................................................          (\1\)               200   
2,6-Dichlorophenol..........................................................          (\1\)               200   
2,6-Dinitrotoluene..........................................................          (\1\)               200   
3-3-Dimethylbenzidine.......................................................          (\1\)               200   
3-Methylcholanthrene........................................................          (\1\)               200   
3,3-Dichlorobenzidine.......................................................          (\1\)               200   
4-Aminobiphenyl.............................................................          (\1\)               200   
4-Bromophenyl phenyl ether..................................................          (\1\)               200   
4,6-Dinitro-o-cresol........................................................          (\1\)               200   
5-Nitro-o-toluidine.........................................................          (\1\)               200   
7,12-Dimethylbenz[a]anthracene..............................................          (\1\)               200   
Acetonitrile................................................................          (\1\)                17   
Acetophenone................................................................          (\1\)               200   
Acrolein....................................................................          (\1\)                17   
Acrylonitrile...............................................................          (\1\)                17   
Allyl chloride..............................................................          (\1\)                17   
Aniline.....................................................................          (\1\)               200   
Aramite.....................................................................          (\1\)               200   
Benzene.....................................................................             22                     
Benzidine...................................................................          (\1\)               200   
Benzo[a]anthracene..........................................................            100                     
Benzo[a]pyrene..............................................................            100                     
Benzo[b]fluoranthene........................................................          (\1\)               200   
Benzo[k]fluoranthene........................................................          (\1\)               200   
Bromoform...................................................................          (\1\)                17   
Butyl benzyl phthalate......................................................          (\1\)               200   
Carbon disulfide............................................................          (\1\)                17   
Carbon tetrachloride........................................................          (\1\)                17   
Chlorobenzene...............................................................          (\1\)                17   
Chlorobenzilate.............................................................          (\1\)               200   
Chloroform..................................................................          (\1\)                17   
Chloroprene.................................................................          (\1\)                17   
Chrysene....................................................................            100                     
cis-1,3-Dichloropropene.....................................................          (\1\)                17   
Cresol (o-, m-, or p-)......................................................          (\1\)               200   
Di-n-butyl phthalate........................................................          (\1\)               200   
Di-n-octyl phthalate........................................................            100                     
Diallate....................................................................          (\1\)               200   
Dibenzo[a,h]anthracene......................................................            100                     
Dibenz[a,j]acridine.........................................................          (\1\)               200   
Dichlorodifluoromethane.....................................................          (\1\)                17   
Diethyl phthalate...........................................................          (\1\)               200   
Dimethoate..................................................................          (\1\)               200   
Dimethyl phthalate..........................................................          (\1\)               200   
Dinoseb.....................................................................          (\1\)               200   
Diphenylamine...............................................................          (\1\)               200   
Disulfoton..................................................................          (\1\)               200   
Ethyl methacrylate..........................................................          (\1\)                17   
Ethyl methanesulfonate......................................................          (\1\)               200   
Famphur.....................................................................          (\1\)               200   
Fluoranthene................................................................          (\1\)               200   
Fluorene....................................................................            110                     
Hexachlorobenzene...........................................................          (\1\)               200   
Hexachlorobutadiene.........................................................          (\1\)               200   
Hexachlorocyclopentadiene...................................................          (\1\)               200   
Hexachloroethane............................................................          (\1\)               200   

[[Page 17487]]

                                                                                                                
Hexachlorophene.............................................................          (\1\)              5000   
Hexachloropropene...........................................................          (\1\)               200   
Indeno(1,2,3-cd)pyrene......................................................          (\1\)               200   
Isobutyl alcohol............................................................          (\1\)                17   
Isodrin.....................................................................          (\1\)               200   
Isosafrole..................................................................          (\1\)               200   
Kepone......................................................................          (\1\)               400   
m-Dichlorobenzene...........................................................          (\1\)               200   
Methacrylonitrile...........................................................          (\1\)                17   
Methapyrilene...............................................................          (\1\)               200   
Methyl bromide..............................................................          (\1\)                17   
Methyl chloride.............................................................          (\1\)                17   
Methyl ethyl ketone.........................................................          (\1\)                17   
Methyl iodide...............................................................          (\1\)                17   
Methyl methacrylate.........................................................          (\1\)                17   
Methyl methanesulfonate.....................................................          (\1\)               200   
Methyl parathion............................................................          (\1\)               200   
Methylene chloride..........................................................          (\1\)                17   
N-Nitrosodi-n-butylamine....................................................          (\1\)               200   
N-Nitrosomethylethylamine...................................................          (\1\)               200   
N-Nitrosomorpholine.........................................................          (\1\)               200   
N-Nitrosopiperidine.........................................................          (\1\)               200   
N-Nitrosopyrrolidine........................................................          (\1\)               200   
N-Nitrosodiethylamine.......................................................          (\1\)               200   
Naphthalene.................................................................            340                     
Nitrobenzene................................................................          (\1\)               200   
o-Dichlorobenzene...........................................................          (\1\)               200   
o-Toluidine.................................................................          (\1\)               200   
O,O Diethyl O-pyrazinyl phosphoro- thioate..................................          (\1\)               200   
O,O,O-Triethyl phosphorothionate............................................          (\1\)               200   
p-(Dimethylamino)azobenzene.................................................          (\1\)               200   
p-Chloro-m-cresol...........................................................          (\1\)               200   
p-Chloroaniline.............................................................          (\1\)               200   
p-Dichlorobenzene...........................................................          (\1\)               200   
p-Nitroaniline..............................................................          (\1\)               200   
p-Nitrophenol...............................................................          (\1\)               200   
p-Phenylenediamine..........................................................          (\1\)               200   
Parathion...................................................................          (\1\)               200   
Pentachlorobenzene..........................................................          (\1\)               200   
Pentachloroethane...........................................................          (\1\)                17   
Pentachloronitrobenzene.....................................................          (\1\)               200   
Pentachlorophenol...........................................................          (\1\)               200   
Phenacetin..................................................................          (\1\)               200   
Phenol......................................................................          (\1\)               200   
Phorate.....................................................................          (\1\)               200   
Pronamide...................................................................          (\1\)               200   
Pyridine....................................................................          (\1\)               200   
Safrole.....................................................................          (\1\)               200   
Tetrachloroethylene.........................................................          (\1\)                17   
Tetraethyldithiopyrophosphate...............................................          (\1\)               200   
Toluene.....................................................................            110                     
Trichloroethylene...........................................................          (\1\)                17   
Trichlorofluoromethane......................................................          (\1\)                17   
Vinyl Chloride..............................................................          (\1\)               17    
----------------------------------------------------------------------------------------------------------------
\1\ Non-detect.                                                                                                 



          Table 4.--Detection and Detection Limit Values for a Possible Number 6 Fuel Oil Specification         
----------------------------------------------------------------------------------------------------------------
                                                                                Concentration        Maximum    
                                Chemical name                                  limit (mg/kg at   detection level
                                                                               10,000 BTU/lb)        (mg/kg)    
----------------------------------------------------------------------------------------------------------------
Total Nitrogen as N.........................................................           3500     ................
Total Halogens as Cl........................................................             10     ................
Antimony....................................................................              6.5   ................
Arsenic.....................................................................          (\1\)                 0.20
Barium......................................................................          (\1\)                20   
Beryllium...................................................................          (\1\)                 1.0 
Cadmium.....................................................................          (\1\)                 1.0 

[[Page 17488]]

                                                                                                                
Chromium....................................................................          (\1\)                 2.0 
Cobalt......................................................................          (\1\)                 4.1 
Lead........................................................................             30     ................
Manganese...................................................................          (\1\)                 1.0 
Mercury.....................................................................          (\1\)                 0.22
Nickel......................................................................             36     ................
Selenium....................................................................              0.12  ................
Silver......................................................................          (\1\)                 2.0 
Thallium....................................................................          (\1\)                20   
-Naphthylamine.....................................................          (\1\)               640   
,-Dimethylphenethylamine..................................          (\1\)               640   
-Naphthylamine.....................................................          (\1\)               640   
1,1-Dichloroethylene........................................................          (\1\)                20   
1,1,2-Trichloroethane.......................................................          (\1\)                20   
1,1,2,2-Tetrachloroethane...................................................          (\1\)                20   
1,2-Dibromo-3-chloropropane.................................................          (\1\)                20   
1,2-Dichloroethylene (cis- or trans-).......................................          (\1\)                20   
1,2,3-Trichloropropane......................................................          (\1\)                20   
1,2,4-Trichlorobenzene......................................................          (\1\)               640   
1,2,4,5-Tetrachlorobenzene..................................................          (\1\)               640   
1,3,5-Trinitrobenzene.......................................................          (\1\)               640   
1,4-Dichloro-2-butene (cis- or trans-)......................................          (\1\)                20   
1,4-Naphthoquinone..........................................................          (\1\)               640   
2-Acetylaminofluorene.......................................................          (\1\)               640   
2-Chloroethyl vinyl ether...................................................          (\1\)                20   
2-Chloronaphthalene.........................................................          (\1\)               640   
2-Chlorophenol..............................................................          (\1\)               640   
2-Piccoline.................................................................          (\1\)               640   
2,3,4,6-Tetrachlorophenol...................................................          (\1\)               640   
2,4-Dichlorophenol..........................................................          (\1\)               640   
2,4-Dimethylphenol..........................................................          (\1\)               640   
2,4-Dinitrophenol...........................................................          (\1\)               640   
2,4-Dinitrotoluene..........................................................          (\1\)               640   
2,4,5-Trichlorophenol.......................................................          (\1\)               640   
2,4,6-Trichlorophenol.......................................................          (\1\)               640   
2,6-Dichlorophenol..........................................................          (\1\)               640   
2,6-Dinitrotoluene..........................................................          (\1\)               640   
3-3-Dimethylbenzidine.......................................................          (\1\