[Federal Register Volume 59, Number 20 (Monday, January 31, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-1556]
[[Page Unknown]]
[Federal Register: January 31, 1994]
_______________________________________________________________________
Part III
Environmental Protection Agency
_______________________________________________________________________
40 CFR Parts 9 and 68
List of Regulated Substances and Thresholds for Accidental Release
Prevention and Risk Management Programs for Chemical Accident Release
Prevention; Final Rule and Notice
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 9 and 68
[FRL-4828-6]
List of Regulated Substances and Thresholds for Accidental
Release Prevention; Requirements for Petitions Under Section 112(r) of
the Clean Air Act as Amended
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: The Environmental Protection Agency (EPA) is promulgating the
list of regulated substances and thresholds required under section
112(r) of the Clean Air Act as amended. The list is composed of three
categories: A list of 77 toxic substances, a list of 63 flammable
substances, and explosive substances with a mass explosion hazard as
listed by the United States Department of Transportation (DOT).
Threshold quantities are established for toxic substances ranging from
500 to 20,000 pounds. For all listed flammable substances the threshold
quantity is established at 10,000 pounds. For explosive substances the
threshold quantity is established at 5,000 pounds. The list and
threshold quantities will identify facilities subject to chemical
accident prevention regulations promulgated under section 112(r) of the
Clean Air Act as amended; a proposed regulation for such requirements
has been published in the Federal Register on October 20, 1993,
entitled Risk Management Programs for Chemical Accidental Release
Prevention. EPA is also promulgating in this regulation the
requirements for the petition process for additions to, or deletions
from, the list of regulated substances. EPA is deferring action on a
proposed exemption from regulation for listed flammable substances when
used solely for facility consumption as fuel. For a document relating
to the proposed exemption, see a supplemental notice published
elsewhere in this issue.
DATES: This rule is effective March 2, 1994.
ADDRESSES: Docket: Supporting information used in developing both the
proposed and the final rule is contained in Docket No. A-91-74. The
docket is available for public inspection and copying from 8 a.m. to 4
p.m., Monday through Friday, at the EPA's Air Docket Section, Waterside
Mall, room M 1500, U.S. Environmental Protection Agency, 401 M Street,
SW., Washington, DC 20460. A reasonable fee may be charged for copying.
FOR FURTHER INFORMATION CONTACT: Vanessa Rodriguez, Chemical Engineer,
(202) 260-7913, Chemical Emergency Preparedness and Prevention Office,
Mailcode 5101, U.S. Environmental Protection Agency, 401 M Street, SW.,
Washington, DC 20460, or the Emergency Planning and Community Right-to-
Know Hot Line at 1-800-535-0202.
SUPPLEMENTARY INFORMATION: The information presented in this preamble
is organized as follows:
I. Introduction
A. Statutory Authority
B. Background
II. Clean Air Act Amendments of 1990
A. Prevention of Accidental Releases
B. List of Substances and Thresholds; Petitions for Additions
and Deletions
1. Legislative Requirements
2. Summary of Proposed Rule
III. Public Participation
IV. Discussion of Comments and Major Regulatory Changes
A. List of Substances and Threshold Quantities
1. Toxic Substances
a. Listing Criteria
b. Specific Substances
c. Other List Options Considered
d. Threshold Quantities
e. Other Threshold Quantity Options Considered
2. Flammable Substances
3. Explosives
B. Threshold Determination
1. Basis for Threshold Determination
2. Mixture Exemption
a. Toxic Substances
b. Flammable Substances
c. Explosive Substances
3. Other Threshold Exemptions
C. Petition Process
D. Definitions
E. Exemptions
F. Scope
V. Summary of Provisions of the Final Rule
VI. Required Analyses
A. E.O. 12866
B. Regulatory Flexibility Act
C. Paperwork Reduction Act
D. Display of OMB Control Numbers
I. Introduction
A. Statutory Authority
This final rule is being issued under sections 112(r) and 301 of
the Clean Air Act (CAA or Act) as amended (42 U.S.C. 7412(r), 7601).
B. Background
Public awareness of the potential danger from accidental releases
of hazardous chemicals has increased over the years as serious chemical
accidents have occurred around the world (e.g., the 1974 explosion in
Flixborough, England, and the 1976 release of dioxin in Seveso, Italy).
Public concern intensified following the 1984 release of methyl
isocyanate in Bhopal, India, which killed more than 2,000 people living
near the facility. A subsequent release from a chemical facility in
Institute, West Virginia, sent more than 100 people to the hospital and
made Americans aware that such accidents can and do happen in the
United States.
In response to this public concern and the hazards that exist, the
U.S. Environmental Protection Agency (EPA) began its Chemical Emergency
Preparedness Program (CEPP) in 1985, as part of the Agency's Air Toxics
Strategy. CEPP was a voluntary program to encourage state and local
authorities to identify hazards in their areas and to plan for chemical
emergency response actions. In 1986, Congress adopted many of the
elements of CEPP in the Emergency Planning and Community Right-to-Know
Act of 1986 (EPCRA), also known as Title III of the Superfund
Amendments and Reauthorization Act of 1986 (SARA Title III). EPCRA
requires states to establish state and local emergency planning groups,
namely the State Emergency Response Commissions (SERCs) and the Local
Emergency Planning Committees (LEPCs), to develop emergency response
plans for each community. EPCRA requires facilities to provide
information on the hazardous chemicals they have on-site; the
information collected is available to the public through the SERC/LEPC
structure. This information forms the foundation of both the emergency
response plans and the public-industry dialogue on risks and risk
reduction.
Congress required EPA, under EPCRA (SARA Title III) section 305(b),
to conduct a review of emergency systems to monitor, detect, and
prevent chemical accidents. The final report to Congress, Review of
Emergency Systems (EPA, 1988), concluded that the prevention of
accidental releases requires an integrated approach that considers
technologies, operations, and management practices. The report
emphasized the importance of management commitment to safety.
In 1986, EPA established a chemical accident prevention program to
collect information on chemical accidents and work with other groups to
increase knowledge of prevention practices and encourage industry to
improve safety at facilities. Under this program, EPA developed its
Accidental Release Information Program (ARIP) to collect data on the
causes of chemical accidents and the steps facilities take to prevent
recurrences. EPA also developed a program for conducting chemical
safety audits at facilities. Through the audit program, EPA
headquarters and regional staff, as well as state and local officials,
learned about integrated approaches to process safety from facilities.
EPA has also worked with trade associations, professional
organizations, labor, environmental groups, and other Federal agencies
to determine how best to reach smaller operations, which the section
305(b) study indicated are less aware of risks than larger facilities.
EPA has also been an active participant in international efforts
related to chemical accident prevention, particularly through the
Organization for Economic Cooperation and Development (OECD), which has
held five international workshops from 1989 through 1991 to discuss
issues related to accident prevention, preparedness, and response, and
has developed guidelines for member countries.
In addition to EPA's work in this area, other agencies and states
have developed programs related to chemical accident prevention. The
Occupational Safety and Health Administration (OSHA) promulgated a
final rule on chemical process safety management amending 29 CFR
1910.109 and adding 29 CFR 1910.119 (57 FR 6356, February 24, 1992) as
required under section 304 of the Clean Air Act Amendments of 1990 (CAA
Amendments). Four states--New Jersey, California, Delaware, and
Nevada--have operational risk management programs. Additional states
have begun to address accidental release prevention as part of their
air toxics program development.
Professional and trade organizations have also developed programs
in this area. For example, the Center for Chemical Process Safety of
the American Institute of Chemical Engineers has published guidance on
the management of chemical process safety. The Chemical Manufacturers'
Association has adopted a Responsible CareTM program, which all
members must comply with to maintain membership. The American Petroleum
Institute has developed a similar program, Management of Process
Hazards; Recommended Practice 750 (RP 750), for its members. In 1982,
the European Community adopted the Seveso Directive (82/501/EEC, as
amended), which requires facilities handling certain chemicals to
develop a safety report that is similar to a risk management plan.
II. Clean Air Act Amendments of 1990
A. Prevention of Accidental Releases
In the CAA Amendments, signed into law on November 15, 1990,
Congress added subsection (r) to CAA section 112 for the prevention of
chemical accidents. The goals of the chemical accident prevention
provisions are to focus on chemicals that pose a significant hazard to
the community should an accident occur, to prevent their accidental
release and to minimize the consequences of such releases.
Section 112(r) of the CAA has a number of provisions. Under section
112(r) owners and operators of stationary sources who produce, process,
handle, or store substances listed under section 112(r)(3) or any other
extremely hazardous substances have a general duty to initiate specific
activities to prevent and mitigate accidental releases. The general
duty requirements apply to stationary sources regardless of the
quantity of substances managed at the facility. Activities such as
identifying hazards which may result from accidental releases using
appropriate hazard assessment techniques; designing, maintaining and
operating a safe facility; and minimizing the consequences of
accidental releases if they occur would be essential activities to be
taken as necessary to satisfy the general duty requirements. As a
matter of business practice, owners and operators of these stationary
sources have a duty to conduct these activities under section 112(r) in
the same manner and to the same extent as an employer's duties under
OSHA's general duty clause in section 654 of title 29 of the United
States Code.
Section 112(r)(3) of the CAA requires EPA to promulgate an initial
list of at least 100 substances (``regulated substances'') that are
known to cause, or may be reasonably anticipated to cause, death,
injury, or serious adverse effects to human health or the environment
if accidentally released. EPA is required to set threshold quantities
for each listed substance. Under CAA section 112(r)(7), the Act
requires EPA to promulgate reasonable regulations and appropriate
guidance to provide for the prevention and detection of accidental
releases and for responses to such releases. The accident prevention
regulations will apply to stationary sources that have present more
than a threshold quantity of a regulated substance. These regulations
shall address, as appropriate, the use, operation, repair, and
maintenance of equipment to monitor, detect, inspect, and control
releases, including training of personnel in the use and maintenance of
equipment or in the conduct of periodic inspections. The regulations
shall include requirements for the development and submission of Risk
Management Plans (RMPs) by regulated sources. The RMP shall include a
hazard assessment, a prevention program, and an emergency response
program. The proposed rule for accident prevention, Risk Management
Programs for Chemical Accidental Release Prevention, was published on
October 20, 1993 (58 FR 54190).
The Act establishes a Chemical Safety and Hazard Investigation
Board to investigate (or cause to be investigated) chemical accidents
at facilities and recommend to Congress, Federal, state, local
authorities, and the public actions that can be taken to improve
chemical safety. Under the Act, EPA is authorized to conduct studies
related to accidental releases, including research on hazard
assessments, hydrogen fluoride, and air dispersion modeling. A report
to Congress on hydrogen fluoride was completed and published by the
Agency in September 1993, entitled Hydrogen Fluoride Study, Report to
Congress, section 112(n)(6) of the Clean Air Act as Amended.
The Clean Air Act also addressed the approval of state programs and
delegation of Federal authorities for all section 112 requirements in
section 112(l). Thus, state Accidental Release Prevention programs are
approved through the authorities in section 112(l). The approval
provisions of section 112(l)(5) include a determination that: A state
program contains the authorities to assure compliance by all sources
within the state with each applicable standard, regulation, or
requirement; adequate resources are available to implement the program;
an expeditious implementation schedule is in place to ensure that
affected sources achieve compliance; and the state program is otherwise
in compliance with the objectives of the Act and guidance published
under section 112(l)(2).
The Agency promulgated a final rule in November 1993 which
addresses the approval requirements of section 112(l) entitled Approval
of State Programs and Delegation of Federal Authorities. These
requirements can be found in 40 CFR part 63--Subpart E. Section 63.95
specifically address the required components of an accidental release
prevention program. The Agency is currently working on developing
further guidance to states in regard to the development of an
accidental release prevention program.
Under section 304 of the CAA Amendments OSHA was required to
promulgate a chemical process safety management standard to protect
employees from hazards associated with accidental releases of highly
hazardous chemicals in the workplace. OSHA promulgated a final rule
amending 29 CFR 1910.109 and adding 29 CFR 1910.119 (57 FR 6356,
February 24, 1992) that requires a chemical process safety management
(PSM) program for any process involving a highly hazardous chemical at
or above a specified threshold quantity. The rule applies to a list of
highly hazardous toxic and reactive substances at particular threshold
quantities, flammable liquids or flammable gases in quantities of
10,000 pounds or more and to the manufacture of explosives and
pyrotechnics.
B. List of Substances and Thresholds; Petitions for Additions and
Deletions
1. Legislative Requirements
The Act requires EPA to promulgate an initial list of at least 100
substances that, in the event of an accidental release, are known to
cause or may reasonably be anticipated to cause death, injury, or
serious adverse effects to human health or the environment. An
accidental release is defined under CAA section 112(r)(2)(A) as ``an
unanticipated emission * * * into the ambient air from a stationary
source.'' In developing this list, EPA was required to consider, but
was not limited to, the list of extremely hazardous substances (EHSs)
promulgated under EPCRA (SARA Title III) section 302.
Congress listed the following 16 substances to be included in the
initial list (the Chemical Abstracts Service (CAS) Registry number is
provided in parentheses):
Chlorine (7782-50-5)
Ammonia and anhydrous ammonia (7664-41-7)
Methyl chloride (74-87-3)
Ethylene oxide (75-21-8)
Vinyl chloride (75-01-4)
Methyl isocyanate (624-83-9)
Hydrogen cyanide (74-90-8)
Hydrogen sulfide (7783-06-4)
Toluene diisocyanate, represented by:
--Toluene 2,4-diisocyanate (584-84-9)
--Toluene 2,6-diisocyanate (91-08-7)
--Toluene diisocyanate, unspecified isomer (26471-62-5)
Phosgene (75-44-5)
Bromine (7726-95-6)
Anhydrous hydrogen chloride (7647-01-0)
Hydrogen fluoride (7664-39-3)
Anhydrous sulfur dioxide (7446-09-5), and
Sulfur trioxide (7446-11-9)
No air pollutant for which a national primary ambient air quality
standard has been established may be included on the list, with the
exception of anhydrous sulfur dioxide and sulfur trioxide, which must
be included. No substances regulated under Title VI of the Act as
amended may be included on the list. Title VI covers ozone depleters,
primarily chlorofluorocarbons (CFCs) and halons. The Act requires EPA
to review, and if necessary revise, the list of regulated substances
under section 112(r) at least every five years. EPA may also review and
if necessary revise the list as a result of petitions. EPA is required
to develop procedures for petitions to the Agency for the addition of
substances to, and deletion of substances from, the list; these
petition procedures are to be consistent with those applicable to the
list of hazardous air pollutants found in CAA Amendments section
112(b).
2. Summary of Proposed Rule
On January 19, 1993 (58 FR 5102), EPA proposed a list of 100 toxic
substances and threshold quantities, a list of 62 flammable substances
(gases and volatile liquids) with threshold quantities of 10,000
pounds, and commercial explosives defined by the Department of
Transportation (DOT) as Division 1.1 (explosives with mass explosion
hazard) with a threshold quantity of 5,000 pounds. EPA also proposed
requirements for a petition process to add or delete chemicals from the
list.
Toxic substances were included on the list based on their toxicity,
physical state, vapor pressure, production volume, and accident
history. Toxicity criteria used to identify chemicals as extremely
hazardous substances (EHSs) under EPCRA were used as criteria for the
proposed list. The acute toxicity criteria are:
(a) Inhalation LC50 0.5 milligrams per liter of
air (for exposure time 8 hours), or
(b) Dermal LD50 50 milligrams per kilogram of body
weight, or
(c) Oral LD50 25 milligrams per kilogram of body
weight where LC50 is the median concentration in air at which 50
percent of the test animals died, and LD50 is the median lethal
dose that killed 50 percent of the test animals. In the absence of
LC50 or LD50 data, LCLo or LDLo data were used for
listing, where LCLo is the lethal concentration low, or lowest
concentration in air at which any of the test animals died, and
LDLo is the lethal dose low, or the lowest concentration at which
any of the test animals died. Additional substances on the EHS list
meet the secondary EHS toxicity criteria in light of production volume
(see appendix B of EPA's Technical Guidance for Hazards Analysis,
December 1987, which is in the docket for this rulemaking). A vapor
pressure criterion of 0.5 millimeters of mercury (mm Hg) was used as a
baseline, based on the vapor pressure of toluene diisocyanate, a
substance mandated for the initial list by Congress; toxic gases and
liquids with a vapor pressure of 0.5 mm Hg or higher under ambient
conditions were considered for listing. Only toxic chemicals in
commercial production, verified through EPA's Toxic Substances Control
Act (TSCA) Chemical Inventory, were included on the list. By applying
these criteria to the 360 chemicals on the EPCRA EHS list, the Agency
identified 87 potential regulated substances for the CAA Amendments
section 112(r) list. The Agency also looked at other data sources
(including the OSHA highly hazardous chemical list) to identify 9 more
substances for the section 112(r) list. Four additional substances were
identified for listing based on a combination of toxicity, high
production volume, and history of accidents involving death or injury.
Threshold quantities were set for toxic substances based on a ranking
method that considers toxicity and volatility of the chemicals. EPA
assigned identical thresholds to chemicals with similar ranking scores,
ranging from 500 pounds to 10,000 pounds.
Flammable gases and volatile flammable liquids were included on the
list based on the flash point and boiling point criteria used by the
National Fire Protection Association (NFPA) for its highest
flammability hazard ranking (flash point below 73 deg.F (22.8 deg.C)
and boiling point below 100 deg.F (37.8 deg.C)) (Fire Protection Guide
on Hazardous Materials, 1984, 8th edition). Only flammable substances
in commercial production were listed. The threshold quantity for
flammable substances was set at 10,000 pounds, based on the potential
for a vapor cloud explosion.
Explosives in Division 1.1 were proposed for listing based on their
potential to detonate. The threshold quantity for explosives was set at
5,000 pounds because a detonation of this quantity could yield blast
wave overpressures of 3.0 pounds per square inch (psi) at a distance of
100 meters from the blast site and could have potentially lethal
effects in the community beyond the fenceline.
EPA proposed to apply the threshold quantity to the maximum total
quantity of a substance in a process. This definition would apply to
the maximum total quantity, at any one time, in a single vessel, in a
group of interconnected vessels or in several vessels that could
potentially be involved at one time in an accidental release.
Substances in mixtures would be exempted from the threshold
determination if they represent less than one percent of the mixture by
weight. EPA also proposed to exempt substances if (1) they are part of
articles; (2) if they are used as structural components; (3) if they
are used for janitorial maintenance; or (4) if they are found in
consumer products, process water, or in water or air from the
environment or municipal sources. Activities in laboratories were also
proposed for exemption. In addition, an exemption was proposed for
flammable substances present at a facility to be used solely for
consumption as fuel at the facility.
The Agency also proposed requirements for petitions to add or
delete regulated substances under section 112(r). The Agency proposed
to establish that the burden of proof be on the petitioner to
demonstrate that the criteria for addition and deletion are met. Basic
administrative and documentation requirements for petitions were also
included in the proposal.
III. Public Participation
A hearing was held on the proposed rule in the EPA Auditorium, 401
M Street, SW., Washington DC, on Tuesday, April 12, 1993. The hearing
was held to provide interested parties the opportunity for oral
presentation of data, views, or arguments concerning the proposed rule.
This hearing was open to the public; a transcript of the public hearing
is available in the docket. A total of 272 letters were received during
the public comment period on the proposed rule (an additional 18 were
received after the close of the public comment period); copies of all
comment letters received are available for public inspection in the
docket. A response to comments document, entitled Proposed List of
Substances and Thresholds for Accidental Release Prevention: Summary
and Response to Comments, includes a summary of comments received and
the Agency's responses; the document is available in the docket.
IV. Discussion of Comments and Major Regulatory Changes
This portion of the preamble discusses comments on major issues
received on the proposed list and thresholds rule and the principal
regulatory changes made in the final rule in response to public
comments. Included in the discussion is the rationale for these changes
and the Agency action on the comments. Where the proposed regulation
has not been changed in the final rule, the Agency continues to rely on
the rationale provided in the proposal notice, supplemented as
appropriate by additional discussion in this preamble and in the
response to comments document.
A. List of Substances and Thresholds
The list of substances and thresholds promulgated today identifies
sources that are subject to accident prevention regulations promulgated
under section 112(r)(7) of the Act. The list of substances is intended
to focus accidental release prevention efforts on those stationary
sources and substances that pose the most significant risks to the
community. These risks may be established either by the potential of
the chemical to cause harm (the inherent hazards and physical/chemical
properties), known incidents (accident history), or a combination
thereof. EPA strongly emphasizes that the substances promulgated in
today's listing are not the only substances that may pose a threat to
communities upon release. There are large numbers of compounds and
mixtures in commerce in the U.S. that in specific circumstances could
be considered dangerous to human health or the environment; however, it
would not be feasible to include all such substances and circumstances.
This list should serve to focus prevention efforts and is not a list of
all substances that could be considered for accident prevention.
Similarly, the threshold quantities established today may not always
represent a level below which no hazard exists. Although stationary
sources will be required to comply with the accidental release
prevention regulations under section 112(r)(7)(B) only if they have
listed substances in quantities exceeding the threshold quantity, it
does not mean that these substances in smaller quantities represent no
potential hazard to the community in certain circumstances. In support
of this principle Congress included general duty provisions under
section 112(r)(1) of the Act.
Several commenters objected to the listing of classes of substances
such as explosives or particular substances such as various flammable
natural gases because these commenters claimed that categorizing these
chemicals as regulated substances would also make these chemicals
subject to the general duty clause of section 112(r)(1), and that
without such listing these chemicals would be outside the scope of
section 112(r)(1). The general duty provision in section 112(r)(1)
applies to ``any substance listed pursuant to section 112(r)(3) or any
other extremely hazardous substance.'' The Agency believes the scope of
substances covered by section 112(r)(1) is not affected by this
rulemaking except that by including a substance on the regulated
substance list, the Agency unambiguously specifies that the general
duty provisions apply to such chemicals. The plain language of section
112(r)(1) applies not only to the regulated substances listed today but
also to ``any other extremely hazardous substance.''
In discussing nearly identical language in the Senate's Clean Air
Act Amendments bill of 1989, the Environment and Public Works Committee
expressed the intent that the term ``extremely hazardous substance''
would include not only listed substances under the accident prevention
provisions and extremely hazardous substances under EPCRA (SARA Title
III) section 302 but also ``other agents which may or may not be listed
or otherwise identified by any Government agency which may as the
result of short-term exposures associated with releases to the air
cause death, injury or property damage'' (Senate Committee on
Environment and Public Works, Clean Air Act Amendments of 1989, Senate
Report No. 228, 101st Congress, 1st Session 211 (1989)--``Senate
Report''). Regardless of whether a substance is listed under today's
rule, the general duty to identify and assess hazards associated with
accidental releases (as defined in section 112(r)(2)), to design and
maintain a facility to prevent such releases, and to minimize the
consequences of such releases that do occur, extends to owners and
operators of any facility that may cause such impacts due to short-term
exposures. As the Senate makes clear, ``the release of any substance
which causes death or serious injury because of its acute toxic effect
or as a result of an explosion or fire or which causes substantial
property damage by blast, fire, corrosion or other reaction would
create a presumption that such substance is extremely hazardous.''
Senate Report at 211. No revision to the list promulgated today negates
the applicability of the general duty provisions.
1. Toxic Substances
a. Listing criteria. Several commenters suggested that EPA modify
its listing criteria, largely so that EPA's list would be more
consistent with OSHA's list of Highly Hazardous Substances for its
Process Safety Management Standard, but also because commenters
believed EPA's list includes some chemicals that do not pose the
greatest hazards to the public. Some commenters suggested the proposed
0.5 mm Hg vapor pressure cut off was too low. Others suggested an
alternative method of choosing the list of toxics, namely the
``Substance Hazard Index''. Several commenters also objected to EPA's
use of accident history as a criterion for listing substances. EPA's
proposed toxics list was based on the EHS list under SARA Title III,
with additional consideration of the vapor pressures and accident
histories for each substance. The proposed list included 50 toxic
substances that are not listed by OSHA.
Substance Hazard Index: Some commenters suggested replacing EPA's
proposed listing criteria with another method labeled the ``Substance
Hazard Index'' (SHI). The SHI is the ratio of a substance's vapor
pressure to its acute toxicity; all substances would be ranked by their
SHI and a cut-off would need to be selected to determine the substances
to be listed. An SHI value of 1,000 was suggested by commenters as a
cut-off, but commenters did not provide a technical basis, or any other
rationale, for why this cut-off was selected. The SHI value of 1,000
would derive a list of toxic substances that more closely approximates
OSHA's PSM list than EPA's proposed list; provided that the Agency
considers only those substances initially proposed for listing as
toxics.
EPA generally disagrees with the comments concerning the use of the
SHI as a listing criterion. The Agency had considered this approach
during the proposed rule development, but decided not to include it as
an alternate listing methodology option. EPA instead considered
toxicity and vapor pressure separately in identifying chemicals for
listing; the SHI combines these factors. EPA believes that using
separate toxicity and vapor pressure criteria is a more valid method of
identifying chemical candidates for listing. Both EPA's method and the
SHI approach consider properties related to the severity of acute
health effects (toxicity) and the likelihood of accidental releases of
the substances (volatility), as required by the Act. However, as
required by the Act, EPA's approach is based on the list of EHSs as a
starting point for identification of toxic substances (see Senate
Report at 218; listing factors used in EHS list are appropriate for
accidental release program). EPA's approach limits toxic chemicals to
those meeting the acute toxicity criteria for the EHS list and then
applies a vapor pressure cut-off. The SHI approach does not include
specific toxicity or vapor pressure cut-offs but instead specifies a
cut-off value for a factor combining toxicity and vapor pressure. To
identify all chemicals meeting the specific SHI cut-off of 1,000 as
recommended by commenters, chemicals with a much wider range of
toxicity than those represented by the EHSs would have to be
considered. Chemicals that are far less toxic than the EHSs would be
potentially included, improperly characterizing the risk associated
with them. Moreover, EPA does not believe the SHI method has been
systematically applied to all substances for development of any current
chemical list. The state of Delaware used the SHI approach to develop a
list of substances for its risk management regulation; the SHI
methodology was applied to existing lists of substances identified by
use of toxicity criteria and not all substances. The Agency considers
the SHI to be more appropriate for determining the relative ranking of
substances in an already established list. The Agency's threshold
quantity methodology for listed toxics is similar on the toxicity/
volatility ranking principle; it differs from the SHI in that the vapor
pressure is only part of the factor used to account for the potential
dispersability of the listed substances. For these reasons, the Agency
will not adopt the SHI criteria for listing toxic substances.
Acute Toxicity Criteria: Commenters generally supported EPA's
consideration of acute toxicity hazards as a basis for listing toxic
substances under section 112(r). Some commenters, however, recommended
other measures of toxicity, such as the Emergency Response Planning
Guidelines (ERPGs) developed by the American Industrial Hygiene
Association, or data developed by the National Academy of Sciences
among others. The Agency recognizes the value of these other measures
and guidelines for purposes of emergency preparedness and prevention
activities. However, these measures are consensus exposure levels
judged by the developing organizations to represent concentrations
above which there may be serious irreversible health effects, or death,
as a result of a single exposure for a relatively short period of time.
In addition, the methodology for most of these measures is still in the
developmental stages, with recommended guidelines or acute exposure
levels presently available only for a limited number of potentially
hazardous substances. The Agency believes using acute toxicity data as
proposed is more appropriate for the review and selection of hazardous
substances for listing under section 112(r) because acute toxicity data
directly reflects results of valid mammalian testing and thus is more
objectively verifiable than judgmental standards.
Concerns were also expressed about the Agency's focus on acute
toxicity rather than on chronic toxicity effects as a basis for
listing. Some commenters also opposed the Agency's consideration of
acute exposures by the dermal and oral routes. EPA believes that
chemical accident prevention efforts should focus on those chemicals
that, because of their inherent toxicity, are most likely to cause
immediate severe, irreversible health effects following exposures
during an accidental release. Consequently, for purposes of this
rulemaking, the Agency is primarily interested in substances that are
acutely toxic, rather than in substances that could generate a future
health effect after repeated long term or chronic exposures.
Furthermore, acute toxicity and lethality data are often readily
available and the most commonly reported information generated by
animal toxicity testing. A greater number of potentially hazardous
substances can therefore be screened on the same basis using these
values. For purposes of this rule, the listed toxic substances are
expected to rapidly become airborne, thus human exposure by the
inhalation route is of primary concern. The Agency believes that using
data on oral and dermal acute lethality, in addition to inhalation
lethality, is appropriate for this listing.
Vapor Pressure Cut-Off: Other commenters suggested that EPA should
use a higher vapor pressure level as a listing criterion. EPA's vapor
pressure criterion of 0.5 mm Hg was based on the properties of toluene
diisocyanate, a substance with relatively low volatility, which was
mandated for the initial list by Congress. Commenters noted that
Congress listed toluene diisocyanate because it has been involved in
accidents, not because of its properties, and that its properties do
not necessarily provide a valid basis for EPA's vapor pressure
criterion. Several commenters suggested a vapor pressure of 20 mm Hg
(18 mm Hg is the approximate vapor pressure of water) but did not
provide a basis for choosing this or any other vapor pressure
criterion.
EPA has considered the comments concerning the proposed vapor
pressure criterion of 0.5 mm Hg and generally agrees that this low
vapor pressure level may lead to an overly conservative listing of
chemicals that pose a relatively lower potential for air releases. EPA
has decided to set the vapor pressure criterion at the higher level of
10 mm Hg. In selecting this new vapor pressure cut-off, the Agency
examined the substances on the proposed list that have vapor pressures
of less than 10 mm Hg and compared the rate of volatilization expected
in a large release to the rate expected for substances with a vapor
pressure greater than 10 mm Hg. As expected, volatilization rates
increase with increasing vapor pressure and increasing pool sizes. The
Agency believes that a timely facility response after the onset of an
accidental release will likely limit the amount that could volatilize
for substances with vapor pressures lower than 10 mm Hg, thereby
reducing the potential public or off-site impact. The Agency believes
that a greater amount of substances with vapor pressures above 10 mm Hg
is likely to be volatilized and released, even after a timely facility
response occurs, potentially causing off-site impacts. The Agency also
reviewed accident history and production volume information on the
substances that would be delisted at this vapor pressure. This review
has led the Agency to conclude that the accident histories or
production volumes associated with the delisted substances do not
warrant their listing under this rulemaking at this time. The Agency
believes that this revised vapor pressure criterion focuses the list on
chemicals that present a greater potential for accidental release than
would a list using a 0.5 mm Hg criterion.
The new vapor pressure criterion will drop from the list some
chemicals that may have a lower likelihood of accidental release to
air. Using the new vapor pressure criterion, the following 18 chemicals
proposed for listing (shown with their CAS Registry numbers) will not
be included in the list promulgated today:
Acetone cyanohydrin (75-86-5)
Aniline (62-53-3)
Antimony pentafluoride (7783-70-2)
Benzal chloride (98-87-3)
Benzenamine, 3-(trifluoromethyl)- (98-16-8)
Benzotrichloride (98-07-7)
Benzyl chloride (100-44-7)
Benzyl cyanide (140-29-4)
Chloroethanol (107-07-3)
Dichloroethyl ether (111-44-4)
Dimethyl phosphorochloridothioate (2524-03-0)
Formaldehyde cyanohydrin (107-16-4)
Hydrogen peroxide (concentration > 52%) (7722-84-1)
Lactonitrile (78-97-7)
Pyridine, 2-methyl-5-vinyl- (140-76-1)
Thiophenol (108-98-5)
Trans-1,4-dichlorobutene (110-57-6)
Trichloroethylsilane (115-21-9)
EPA will be reevaluating the list periodically and as a result of
petitions. If additional information is submitted on the accident
history or production volume of these substances, EPA may list these
substances at a later time. In addition, these substances, as well as
any other extremely hazardous substance, are subject to the section
112(r) general duty clause.
Accident History: The Agency disagrees with several commenters who
claimed that the Agency lacked authority to list substances based on
accident history. The accident history associated with the use of a
substance, in combination with toxicity, physical/chemical properties,
and production volume considerations, is a permissible basis for the
Administrator to list substances under section 112(r). Data from
recorded accidents relate to each of the factors identified in section
112(r)(4). Such data can provide information on the severity of impacts
when impacts occur, as well as on the likelihood and magnitude of
exposure. Substances that ``are known to cause * * * death, injury, or
serious adverse effects on human health or the environment'' may be
included on the list under section 112(r)(3). It would be a strained
reading of the statute to say the Administrator must ignore documented
accidental releases of substances in deciding which chemicals shall be
the focus of the accidental release prevention program.
The listing criteria established for toxic substances considers not
only acute toxicity, but also physical/chemical properties (physical
state, vapor pressure), and accident history. Several commenters argued
that in analyzing accident histories EPA should not consider: (1)
Transportation accidents; (2) accidents not involving death and/or
injuries; (3) accidents involving fires and explosions; (4) accidents
involving reactions with other chemicals; and (5) accidents involving
elevated temperatures and pressures. The Agency disagrees with these
comments. Accident history may indicate, beyond vapor pressure or other
physical/chemical properties, unique qualities or circumstances that
warrant accident prevention efforts. Evidence from transportation
accidents may indicate the potential for airborne releases. For
example, chemicals may be supplied in containers, such as tank cars,
holding the chemical in similar conditions to storage conditions at
stationary source. A failure of a container while in transit may
indicate the potential for release while at a fixed location, since it
may be stored under similar conditions. Quantities of chemicals are
also commonly held at facilities for some period of time in trucks,
tank cars, and other shipping containers. Accidents that did not result
in off-site deaths or injuries may still indicate the serious potential
for off-site impacts; e.g., evacuations may indicate that there was
concern that people could suffer adverse effects from exposure.
Furthermore, other effects, such as environmental damage, are
appropriate to consider as well. While the factors to be considered
under section 112(r)(4) do not specifically direct EPA to consider
environmental effects, section 112(r)(3) directs the Administrator to
consider ``substances which pose the greatest risk of causing * * *
serious adverse effects to * * * the environment from accidental
releases''. As noted at several points in this preamble, EPA believes
that its decision to consider reported accidental releases involving
fire and explosions as events of concern is supported by both the
statute and legislative history. See also 136 Congressional Record
S16992 (daily ed., Oct. 27, 1990) (statement of Senator Reid addressing
the explosion in Henderson, Nevada); 136 Congressional Record H12931
(daily ed., Oct. 26, 1990) (statement of Representative Barton
addressing releases from burning material); H.R. Conf. Rep. No. 952,
101st Congress, 2nd sess., 340 (1990) (Board to investigate fires and
explosions). It may also be appropriate to consider chemical reactions
with common materials such as water; e.g., it may be important to
consider whether the reaction of an acid with water, producing heat,
could lead to formation of an acid vapor or mist (the Bhopal accident
involved a reaction of methyl isocyanate with water, generating heat).
Accidents resulting from conditions of elevated temperatures and
pressures in chemical processes may provide important information
regarding the potential for accidental releases having an effect off-
site.
The legislative history of section 112(r) contains extensive
discussion of historical accidents and accident history data to support
the need for enacting section 112(r) and the particular provisions
included in the legislation. See 136 Congressional Record H12940 (daily
ed., Oct. 26, 1990) (statement of Representative Richardson); 136
Congressional Record S16921, S16925-26 (daily ed., Oct. 27, 1990)
(statement of Senator Durenberger); 136 Congressional Record S16979
(daily ed., Oct. 27, 1990) (statement of Senator Baucus). Incidents
such as the explosion in Henderson, Nevada and the releases documented
in the Acute Hazardous Events database, as well as statistics
concerning the number of releases and evacuations were seen as
demonstrating the need for an accident prevention program. See H.R.
Rep. No. 490, 101st Congress, 2nd sess., 154-157 (1990); Senate Report
at 211-221. The Agency will continue to consider accident history, in
conjunction with acute toxicity and vapor pressure, to determine which
substances need to be listed under section 112(r), and will consider
these same elements in any revisions to the list promulgated today.
When determining whether to list a substance based on its accident
history, the Agency will analyze and explain the relevance of the
accident history to the potential for a stationary source to
accidentally release the substance.
b. Specific substances. Sulfuric acid, phenol, parathion, and
nitrobenzene, proposed to be listed because of accident history, were
the focus of a number of comments. As stated above, the Agency believes
that accident history, as well as toxicity, physical/chemical
properties, and current commercial production volume, are all
appropriate elements to be considered in determining the substances to
be listed. The Agency reserves the flexibility to consider the listed
substances in light of a combination of, or all of these criteria
elements. Accident history was targeted by several commenters as not
being a valid criteria to use in listing these substances. As discussed
above, the Agency disagrees. The Agency has listed substances that meet
two or three elements of the criteria only; e.g., there are acutely
toxic substances listed that meet the high vapor pressure
considerations but have no accident history associated with them. By
the same token, the Agency also believes that commercially produced
substances that meet the acute toxicity criterion and have an accident
history, still could present a high potential for an impact beyond the
fenceline even though they do not meet the vapor pressure
consideration.
A number of commenters objected to the inclusion of sulfuric acid
on the list of substances, noting that because of its high boiling
point and low vapor pressure under ambient conditions, it is unlikely
to become airborne in a release. EPA recognizes that sulfuric acid does
not meet the vapor pressure criterion. EPA originally proposed for
listing sulfuric acid because of its toxicity, high production volume,
and because it has been involved in a number of accidental releases
with reported migration of a vapor cloud off-site; some of these
incidents also resulted in worker deaths and injuries on-site. Several
commenters indicated that the accidents cited by EPA did not provide a
valid basis for listing for a number of reasons. First, some of the
accidents, according to commenters, actually involved fuming sulfuric
acid (oleum), which is a mixture of sulfuric acid and sulfur trioxide,
and vapor clouds reported from these accidents were attributable to
sulfur trioxide rather than sulfuric acid. Second, commenters stated
that the injuries in some accidents were caused by direct contact with
sulfuric acid rather than inhalation of vapor. Third, according to some
commenters, some accidents involved reactions of sulfuric acid with
other substances. Finally, comments were received which indicated there
have been no accidents involving vapor clouds of sulfuric acid that
caused off-site deaths or injuries, and that, in fact, the low vapor
pressure of sulfuric acid makes it impossible for an accidental release
to have any effect beyond the fenceline.
EPA is well aware that sulfuric acid has a low vapor pressure and
is unlikely to be released into the air under ambient conditions.
However, as noted above, EPA also believes that, exclusive of vapor
pressure, accident history can provide a valid basis, in combination
with toxicity and/or physical/chemical properties, for adding a
substance to the list. The Agency also notes that nothing in the
statute limits EPA to consider solely the effects of vapor inhalation
as a consequence of a release. As noted above, the EHS toxicity
criteria endorsed by the Senate are not limited to inhalation.
Furthermore, death, injuries, and environmental impacts caused by
direct contact are relevant to the risks posed by a chemical.
While believing the EPA has the authority to list sulfuric acid if
its accident history, in conjunction with its toxicity and significant
production volume, warrants listing, the comments received by the
Agency have created doubt about the accuracy of what has been reported
as air releases of sulfuric acid. For purposes of today's rulemaking,
the Agency has been unable to determine from accident history whether
sulfuric acid has generated an air release that has caused impact off-
site. Because of the uncertainty associated with past reported
accidental release information and the common confusion between oleum
and sulfuric acid in such reporting, the Agency has decided not to list
sulfuric acid at this time. Although sulfuric acid is not specifically
listed, facilities handling sulfuric acid are still subject to general
duty requirements. The Agency will continue to monitor and review
sulfuric acid accident reports to determine the need for listing at a
future time. EPA also seeks data on the off-site impacts of sulfuric
acid that could be used to evaluate whether sulfuric acid should be
added to the list.
Related to the sulfuric acid issue are comments suggesting that the
Agency specifically list oleum (fuming sulfuric acid), CAS number 8014-
95-7. Oleum is a mixture of sulfuric acid and sulfur trioxide. In the
proposed rule, the Agency believed oleum would be subject to section
112(r) requirements because both of its components, sulfuric acid and
sulfur trioxide, were proposed for listing, and because of the Agency's
proposed de-minimis concentration for mixtures. However, two commenters
noted that it is ``reasonable to include oleum as a regulated
chemical'' and that ``oleum and sulfuric acid must be listed
separately, since the fuming effects of an oleum release make it
potentially much more serious.'' The Agency agrees with commenters that
oleum should be included in this listing because of its accident
history, toxicity, and production volume. Furthermore, the Agency has
reviewed the accident history data relevant to oleum and sulfuric acid
and agrees with commenters that some of the accidents the Agency had
relied on to list sulfuric acid in fact involved oleum. Furthermore,
because of the revisions on the de-minimis concentration provisions and
the Agency's decision not to finalize the listing of sulfuric acid at
this time, oleum would no longer be subject to 112(r) provisions
without a specific listing. In order to continue the coverage of oleum
in the accidental release prevention provisions, EPA is specifically
listing all forms of oleum in the section 112(r) list of substances.
Phenol (in liquid form only), parathion, and nitrobenzene are also
included on the proposed list based on accident history. Several
commenters objected to the inclusion of these chemicals, for reasons
similar to those concerning the listing of sulfuric acid, i.e., the low
vapor pressure of these substances and the lack of sufficient
supporting accident history to provide a basis for listing. The Agency
generally agrees with the comments regarding these three specific
substances. Having considered the comments and having conducted further
review of accident history for these chemicals, the record indicates
that there are not a clearly significant number of accident reports
with effects, or potential effects, beyond the fenceline to merit
listing at this time.
Several commenters objected to the listing of other specific
substances for a variety of reasons, including low vapor pressure, low
toxicity, existing safety regulations, and accident history. The
chemicals mentioned include hydrogen peroxide, acrylonitrile, and
hydrochloric acid, among others. EPA has reviewed the comments on these
chemicals and categories of chemicals that were recommended for
deletion and has decided to, except as noted, retain them on the list
of regulated substances under section 112(r). As noted above, EPA is
revising the vapor pressure criterion and not proceeding to list 18
chemicals with vapor pressures below 10 mm Hg. In addition, the Agency
has determined that section 112(r)(3) prohibits it from listing methyl
bromide because the substance has been listed by regulation as an ozone
depleting chemical under CAA Title VI (see 58 FR 65018, December 10,
1993).
The Agency disagrees with commenters that seek deleting substances
because of other existing regulations. The listing of substances and
thresholds, as mandated by Congress, reflects the potential for these
listed substances to cause serious adverse effects to human health or
the environment. The Agency believes that considerations of other
regulations applicable to these regulated substances are appropriately
accounted for in accident prevention requirements developed for
facilities handling the regulated substances above the threshold
quantities, rather than in determining whether any listed substance
poses a potential hazard.
Several commenters recommended the deletion of substances that were
mandated for listing by Congress, including ammonia, toluene
diisocyanate, and anhydrous sulfur dioxide. The Agency believes that
the language of section 112(r)(3) precludes it from omitting these
chemicals from the initial list. The Agency will consider petitions to
delist these chemicals if such petitions comply with the petition
criteria announced today.
Several commenters recommended adding other specific substances,
such as chlordane and tetraethyl lead, to the list of regulated
substances. The Agency will consider these at the time it revises the
list promulgated today, or through the petition process. However, the
Agency notes that notwithstanding today's listing, these substances are
still subject to the general duty provisions, particularly if they are
in commercial production and use.
In the list rule proposal, EPA requested information to determine
the need and appropriateness of including radionuclides under this
rulemaking. Some commenters objected to including radionuclides while
others recommended inclusion. Still other commenters recommended the
inclusion of only some radionuclides. However, none of the commenters
provided sufficient technical information to assist the Agency in
determining whether or not radionuclides should be listed. Due to the
uncertainty associated with gaps in EPA's data and the appropriate
criteria for listing, the Agency has decided not to include
radionuclides in the initial list of regulated substances.
c. Other list options considered. EPA considered the option of
adopting the entire list of 360 toxic chemicals regulated under EPCRA
(SARA Title III) section 302. A small number of commenters favored this
option, believing that consistency with EPCRA is desirable, that having
a single list would help avoid confusion, and that listing additional
toxic substances would be more protective of the public. EPA did not
propose to adopt the entire EHS list because it includes a number of
solids and non-volatile liquids for which an effect beyond the
fenceline in the event of an accidental release is expected to be less
likely than for gaseous or volatile liquids. It also includes
substances that are not currently in commercial production. Congress
did not direct EPA to list all EHS substances. Instead, Congress
provided that the Administrator could include as few as 100 substances
on the initial list under section 112(r). In directing the
Administrator to ``use'' the EHS list, but not to be ``limited to''
this list, and in providing that ``such modifications as * * *
appropriate'' be made, the CAA provides the Agency with the flexibility
to cull from the EHS list and other sources a more focused list of
substances for accidental release prevention regulations. Most
commenters supported EPA's decision to propose for listing only those
EHSs that best reflect the statutory criteria of likelihood and
magnitude of release. For these reasons, EPA is not adopting the entire
EHS list.
d. Threshold quantities. EPA's proposed thresholds were lower than
OSHA's for 15 of the substances listed by both OSHA and EPA. A number
of commenters stated that EPA's thresholds should not be lower than
OSHA's for any listed substances, since in general, workers face a more
immediate threat of exposure in an accidental release than would the
public. Several commenters indicated that EPA should adopt the OSHA
thresholds for chemicals which EPA had assigned lower thresholds.
Conversely, there were other comments supporting the lower thresholds
proposed by EPA for several chemicals, based on the commenters'
experience with these chemicals.
EPA has reviewed the threshold quantities for the listed substances
and the OSHA thresholds for the substances on both the EPA and OSHA
lists prior to and after the proposal of EPA's rule. EPA recognizes the
practical importance of consistency with the OSHA list to the extent
possible, but also believes it is necessary to have a sound methodology
for assignment of threshold quantities; the CAA requires the Agency to
include an explanation of the basis for establishing the list, and to
account for specified factors in setting threshold quantities. OSHA's
thresholds were not required to reflect the factors EPA must consider.
The statute also provides for petitions to add new chemicals, and
requires the development of thresholds for such chemicals when listed.
A sound methodology is essential for making changes to the list and
thresholds after promulgation. The methodology adopted today considers
the factors required by the CAA under section 112(r)(5). No other
methodology was identified that EPA could use to derive thresholds that
would be consistent and equally applicable to the current listed
substances and to those that may be added in the future. Therefore, EPA
is not adopting the OSHA thresholds.
Nevertheless, EPA agrees with commenters that EPA should review its
proposed threshold methodology and quantity categories to ensure that
they accurately reflect the range of risks posed by the listed toxic
substances. Based on this review, EPA has decided to retain its
threshold methodology but revise the range of threshold quantities for
toxics. The minimum quantity remains at 500 pounds, representative of
drum-size containers, but the maximum threshold quantity is raised to
20,000 pounds, replacing the proposed 10,000 pound maximum. This higher
upper limit expands the range of threshold quantities to better reflect
the relative hazards among the listed toxics; the upper limit of 20,000
represents typical handling quantities, and would still be protective
of the public for those substances which now have the higher
thresholds. Threshold quantity categories for toxic substances are now:
500 pounds, 1,000 pounds, 2,500 pounds, 5,000 pounds, 10,000 pounds,
15,000 pounds, and 20,000 pounds.
Using this revised range, higher thresholds have been assigned for
most of the toxic substances listed based on the revised vapor pressure
criterion. Several toxic substances also meet the flammability
criteria, and thus could be assigned two thresholds. Toxic substances
that also meet the criteria for listing as flammable substances are
assigned the lower of the thresholds. Under the revised methodology,
the only substance that has a threshold quantity that is lower under
EPA than OSHA's PSM standard is methyl chloride, which meets the
criteria for listing for flammability and, therefore, is assigned a
threshold quantity of 10,000 pounds, rather than the 20,000 pounds that
would apply under the methodology for toxics. The OSHA threshold for
methyl chloride is 15,000 pounds. This is to account for those hazards
presented by the substance that are considered in this rulemaking; the
lowest threshold quantity is assigned to be more protective.
A number of commenters suggested that site-specific factors should
be considered in setting or modifying thresholds, such as population
density, ecosystem sensitivity, safety devices, experience, uses of the
substance, and handling conditions. EPA recognizes that these and many
other site-specific factors could affect the likelihood of occurrence
or the effects of a release. Accounting for these factors has the
advantage of more specifically tailoring threshold quantities based on
common use patterns of the substances and on the particular site in
which they would be used. One serious disadvantage of applying site-
specific factors to setting thresholds would be that such an approach
would be inappropriate for ubiquitous chemicals, such as chlorine and
ammonia, because of the innumerable applications that would have to be
considered. A greater disadvantage to this approach is that the
intrinsic hazard of a chemical will still be present even when it is
used outside of a ``typical'' scenario. As stated in the proposed rule,
EPA believes it is not feasible to develop a methodology for
establishing threshold quantities based on site-specific factors that
would be applicable uniformly nationwide. Therefore, EPA did not
incorporate site-specific factors in setting or modifying thresholds.
As discussed in the preamble section IV.B. Threshold Determination,
substance-specific factors and use scenarios are considered in
determining whether there is a threshold quantity on-site. Also, site
specific factors will more appropriately be accounted for in the
accidental release prevention regulations under section 112(r)(7). This
Agency rationale is also applicable to similar comments for
establishing thresholds for flammable and explosive substances.
e. Other threshold quantity options considered. In addition to the
proposed methodology for setting thresholds for toxic substances and
the use of OSHA thresholds as discussed above, EPA requested comment on
several other options. One option was use of the vapor quantity method,
based on air dispersion modeling, to determine the quantity in air
needed to equal the ``Immediately Dangerous to Life and Health'' (IDLH,
published by the National Institute for Occupational Safety and Health)
concentration level at 100 meters from the point of release. This
option was not generally supported by commenters. A second option was
to adopt the threshold planning quantities (TPQs) under EPCRA section
302. A small number of commenters favored this option, believing that
consistency with EPCRA would help to avoid confusion. EPA did not
propose this option because the TPQs are intended to represent a level
at which the chemical hazards should be considered by localities for
discretionary community planning purposes. As mentioned in the preamble
of the proposed rule, the thresholds established under this rule have a
different purpose, i.e., to indicate which facilities must comply with
mandatory facility-based prevention requirements. Any confusion that
results from two different threshold quantities applying to the same
chemical under two EPA emergency preparedness and prevention programs
is mitigated by the fact that the more onerous and detailed planning
requirements are triggered when greater, and presumably more dangerous,
quantities are present.
The third threshold option considered for toxics was adoption of
the OSHA thresholds for all substances listed by both EPA and OSHA. A
number of commenters favored this option. As noted above, EPA
recognizes the importance of consistency with OSHA. However, because of
EPA's statutory obligation to establish a methodology based on
specified factors, the Agency has elected not to adopt the OSHA
thresholds. The thresholds adopted in today's rule for chemicals listed
by EPA are, with the exception of methyl chloride, equal to or higher
than OSHA's.
2. Flammable Substances
EPA's listing of flammable gases and volatile flammable liquids was
generally supported by commenters, although a few commenters maintained
that, because OSHA regulates flammable substances, EPA should not list
them. The Agency disagrees that flammable substances should not be
listed for accident prevention and potential effects off-site, since
such substances pose a potential off-site hazard (namely, a vapor cloud
explosion) because of their inherent properties. The proposed threshold
for flammables, 10,000 pounds, was generally supported as well. EPA is
finalizing the proposed listing for flammables and their threshold
quantities.
Commenters also focused on specific flammable substances, including
methane, ethane, propane, and butane (some components of natural gas).
Commenters argued that special factors (e.g., the low density of
methane gas) justify not listing or modifying the listing of these
substances. EPA has reviewed the comments on specific flammable
substances and disagrees with the commenters. EPA believes there is
sufficient information, from both accident reports and modeling
results, to support the conclusion that flammable substances that meet
the listing criteria, in quantities above the threshold quantity of
10,000 pounds, could present a hazard to the public from a vapor cloud
explosion. EPA recognizes that, as noted by commenters, some situations
in which these substances are handled may present a lesser hazard than
others. However, these substances still pose a potential threat beyond
the fenceline in case of an accidental release. Therefore, in order to
be protective of the public, EPA is maintaining the same application of
the criteria for flammable substances as proposed for all listed
flammable substances. EPA's listing decision is based on the
substances' demonstrated or potential effects in the event of an
accidental release, not on existing regulations, standards, or
recommended practices applicable to the listed substances; these
factors may more appropriately be accounted for when accident
prevention regulations are promulgated under section 112(r)(7).
Several commenters recommended that EPA provide an exemption,
similar to the exemption under OSHA's PSM Standard, for flammable
liquids kept in atmospheric tanks below their normal boiling points.
Unlike OSHA, EPA is listing only flammable gases and volatile flammable
liquids. EPA considers these substances to be intrinsically hazardous,
regardless of conditions of storage, and, therefore, does not believe
it is appropriate to provide an exemption for atmospheric storage.
3. Explosives
Explosives classified by DOT as Class 1, Division 1.1 and listed as
such in 49 CFR 172.101 (the Hazardous Materials Table) are covered by
this rule with a threshold of 5,000 pounds. In 49 CFR 173.50, DOT
defines the term ``explosive'' as any substance or article, including a
device, which is designed to function by explosion (i.e., an extremely
rapid release of gas and heat) or which, by chemical reaction within
itself, is able to function in a similar manner even if not designed to
function by explosion, unless the substance or article is otherwise
classed under DOT provisions. Division 1.1 consists of explosives with
a mass explosion hazard; a mass explosion is one which affects almost
the entire load instantaneously. The Agency proposed to list all
substances that met the definition of Division 1.1 (58 FR 5110). The
Agency is clarifying and modifying its listing of explosive substances
to include only those substances listed in 49 CFR 172.101 (DOT's
Hazardous Material Table), which is a subset of all substances and
mixtures of substances that would meet DOT's Division 1.1 definition.
EPA noted in the preamble to the proposed rule that it believed
this threshold would apply primarily to manufacturers of high
explosives (58 FR 5112). More than 100 commenters, primarily explosives
distributors and users, objected to the listing of explosives in
general. These commenters maintained that explosives are regulated
adequately by a number of agencies, including the Bureau of Alcohol,
Tobacco, and Firearms (BATF), DOT, OSHA, the Mine Safety and Health
Administration (MSHA), and the Department of Defense (DOD). The
commenters believe the requirements of the existing regulations serve
to prevent accidents and cited the safety record of the explosives
industry as evidence. The commenters believe the American Table of
Distances, used by BATF to set distances for storage of explosives,
provides protection for the community from the effects of an accidental
explosion; this table is based on a lower overpressure level than the
3.0 psi used by EPA to set the threshold for explosives and, therefore,
is more protective of the public. In addition, a number of commenters
said the 5,000-pound threshold proposed by EPA would not restrict the
effects of the rule to manufacturers, as suggested by EPA, but would
also cover many distribution and use sites. They noted that, for
example, blasting may require only a small quantity of high explosive
(Division 1.1), but that the entire quantity of explosives on-site used
in blasting is treated as a high explosive; the high explosive portion
serves to initiate the reaction involving the entire quantity.
EPA acknowledged in the proposed rule that explosives are already
regulated by a number of agencies. However, these existing regulations
do not negate the properties of these substances. The explosives listed
in today's rule meet the criteria of section 112(r) (3) and (4) because
the inherent properties of the listed explosives plainly indicate that
such chemicals may have a severe impact in the event of a detonation.
The listed explosives represent the category of explosives that may
most easily detonate. In the event of an accidental detonation these
substances pose an inherent risk of off-site effects. Industry
requirements under other applicable regulations, or recommended
standards, are more appropriately accounted for in the development of
accidental release prevention requirements. The requirements for
accident prevention in section 112(r)(7) specifically allow for
recognition of industry-specific circumstances, including voluntary
prevention measures, in EPA's prevention regulations. No similar
provision is set forth in sections 112(r) (3), (4), or (5), which
covers the development of this list of substances and thresholds
quantities. Section 112(r)(7) implementing rules, as appropriate, will
allow for industry specific circumstances to be considered. Other
regulatory requirements, and other practices already in place aimed
specifically at protecting the public from adverse effects in case of
accidental releases are expected to be integrated with accident
prevention requirements of rulemaking under section 112(r)(7).
In particular, EPA's review of existing regulations indicates that
public safety would be enhanced if additional information about
explosives, such as hazards assessments, were available to emergency
response agencies and local emergency planners. Public safety would
also be enhanced if there were additional coordination between
facilities handling explosives and the local emergency planners and
responders. The listing of explosives will make information available
under section 112(r) rulemaking and facilitate this coordination.
Furthermore, current regulations do not provide for public
communication of potential off-site hazards, as do CAA Amendments
requirements under section 112(r)(7). Currently, only information
related to the quantity and location of explosives is available to the
public under sections 311 and 312 of EPCRA. Under the risk management
provisions of the CAA, the public will also have available to them
information about the measures being taken by the facility to prevent
off-site consequences from accidental detonations.
The Agency has noted that the practice of treating the entire
quantity of mixtures of high explosives with other explosives as high
explosives, coupled with the Agency's proposed threshold determination
rule for mixtures, creates the potential for coverage of explosive
formulations that are intended to be released (exploded) on-site. The
Agency did not intend such coverage in its proposal. In response to
this problem identified by the commenters, the Agency is modifying the
listing of explosives in today's final rule so that specific explosives
on the Hazardous Materials Table are identified as the regulated
substances. This avoids the potential circularity in the proposed
definition. Mixtures with substances listed on the Hazardous Materials
Table are potentially covered only through the operation of the
explosive mixture provision in the threshold determination portion of
today's rule. The Agency is also clarifying the coverage of explosive
mixtures to be used for intentional on-site detonations (not an
accidental release) when determining if a threshold quantity is present
in a process. This clarification is discussed later in today's
preamble.
B. Threshold Determination
Section 68.115 was originally proposed as section 68.5. It has been
consolidated with other subpart C provisions that relate to covered
substances and applicable thresholds. This section of the regulation
establishes how to estimate the presence of a threshold quantity.
Exemptions of those quantities that need not be accounted for in
determining a threshold are also included.
1. Basis for Threshold Determination
Comments on the proposed rule generally supported a threshold
quantity determination that is based on the quantity of a regulated
substance in a process. Some commenters, however, suggested that
determining threshold quantities should be based on the quantity on-
site, the average annual usage, or on-site specific factors. EPA
generally disagrees with these statements. The total quantity on-site,
while consistent with other regulations in determining threshold
quantities (particularly EPCRA, section 302) does not necessarily
represent the quantity that could be involved in an accident. The total
quantity on-site may include quantities in separate processes,
buildings, and locations within the same facility. The average annual
usage measures the quantity used by a facility in a year and is not
related to the maximum quantity that could be released at a given time.
Site-specific factors are appropriately accounted for both in defining
the process for which a threshold calculation must be undertaken and in
assessing the hazards and preparing the risk management plan for the
particular facility. As recommended by most commenters, EPA is
retaining the threshold determination based on the total quantity in a
process, using the same process definition as OSHA. This approach
focuses on the quantity of a substance that might be released in a
single accident, and that could be reasonably anticipated to cause
effects of concern as a result of an accidental release. This threshold
determination approach is consistent with OSHA's PSM standard.
2. Mixture Exemption
a. Toxic substances. The proposed rule included a de-minimis
concentration of one percent by weight for all listed substances
present in a mixture; i.e., quantities of a regulated substance in a
mixture did not have to be accounted for purposes of the threshold
quantity if the substance were present at concentrations below one
percent by weight. A number of comments were received on this exemption
for solutions and mixtures.
Several commenters suggested providing a threshold determination
method for mixtures based on the SHI. The partial pressure of the
listed substance in solution and its toxicity would be used to
determine the value of the SHI for the solution; the index value would
be compared to a cut-off value (commenters recommended a cut-off of
1,000). EPA does not agree that the SHI criteria should be used to
determine the mixture cut-off. Because the SHI approach was not used in
determining which chemicals to list, a mixtures score based on this
index would not relate to whether a chemical met the listing criteria.
EPA also remains concerned about the lack of a basis for the
recommended 1,000 SHI cut-off. In addition, EPA believes the SHI
approach would be difficult to implement within the structure of
section 112(r), especially for facilities outside the chemical
manufacturing industry.
Most of the commenters believed the one percent concentration cut-
off is too low for solutions of toxic substances; their position being
that one percent mixtures of a regulated substance pose essentially no
threat to the public. Several commenters also suggested that EPA should
provide specific concentration cut-offs for solutions of certain listed
substances, such as hydrogen fluoride, nitric acid, and sulfuric acid.
Several commenters suggested that the concentration cut-offs should be
raised for hydrochloric acid (listed for concentrations of 25 percent
or greater) and ammonia (listed for concentrations of 20 percent or
greater).
The Agency agrees with commenters that the one percent cut-off may
prove to be too conservative in certain circumstances, and that it may
not adequately reflect the decreased potential for air release of most
regulated substances in dilute mixtures or solutions; at very low
concentrations some of these mixtures or solutions fail to meet the
listing criteria. The Agency also believes, however, that no
justification would exist to exclude the quantities in mixtures or
solutions from the threshold calculation if it is uncertain that these
mixtures or solutions fail to meet the original listing criteria.
In response to these comments, EPA has modified the one percent
mixture exemption to reflect the amount of the regulated substance that
may reasonably be anticipated to cause an effect of concern in an
accidental release. The Agency has reassessed the concentration at
which certain dilute solutions of regulated substances may pose a
hazard to the community, sufficient to warrant treatment as a regulated
substance, for purposes of determining whether a threshold quantity is
present in a process. As part of this modification, EPA has decided to
provide specific cut-off concentrations for certain chemicals. These
chemicals, in mixtures or solutions with concentrations below the
specified cut-off, will not have to be considered in determining
whether a threshold quantity is present. For other chemicals, a method,
rather than a specific cut-off, will be provided to determine whether
mixtures should be considered in the threshold determination. The
following chemicals are now listed with concentration cut-offs (in
addition to those already proposed with concentrations cut-offs) as
shown for weight percent of the substances in water solution:
Hydrogen fluoride/Hydrofluoric acid (concentration 50
percent or greater); the listing of hydrogen fluoride has been
clarified to reflect that it includes the aqueous form of hydrogen
fluoride, hydrofluoric acid.
Nitric acid (concentration 80 percent or greater).
The concentration limits for hydrofluoric and nitric acid are based
on the partial pressures of these substances in water solution. At the
concentrations listed, the partial pressures of the solutions would
meet the vapor pressure criterion of 10 mm Hg. Also, EPA is raising the
proposed concentration cut-off for hydrochloric acid from 25 to 30
percent, based on water solutions, to meet the revised vapor pressure
criterion. EPA is not changing the concentration cut-off for ammonia
because the partial pressure of ammonia in a 20-percent solution still
exceeds the 10 mm Hg vapor pressure criterion.
Other listed toxic substances in solutions or mixtures must be
included in threshold determination if the partial pressure of the
substance in the solution or mixture is equal to, or exceeds, 10 mm Hg.
If the partial pressure of the regulated toxic substance in the mixture
is determined to be below 10 mm Hg under all conditions in process
handling or process storage, the solution or mixture need not be
considered in the threshold determination. If the partial pressure of
the regulated toxic substance in the mixture equals or exceeds 10 mm Hg
in portions of the process, then the quantity of the listed substance
contained in the mixture at these portions of the process shall be
included in determining whether a threshold is met. The facility will
be required to use the one percent de-minimis concentration in
determining threshold quantities unless it can measure or estimate, and
document, that the partial pressure of the regulated substance in the
mixture or solution is less than 10 mm Hg.
The methodology for determining the amount of a regulated substance
in a mixture to apply to thresholds does not apply to oleum, toluene
2,4-diisocyanate, toluene 2,6-diisocyanate, and toluene diisocyanate
(unspecified isomer). These substances have vapor pressures less than
10 mm Hg.
b. Flammable substances. The proposed rule included the same de-
minimis concentration of one percent by weight for all listed
substances present in a mixture for flammable substances. A number of
commenters noted that mixtures of flammable substances in
concentrations above one percent may not be flammable. They suggested
that a listed flammable substance in a mixture should be included in
threshold determination only if the mixture meets the flammability
criteria for listing. Other commenters suggested that the entire
mixture containing a listed substance should be treated as a regulated
substance if the mixture meets the listing criteria for flammable
substances. EPA agrees that a mixture containing a listed flammable
substance should only be considered in a threshold determination if the
mixture itself meets the criteria for an NFPA flammability rating of 4,
i.e., flash point below 22.8 deg. C (73 deg. F) and boiling point below
37.8 deg. C (100 deg. F). Again, as for the toxics in mixtures or
solutions, a facility is required to use the one percent de-minimis
concentration for threshold quantity calculations unless it can measure
or estimate, and document, that the mixture or solution does not have a
flash point below 22.8 deg. C (73 deg. F) and a boiling point below
37.8 deg. C (100 deg. F).
The Agency agrees with commenters who suggested that a mixture
containing a flammable regulated substance should be treated as the
regulated substance for purposes of determining whether a threshold
quantity is present if the mixture itself meets the boiling point and
flash point criteria of today's rule. EPA believes the hazards
associated with such highly flammable mixtures make it appropriate to
treat such mixtures as regulated substances when such mixtures meet the
flammability listing criteria. EPA recognizes that counting the entire
quantity of a flammable mixture for threshold determination differs
from the proposed rule and from the treatment of mixtures containing
regulated toxic substances. However, the Agency believes this different
treatment is appropriate because, for flammable substance mixtures, the
mixture is known to display the flammability hazard at levels that meet
the listing criteria, while for toxic substance mixtures, the mixture
is not known to meet the acute toxicity criterion. For toxic substance
mixtures, EPA requires counting towards a threshold only the portion of
the mixture that would meet the acute toxicity criterion (i.e., the
amount of the actual substance).
c. Explosive substances. A number of comments were received
regarding the threshold calculations for explosives, particularly for
mixtures of division 1.1 explosives with low explosives or blasting
agents at use sites. In the proposed rule, the Agency had established a
de-minimis concentration applicable to all listed substances.
Commenters pointed out problems with this mixture consideration, in
light of EPA's listing of all explosives meeting DOT's definition of
Division 1.1 hazardous materials. This definition treats the entire
quantity of a mixture containing a high explosive as a Division 1.1
explosive, hence negating the de-minimis calculation for purposes of
threshold quantity determinations. This affected particularly those
mixtures formulated on-site, prior to intentional detonations,
following BATF regulations. To minimize the potential for accidents,
these mixtures generally are made shortly before intentional on-site
explosions. The Agency recognizes that the intentional release (or
controlled release) in an explosion of mixtures containing a regulated
substance is not an accidental release. Thus, the Agency believes that
the amount of an explosive in such a mixture cannot be reasonably
anticipated to cause effects of concern as a result of an accidental
release when such quantities are intended to be released on-site.
Therefore, in addition to clarifying the listing of explosives only to
include those substances listed by DOT in 49 CFR 172.101, the Agency is
also clarifying the applicability of the mixture concentration
provision for explosives. For purposes of determining whether a
threshold quantity is present in a process involving explosives,
mixtures of Division 1.1 explosives listed by DOT in 49 CFR 172.101
(Hazardous Material Table) and other explosives need not to be included
when the mixture is intended to be used in an on-site non-accidental
release in a manner consistent with applicable BATF regulations.
Quantities of explosive regulated substances in mixtures that are not
intended to be used on-site in an intentional explosion would not be
exempt if such mixture would be treated as a Division 1.1 explosive
under 49 CFR parts 172 and 173.
The following two examples demonstrate how this threshold
determination provision would operate. An owner or operator of a
stationary source receives a mixture, or prepares a mixture, that
combines a small quantity of an explosive listed as Division 1.1
hazardous material in 49 CFR 172.101 with a large quantity of a
blasting agent, so that the total quantity is above the 5,000 lbs
threshold quantity established for listed explosives. If the owner or
operator intends to detonate the high explosive/blasting agent mixture
at the stationary source in a manner that is consistent with applicable
BATF regulations, then the owner or operator need not count the weight
of the mixture in determining whether the source has a threshold
quantity of the regulated substance on-site. If the owner or operator
intends to store, and then transport off-site the high explosive/
blasting agent mixture, and the entire mixture would be treated as
Division 1.1 explosive under applicable DOT regulations, then the
weight of the entire mixture would need to be calculated to determine
whether a threshold quantity is present.
3. Other Threshold Exemptions
Except as noted below, all other threshold exemptions in the
proposed rule are retained in the final rule. All comments received
concerning these exemptions favored the Agency's proposal. The Agency
continues to believe that the forms of regulated substances exempted in
today's rule cannot reasonably be anticipated to cause effects of
concern in the event of an accidental release.
Use for facility consumption as fuel: The Agency has deferred a
decision on the proposed exemption for listed flammable substances when
used solely for facility consumption as fuel. For a document relating
to this proposed exemption, see a supplemental notice published
elsewhere in this issue. The Agency intends to decide on whether to
promulgate this exemption on or before the date the final risk
management program rule is promulgated.
C. Petition Process
Section 68.120 of the rule establishes the specific administrative
and technical requirements for the submission of petitions to add or
delete substances from the list of regulated substances.
Several comments were received on the criteria for determining
whether a substance that is the subject of a petition should be listed
or delisted. Two commenters said the listing criteria are too narrow.
For example, it was argued that EPA should allow petitioners to develop
a case for listing toxic chemicals that do not meet the acute toxicity
criteria. Another commenter said the listing criteria are too broad,
and the standards for delisting are too stringent; delisting requires
demonstrating that the substance ``will not'' cause death, injury, or
environmental harm.
EPA believes the acute toxicity criteria for listing toxics, as
well as the volatility and accident history, provide a valid basis for
identification of chemicals that pose hazards to the community in case
of acute exposures resulting from an accidental release and is
retaining these criteria for petition review. The Agency is also
retaining the selection criteria for listing flammables and explosives.
EPA agrees that the petition requirements for delisting may be too
stringent and will delete substances from the list if it can be
determined that the substance, in case of an accidental release, ``is
not known or anticipated to'' cause death, injury, or serious adverse
effects to human health or the environment.
One commenter said the decision not to accept additional petitions
unless new data become available should be modified so that petitions
that present significant data not previously considered (whether or not
the data are new) can be accepted. The petition process provides that
when a petition is received, EPA will publish a notice in the Federal
Register requesting additional, pertinent scientific information that
was not identified by the petitioner. Interested parties will have the
opportunity to present significant data not included in the petition.
Therefore, EPA believes it is appropriate to accept additional
petitions on a substance only if new data become available.
Another commenter said the 18-month period proposed for review of
petitions should be shortened to six months. EPA believes the 18-month
review period is not excessive for carrying out a thorough review of
the petition and any public comments and publishing a decision
concerning the petition. Denials shall be published in the Federal
Register within 18 months of the Agency receiving the petition; for
petitions granted, the Agency will publish a proposed new listing
within 18 months.
D. Definitions
Section 68.3 of the regulation sets forth the definitions that will
apply to all regulations published under section 112(r). Some of the
terms used in other parts of the CAA are also applicable to section
112(r). In addition, a number of terms new to the CAA, resulting from
the implementation of section 112(r), are defined in section 68.3 for
purposes of all accidental release prevention regulations. These
definitions include terms necessary to communicate effectively the new
regulatory requirements.
Accidental Release: The definition proposed for accidental release
has been taken directly from the legislative language. Several
commenters, however, thought it appropriate that the Agency clarify
this definition to better focus on EPA's intent through this
regulation. Several commenters submitted that the definition of
accidental release should be clarified not to include routine emissions
to the environment. The Agency believes that the definition is clear in
specifying that and accidental release is an ``unanticipated emission''
of a regulated substance and that this would not include routine
emissions. Several commenters also had concerns regarding the inclusion
of the term ``other extremely hazardous substances'' in the definition
of accidental release. This term has also been taken directly from the
legislative language and the Agency believes it to be an important
component of this definition. Under section 112(r)(1) the owners and
operators of stationary sources have a duty to initiate specific
activities to prevent and mitigate accidental releases of any regulated
substance under 112(r)(3), or any other extremely hazardous substance.
Process: There were a number of comments related to EPA's
definition of process. The proposed definition was consistent with
OSHA's definition of process under their PSM standard, and included any
activity involving a regulated substance including any use, storage,
manufacturing, handling, or on-site movement of such substances, or
combination of these activities. Any group of vessels that is
interconnected, or separate vessels that are located such that a
regulated substance could be involved in a potential release, were
proposed to be considered a single process. Because of the need to
maintain as much consistency as possible with OSHA, EPA is retaining
this definition and is providing, in this preamble, some clarification
prompted by comments submitted on this issue.
Many commenters argued that the proposed definition included terms
that were not clear, such as interconnected vessels and single
processes. The commenters indicated, for example, that in some cases
vessels may be connected in indirect ways and still present a low
probability that they could be involved in a single release. The Agency
believes that this was already accounted for through the proposed
definition of process. To serve as clarification, interconnected
vessels that could be involved in a single release would include
vessels physically connected so that an event could lead to an
accidental release involving all these vessels at one time. The Agency
still believes that the facility is responsible in accounting for any
quantity of a regulated substance that could potentially be released
from one or more vessels, whether these are connected or not.
Stationary source: Several commenters requested clarification
regarding pipelines and whether listed flammable substances in pipeline
transfer stations would be covered by the rule under the stationary
source definition. Other commenters had questions regarding the
inclusion in this definition of transportation containers not under
active shipping orders. The Agency is clarifying the definition of
stationary source. For purposes of regulations under section 112(r),
the term stationary source does not apply to transportation conditions,
which would include storage incident to such transportation, of any
112(r) regulated substance. Pipelines, transfer stations, and other
activities already covered under DOT as transportation of hazardous
substances by pipeline, or incident to such transportation, under 49
CFR parts 192, 193 and 195 would not be covered. Transportation
containers that are not under active shipping papers are not considered
by EPA to be storage incident to transportation; the Agency considers
the definition of stationary source to include such containers.
E. Exemptions
The Agency is retaining the proposed exemption from this part for
ammonia used as an agricultural nutrient, when held by farmers. This
exemption was authorized by statute, and it was also generally
supported by commenters.
A number of commenters suggested that an exemption should be added
for natural gas, mainly because of other existing regulations. As
discussed previously in this preamble, EPA's listing of a substance is
based on the demonstrated or potential effects in the event of an
accidental release. Existing regulations may be targeted to reduce a
potential release, or the effects of a release, but do not negate the
hazards presented by the substances regulated. Existing requirements
under other regulations, standards, or recommended practices are to be
accounted for though the requirements of the risk management program
and any other prevention regulations under section 112(r).
F. Scope
An issue of concern to a number of commenters were the general duty
requirements under section 112(r)(1). Generally, commenters voiced some
confusion regarding what the requirements would be, and particularly
about which substances would be included. Because of similarities with
OSHA's general duty clause, commenters expressed the need for EPA to
develop guidance along the OSHA Field Operations Manual to assist
facilities in evaluating their compliance with these requirements.
The CAA identified the following activities as part of the general
duty requirements: Identification of hazards which may result from an
accidental release using appropriate hazard assessment techniques,
designing and maintaining a safe facility taking such steps as
necessary to prevent accidental releases, and actions which minimize
the consequences of an accidental release once it has occurred. Section
112(r)(1) specifically indicates that the general duty provision
applies in the same manner and to the same extent as OSHA's general
duty clause under section 654, title 29 of the U.S. Code. The Agency is
investigating the relationship between requirements under section
112(r) and OSHA's general duty provisions.
Comments were also received on the separate issuance of the list
and thresholds rule and the risk management program rule. The comments
focused on the difficulties for the regulated community to evaluate and
comment on the full impact of the list and thresholds without specific
information on the accident prevention requirements. The Agency agrees
that the separation of these rules does not allow the regulated
community the optimum opportunity to comment on the proposed
regulation. While the Agency recognizes that the two rules comprise a
single program, the statute allows for proposal and promulgation of the
list and thresholds rule prior to the proposal and promulgation of the
section 112(r)(7) rule. Because EPA's duty to publish the list and
thresholds rule arose before the duty to publish the risk management
program rule, the Agency was obligated to publish the proposed list and
thresholds rule before the section 112(r)(7)(B) proposed rule was
publishable. The Agency has just published a proposed notice for the
prevention requirements applicable to facilities having the listed
substances above the threshold quantities (Risk Management Programs for
Chemical Accidental Release Prevention, 58 FR 54190, October 20, 1993).
The comment period for the risk management program rule will be open at
the time this rule is finalized. This will give commenters the
opportunity to comment on the risk management program with the
knowledge of what substances are covered.
V. Summary of Provisions of the Final Rule
EPA is adding part 68 to title 40 of the Code of Federal
Regulations, including the list of regulated substances and threshold
quantities, as well as the requirements for the petition process to add
regulated substances to the list or to delete regulated substances from
the list.
Section 68.1 establishes the scope of the Part 68 chemical accident
prevention provisions.
Section 68.3 establishes definitions applicable to all Part 68
regulations.
Section 68.100 establishes the purpose of the subpart as the
designation of regulated substances and their threshold quantities, and
establishment of the requirements for petitions to add substances or
delete substances from the list.
Section 68.115 (proposed Sec. 68.5) establishes the procedures to
determine whether a threshold quantity of a regulated substance is
present at a stationary source. Specific exemptions to the threshold
determination procedure are also included for mixture concentrations,
articles, and certain uses and activities.
The final rule includes several exemptions for mixtures that have
been revised from the proposed rule. These are:
(1) For toxic substances present in a mixture or solution at a
concentration of one percent or greater by weight, the facility has the
option of demonstrating that the partial pressure of the regulated
substance in the solution under any or all storage or handling
conditions is less than 10 mm Hg; in this case, the quantity of the
regulated substance in the mixture in the portion of the process with a
partial pressure of less than 10 mm Hg would be exempt from threshold
determination;
(2) Mixtures containing regulated flammable substances are exempt
from threshold determination if the facility demonstrates that the
mixture itself does not meet the criteria for flammability (flash point
below 73 deg.F (22.8 deg.C) and boiling point below 100 deg.F
(37.8 deg.C); and
(3) Mixtures of Division 1.1 explosives listed in 49 CFR 172.101
and other explosives need not be considered when determining whether a
threshold quantity is present, provided that the mixture is intended to
be intentionally released (i.e., a non-accidental release) in a manner
consistent with DOT and BATF regulations.
Section 68.120 specifies the requirements for petitions to the
Agency to add substances to the list, and to delete substances from the
list. Petition requirements have been modified slightly to read that a
substance may be deleted from the list if adequate data are available
to determine that the substance, in the case of an accidental release,
is ``unlikely to cause'' (rather than ``will not cause'') death,
injury, or serious adverse effects to human health or the environment.
Section 68.125 exempts ammonia used as an agricultural nutrient
when held by a farmer.
Section 68.130 establishes the list of regulated substances,
including a list of toxic substances, a list of flammable substances,
and a list criterion for commercial high explosives. This section also
establishes the threshold quantities for all listed substances.
The final rule includes several changes to the proposed list and
thresholds. Eighteen substances, with vapor pressures below 10 mm Hg,
have been deleted from the proposed list of toxic substances, and one
substance (vinyl chloride) has been moved from the list of toxic
substances to the list of flammable substances. One substance, methyl
bromide, has been deleted because it is listed under Title VI of the
CAA. Four substances on the proposed list, included partly because of
their accident history, have been deleted while another, oleum, has
been specifically listed. The final list contains 77 toxic substances.
Concentration cut-off levels have been specified for solutions of two
additional substances, hydrogen fluoride and nitric acid. The
concentration cut-off level has been raised for hydrochloric acid from
25 to 30 percent by weight. Threshold quantities have been raised for
71 of the 77 toxic substances listed. The final list contains 63
flammable substances, with the threshold quantity remaining at 10,000
lbs. The listing of explosive substances has been modified only to
include those substances listed by DOT in 49 CFR 172.101; the Agency is
also clarifying the applicability of the mixture concentration
provision for explosives.
VI. Required Analyses
A. E.O. 12866
Under Executive Order 12866, 58 Federal Register 51735 (October 4,
1993), the Agency must determine whether the regulatory action is
``significant'', and therefore subject to OMB review and the
requirements of the Executive Order. 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 or
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 government 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 entitlements, 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 Executive Order.
Pursuant to the terms of the Executive Order 12866, it has been
determined that this rule is a ``significant regulatory action''. Even
though the list and thresholds rule, by itself, imposes no cost on
facilities, the cost impact of the list and thresholds derives from
compliance with the risk management program regulations and other
reasonable regulations, which are triggered by the presence of a
regulated substance above its threshold quantity. The annual effect on
the economy for the accidental release prevention regulations that will
be triggered by this rule is expected to exceed $100 million. As such,
this action is submitted to OMB for review as part of a larger
accidental release prevention program. Changes made in response to OMB
suggestions or recommendations will be documented in the public record.
The Agency developed a draft Regulatory Impacts Analysis (RIA) for
the proposed rule that considered the cost for the accidental release
prevention program envisioned under section 112(r); this draft RIA
includes the list and thresholds and the risk management program
requirements. The list rule, by itself, imposes only very minimal costs
associated with the petition requirements for additions to, and
deletions from, the list and for the documentation of mixtures; the
majority of costs relate to actions that facilities with listed
chemicals must undertake as a result of the risk management program
rule.
The requirements under the OSHA Process Safety Management Standard,
which parallels the EPA risk management planning requirements, have now
been in place for some time, and information is becoming available on
the costs to facilities working to comply with OSHA. An addendum to the
draft RIA was developed for the proposed risk management program rule
to reflect public comments and the new information. The Agency estimate
of the universe of facilities covered by the final list and thresholds
rule has since been revised. EPA now estimates that approximately
118,000 facilities will be covered by the final list and thresholds
rule. The distribution of facilities covered includes 11,000
manufacturers and 107,000 non-manufacturers (i.e., refineries; public
drinking water and waste treatment systems; cold storage facilities;
wholesalers; agricultural retailers; service industry facilities;
private utilities; propane retailers, propane users, explosives
manufacturers, and gas extraction and processing facilities). The
average number of regulated substances per facility varies from one for
cold storage facilities to six for highly complex manufacturing
facilities.
EPA estimates that the petition process under this rulemaking will
cost a facility submitting a petition an average of $5,000. EPA
estimates that there will be 11 petitions a year. EPA anticipates that
the cost to the Federal government for processing and reviewing the
petitions will be approximately equal to the cost to facilities for
filing a petition. The total annual cost is estimated to be $110,000
($5,000x2x11 petitions).
B. Regulatory Flexibility Act
Pursuant to the Regulatory Flexibility Act of 1980, 5 U.S.C. 601 et
seq., when an agency publishes a notice of rulemaking, for a rule that
will have a significant effect on a substantial number of small
entities, the agency must prepare and make available for public comment
a regulatory flexibility analysis that considers the effect of the rule
on small entities (i.e., small businesses, small organizations, and
small governmental jurisdictions).
The list rule, by itself, imposes only very minimal costs
associated with the petition requirements for additions to, and
deletions from, the list and for the documentation of mixtures; the
majority of costs relate to actions that facilities with listed
chemicals must undertake as a result of the risk management program
rule. The risk management program regulation was proposed by EPA on
October 20, 1993 (58 FR 54190); a discussion of the impacts on small
entities is included on page 54212. The initial Regulatory Flexibility
Analysis is contained in the combined economic analysis entitled
Regulatory Impact Analysis in Support of Listing Regulated Substances
and Thresholds and Mandating Risk Management Programs for Chemical
Accident Prevention, as Required by Section 112(r) of the CAA,
available in the docket. A revised economic analysis will be developed
in conjunction with the final risk management program regulation.
C. Paperwork Reduction Act
The information collection requirements contained in this rule have
been approved by the Office of Management and Budget (OMB) under the
provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. and
have been assigned control number 2050-0127.
Public reporting for this collection of information in the petition
process is estimated to be approximately 138 hours per response,
including time for reviewing instructions, searching existing data
sources, gathering and maintaining the data needed, and completing and
reviewing the collection of information. EPA estimates that there will
be 11 petitions a year. The total annual burden is estimated to be
1,518 hours (138 hours x 11 petitions).
Send comments regarding the burden estimate or any other aspect of
this collection of information, including suggestions for reducing the
burden, to:
Chief, Information Policy Branch, PM-223, U.S., Environmental
Protection Agency, 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.''
D. Display of OMB Control Numbers
EPA is also amending the table of currently approved information
collection request (ICR) control numbers issued by OMB for various
regulations. This amendment updates the table to accurately display
those information requirements contained in this final rule. This
display of the OMB control number and its subsequent codification in
the Code of Federal Regulations satisfies the requirements of the
Paperwork Reduction Act (44 U.S.C. 3501 et seq.) and OMB's implementing
regulations at 5 CFR part 1320.
The ICR was previously subject to public notice and comment prior
to OMB approval. As a result, EPA finds that there is ``good cause''
under section 553(b)(B) of the Administrative Procedure Act (5 U.S.C.
553(b)(B)) to amend this table without prior notice and comment. Due to
the technical nature of the table, further notice and comment would be
unnecessary. For the same reasons, EPA also finds that there is good
cause under 5 U.S.C. 553(d)(3).
List of Subjects
40 CFR Part 9
Environmental protection, paperwork reduction act.
40 CFR Part 68
Environmental protection, Chemicals, Chemical accident prevention,
Clean Air Act, Extremely hazardous substances, Intergovernmental
relations, Hazardous substances, Reporting and Recordkeeping
requirements.
Dated: January 14, 1994.
Carol M. Browner,
Administrator.
For the reasons set out in the preamble, title 40, chapter I,
subchapter A, part 9 of the Code of Federal Regulations is amended, and
title 40, chapter I, subchapter C, part 68 of the Code of Federal
Regulations is added, as set forth below:
PART 9--OMB APPROVALS UNDER THE PAPERWORK REDUCTION ACT
1. The authority citation for part 9 continues to read as follows:
Authority: 7 U.S.C. 135 et seq., 136-136y; 15 U.S.C. 2001, 2003,
2005, 2006, 2601-2671; 21 U.S.C. 331j, 346a, 348; 31 U.S.C. 9701; 33
U.S.C. 1251 et seq., 1311, 1313d, 1314, 1321, 1326, 1330, 1344, 1345
(d) and (e), 1361; E.O. 11735, 38 FR 21243, 3 CFR, 1971-1975 Comp.
p. 973; 42 U.S.C. 241, 242b, 243, 246, 300f, 300g, 300g-1, 300g-2,
300g-3, 300g-4, 300g-5, 300g-6, 300j-1, 300j-2, 300j-3, 300j-4,
300j-9, 1857 et seq., 6901-6992k, 7401-7671q, 7542, 9601-9657,
11023, 11048.
2. Section 9.1 is amended by adding the new entry with a new
heading to the table to read as follows:
Sec. 9.1 OMB approvals under the Paperwork Reduction Act.
* * * * *
------------------------------------------------------------------------
OMB control
40 CFR citation No.
------------------------------------------------------------------------
*****
Chemical Accident Prevention Provisions:
68.120 (a), (e), and (g)................................. 2050-0127
*****
------------------------------------------------------------------------
3. Part 68 is added to read as follows:
PART 68--CHEMICAL ACCIDENT PREVENTION PROVISIONS
Subpart A--General
Sec.
68.1 Scope.
68.3 Definitions.
Subpart B--Risk Management Plan Requirements [Reserved]
Subpart C--Regulated Substances for Accidental Release Prevention
68.100 Purpose.
68.115 Threshold determination.
68.120 Petition process.
68.125 Exemptions.
68.130 List of substances.
Authority: 42 U.S.C. 7412(r), 7601.
Subpart A--General
Sec. 68.1 Scope.
This Part sets forth the list of regulated substances and
thresholds, the petition process for adding or deleting substances to
the list of regulated substances, the requirements for owners or
operators of stationary sources concerning the prevention of accidental
releases, and the State accidental release prevention programs approved
under section 112(r). The list of substances, threshold quantities, and
accident prevention regulations promulgated under this part do not
limit in any way the general duty provisions under section 112(r)(1).
Sec. 68.3 Definitions.
For the purposes of this Part:
Accidental release means an unanticipated emission of a regulated
substance or other extremely hazardous substance into the ambient air
from a stationary source.
Administrator means the administrator of the U.S. Environmental
Protection Agency.
Article means a manufactured item, as defined under 29 CFR
1910.1200(b), that is formed to a specific shape or design during
manufacture, that has end use functions dependent in whole or in part
upon the shape or design during end use, and that does not release or
otherwise result in exposure to a regulated substance under normal
conditions of processing and use.
CAS means the Chemical Abstracts Service.
DOT means the United States Department of Transportation.
Process means any activity involving a regulated substance
including any use, storage, manufacturing, handling, or on-site
movement of such substances, or combination of these activities. For
the purposes of this definition, any group of vessels that are
interconnected, or separate vessels that are located such that a
regulated substance could be involved in a potential release, shall be
considered a single process.
Regulated substance is any substance listed pursuant to section
112(r)(3) of the Clean Air Act as amended, in Sec. 68.130.
Stationary source means any buildings, structures, equipment,
installations, or substance emitting stationary activities which belong
to the same industrial group, which are located on one or more
contiguous properties, which are under the control of the same person
(or persons under common control), and from which an accidental release
may occur. A stationary source includes transportation containers that
are no longer under active shipping papers and transportation
containers that are connected to equipment at the stationary source for
the purposes of temporary storage, loading, or unloading. The term
stationary source does not apply to transportation, including the
storage incident to transportation, of any regulated substance or any
other extremely hazardous substance under the provisions of this part,
provided that such transportation is regulated under 49 CFR parts 192,
193, or 195. Properties shall not be considered contiguous solely
because of a railroad or gas pipeline right-of-way.
Threshold quantity means the quantity specified for regulated
substances pursuant to section 112(r)(5) of the Clean Air Act as
amended, listed in Sec. 68.130 and determined to be present at a
stationary source as specified in Sec. 68.115 of this Part.
Vessel means any reactor, tank, drum, barrel, cylinder, vat,
kettle, boiler, pipe, hose, or other container.
Subpart B--Risk Management Plan Requirements [Reserved]
Subpart C--Regulated Substances for Accidental Release Prevention
Sec. 68.100 Purpose.
This subpart designates substances to be listed under section
112(r)(3), (4), and (5) of the Clean Air Act, as amended, identifies
their threshold quantities, and establishes the requirements for
petitioning to add or delete substances from the list.
Sec. 68.115 Threshold determination.
(a) A threshold quantity of a regulated substance listed in
Sec. 68.130 is present at a stationary source if the total quantity of
the regulated substance contained in a process exceeds the threshold.
(b) For the purposes of determining whether more than a threshold
quantity of a regulated substance is present at the stationary source,
the following exemptions apply:
(1) Concentrations of a regulated toxic substance in a mixture. If
a regulated substance is present in a mixture and the concentration of
the substance is below one percent by weight of the mixture, the amount
of the substance in the mixture need not be considered when determining
whether more than a threshold quantity is present at the stationary
source. Except for oleum, toluene 2,4-diisocyanate, toluene 2,6-
diisocyanate, and toluene diisocyanate (unspecified isomer), if the
concentration of the regulated substance in the mixture is one percent
or greater by weight, but the owner or operator can demonstrate that
the partial pressure of the regulated substance in the mixture
(solution) under handling or storage conditions in any portion of the
process is less than 10 millimeters of mercury (mm Hg), the amount of
the substance in the mixture in that portion of the process need not be
considered when determining whether more than a threshold quantity is
present at the stationary source. The owner or operator shall document
this partial pressure measurement or estimate.
(2) Concentrations of a regulated flammable substance in a mixture.
If a regulated substance is present in a mixture and the concentration
of the substance is below one percent by weight of the mixture, the
mixture need not be considered when determining whether more than a
threshold quantity of the regulated substance is present at the
stationary source. If the concentration of the regulated substance in
the mixture is one percent or greater by weight, then, for purposes of
determining whether more than a threshold quantity is present at the
stationary source, the entire weight of the mixture shall be treated as
the regulated substance unless the owner or operator can demonstrate
that the mixture itself does not meet the criteria for flammability of
flash point below 73 deg.F (22.8 deg.C) and boiling point below
100 deg.F (37.8 deg.C). The owner or operator shall document these
flash point and boiling point measurements or estimates.
(3) Concentrations of a regulated explosive substance in a mixture.
Mixtures of Division 1.1 explosives listed in 49 CFR 172.101 (Hazardous
Materials Table) and other explosives need not be included when
determining whether a threshold quantity is present in a process, when
the mixture is intended to be used on-site in a non-accidental release
in a manner consistent with applicable BATF regulations. Other mixtures
of Division 1.1 explosives listed in 49 CFR 172.101 and other
explosives shall be included in determining whether more than a
threshold quantity is present in a process if such mixtures would be
treated as Division 1.1 explosives under 49 CFR Parts 172 and 173.
(4) Articles. Regulated substances contained in articles need not
be considered when determining whether more than a threshold quantity
is present at the stationary source.
(5) Uses. Regulated substances, when in use for the following
purposes, need not be included in determining whether more than a
threshold quantity is present at the stationary source:
(i) Use as a structural component of the stationary source;
(ii) Use of products for routine janitorial maintenance;
(iii) Use by employees of foods, drugs, cosmetics, or other
personal items containing the regulated substance; and
(iv) Use of regulated substances present in process water or non-
contact cooling water as drawn from the environment or municipal
sources, or use of regulated substances present in air used either as
compressed air or as part of combustion.
(6) Activities in Laboratories. If a regulated substance is
manufactured, processed, or used in a laboratory at a stationary source
under the supervision of a technically qualified individual as defined
in Sec. 720.3(ee) of this chapter, the quantity of the substance need
not be considered in determining whether a threshold quantity is
present. This exemption does not apply to:
(i) Specialty chemical production;
(ii) Manufacture, processing, or use of substances in pilot plant
scale operations; and
(iii) Activities conducted outside the laboratory.
Sec. 68.120 Petition process.
(a) Any person may petition the Administrator to modify, by
addition or deletion, the list of regulated substances identified in
Sec. 68.130. Based on the information presented by the petitioner, the
Administrator may grant or deny a petition.
(b) A substance may be added to the list if, in the case of an
accidental release, it is known to cause or may be reasonably
anticipated to cause death, injury, or serious adverse effects to human
health or the environment.
(c) A substance may be deleted from the list if adequate data on
the health and environmental effects of the substance are available to
determine that the substance, in the case of an accidental release, is
not known to cause and may not be reasonably anticipated to cause
death, injury, or serious adverse effects to human health or the
environment.
(d) No substance for which a national primary ambient air quality
standard has been established shall be added to the list. No substance
regulated under Title VI of the Clean Air Act, as amended, shall be
added to the list.
(e) The burden of proof is on the petitioner to demonstrate that
the criteria for addition and deletion are met. A petition will be
denied if this demonstration is not made.
(f) The Administrator will not accept additional petitions on the
same substance following publication of a final notice of the decision
to grant or deny a petition, unless new data becomes available that
could significantly affect the basis for the decision.
(g) Petitions to modify the list of regulated substances must
contain the following:
(1) Name and address of the petitioner and a brief description of
the organization(s) that the petitioner represents, if applicable;
(2) Name, address, and telephone number of a contact person for the
petition;
(3) Common chemical name(s), common synonym(s), Chemical Abstracts
Service number, and chemical formula and structure;
(4) Action requested (add or delete a substance);
(5) Rationale supporting the petitioner's position; that is, how
the substance meets the criteria for addition and deletion. A short
summary of the rationale must be submitted along with a more detailed
narrative; and
(6) Supporting data; that is, the petition must include sufficient
information to scientifically support the request to modify the list.
Such information shall include:
(i) A list of all support documents;
(ii) Documentation of literature searches conducted, including, but
not limited to, identification of the database(s) searched, the search
strategy, dates covered, and printed results;
(iii) Effects data (animal, human, and environmental test data)
indicating the potential for death, injury, or serious adverse human
and environmental impacts from acute exposure following an accidental
release; printed copies of the data sources, in English, should be
provided; and
(iv) Exposure data or previous accident history data, indicating
the potential for serious adverse human health or environmental effects
from an accidental release. These data may include, but are not limited
to, physical and chemical properties of the substance, such as vapor
pressure; modeling results, including data and assumptions used and
model documentation; and historical accident data, citing data sources.
(h) Within 18 months of receipt of a petition, the Administrator
shall publish in the Federal Register a notice either denying the
petition or granting the petition and proposing a listing.
Sec. 68.125 Exemptions.
Agricultural nutrients. Ammonia used as an agricultural nutrient,
when held by farmers, is exempt from all provisions of this part.
Sec. 68.130 List of substances.
(a) Explosives listed by DOT as Division 1.1 in 49 CFR 172.101 are
covered under section 112(r) of the Clean Air Act. The threshold
quantity for explosives is 5,000 pounds.
(b) Regulated toxic and flammable substances under section 112(r)
of the Clean Air Act are the substances listed in Tables 1, 2, 3, and
4. Threshold quantities for listed toxic and flammable substances are
specified in the tables.
(c) The basis for placing toxic and flammable substances on the
list of regulated substances are explained in the notes to the list.
Table 1 to Sec. 68.130.--List of Regulated Toxic Substances and
Threshold Quantities for Accidental Release Prevention
[Alphabetical Order--77 Substances]
------------------------------------------------------------------------
Threshold
Chemical name CAS No. quantity Basis for
(lbs) listing
------------------------------------------------------------------------
Acrolein [2-Propenal]............ 107-02-8 5,000 b
Acrylonitrile [2-Propenenitrile]. 107-13-1 20,000 b
Acrylyl chloride [2-Propenoyl 814-68-6 5,000 b
chloride].
Allyl alcohol [2-Propen-l-ol].... 107-18-61 15,000 b
Allylamine [2-Propen-l-amine].... 107-11-9 10,000 b
Ammonia (anhydrous).............. 7664-41-7 10,000 a, b
Ammonia (conc 20% or greater).... 7664-41-7 20,000 a, b
Arsenous trichloride............. 7784-34-1 15,000 b
Arsine........................... 7784-42-1 1,000 b
Boron trichloride [Borane, 10294-34-5 5,000 b
trichloro-].
Boron trifluoride [Borane, 7637-07-2 5,000 b
trifluoro-].
Boron trifluoride compound with 353-42-4 15,000 b
methyl ether (1:1) [Boron,
trifluoro[oxybis[metane]]-, T-4-.
Bromine.......................... 7726-95-6 10,000 a, b
Carbon disulfide................. 75-15-0 20,000 b
Chlorine......................... 7782-50-5 2,500 a, b
Chlorine dioxide [Chlorine oxide 10049-04-4 1,000 c
(ClO2)].
Chloroform [Methane, trichloro-]. 67-66-3 20,000 b
Chloromethyl ether [Methane, 542-88-1 1,000 b
oxybis[chloro-].
Chloromethyl methyl ether 107-30-2 5,000 b
[Methane, chloromethoxy-].
Crotonaldehyde [2-Butenal]....... 4170-30-3 20,000 b
Crotonaldehyde, (E)- [2-Butenal, 123-73-9 20,000 b
(E)-].
Cyanogen chloride................ 506-77-4 10,000 c
Cyclohexylamine [Cyclohexanamine] 108-91-8 15,000 b
Diborane......................... 19287-45-7 2,500 b
Dimethyldichlorosilane [Silane, 75-78-5 5,000 b
dichlorodimethyl-].
1,1-Dimethylhydrazine [Hydrazine, 57-14-7 15,000 b
1,1-dimethyl-].
Epichlorohydrin [Oxirane, 106-89-8 20,000 b
(chloromethyl)-].
Ethylenediamine [1,2- 107-15-3 20,000 b
Ethanediamine].
Ethyleneimine [Aziridine]........ 151-56-4 10,000 b
Ethylene oxide [Oxirane]......... 75-21-8 10,000 a, b
Fluorine......................... 7782-41-4 1,000 b
Formaldehyde (solution).......... 50-00-0 15,000 b
Furan............................ 110-00-9 5,000 b
Hydrazine........................ 302-01-2 15,000 b
Hydrochloric acid (conc 30% or 7647-01-0 15,000 d
greater).
Hydrocyanic acid................. 74-90-8 2,500 a, b
Hydrogen chloride (anhydrous) 7647-01-0 5,000 a
[Hydrochloric acid].
Hydrogen fluoride/Hydrofluoric 7664-39-3 1,000 a, b
acid (conc 50% or greater)
[Hydrofluoric acid].
Hydrogen selenide................ 7783-07-5 500 b
Hydrogen sulfide................. 7783-06-4 10,000 a, b
Iron, pentacarbonyl- [Iron 13463-40-6 2,500 b
carbonyl (Fe(CO)5), (TB-5-11)-].
Isobutyronitrile [Propanenitrile, 78-82-0 20,000 b
2-methyl-].
Isopropyl chloroformate 108-23-6 15,000 b
[Carbonochloridic acid, 1-
methylethyl ester].
Methacrylonitrile [2- 126-98-7 10,000 b
Propenenitrile, 2-methyl-].
Methyl chloride [Methane, chloro- 74-87-3 10,000 a
].
Methyl chloroformate 79-22-1 5,000 b
[Carbonochloridic acid,
methylester].
Methyl hydrazine [Hydrazine, 60-34-4 15,000 b
methyl-].
Methyl isocyanate [Methane, 624-83-9 10,000 a, b
isocyanato-].
Methyl mercaptan [Methanethiol].. 74-93-1 10,000 b
Methyl thiocyanate [Thiocyanic 556-64-9 20,000 b
acid, methyl ester].
Methyltrichlorosilane [Silane, 75-79-6 5,000 b
trichloromethyl-].
Nickel carbonyl.................. 13463-39-3 1,000 b
Nitric acid (conc 80% or greater) 7697-37-2 15,000 b
Nitric oxide [Nitrogen oxide 10102-43-9 10,000 b
(NO)].
Oleum (Fuming Sulfuric acid) 8014-95-7 10,000 e
[Sulfuric acid, mixture with
sulfur trioxide]\1\.
Peracetic acid [Ethaneperoxoic 79-21-0 10,000 b
acid].
Perchloromethylmercaptan 594-42-3 10,000 b
[Methanesulfenyl chloride,
trichloro-].
Phosgene [Carbonic dichloride]... 75-44-5 500 a, b
Phosphine........................ 7803-51-2 5,000 b
Phosphorus oxychloride 10025-87-3 5,000 b
[Phosphoryl chloride].
Phosphorus trichloride 7719-12-2 15,000 b
[Phosphorous trichloride].
Piperidine....................... 110-89-4 15,000 b
Propionitrile [Propanenitrile]... 107-12-0 10,000 b
Propyl chloroformate 109-61-5 15,000 b
[Carbonochloridic acid,
propylester].
Propyleneimine [Aziridine, 2- 75-55-8 10,000 b
methyl-].
Propylene oxide [Oxirane, methyl- 75-56-9 10,000 b
].
Sulfur dioxide (anhydrous)....... 7446-09-5 5,000 a, b
Sulfur tetrafluoride [Sulfur 7783-60-0 2,500 b
fluoride (SF4), (T-4)-].
Sulfur trioxide.................. 7446-11-9 10,000 a, b
Tetramethyllead [Plumbane, 75-74-1 10,000 b
tetramethyl-].
Tetranitromethane [Methane, 509-14-8 10,000 b
tetranitro-].
Titanium tetrachloride [Titanium 7550-45-0 2,500 b
chloride (TiCl4) (T-4)-].
Toluene 2,4-diisocyanate 584-84-9 10,000 a
[Benzene, 2,4-diisocyanato-1-
methyl-]\1\.
Toluene 2,6-diisocyanate 91-08-7 10,000 a
[Benzene, 1,3-diisocyanato-2-
methyl-]\1\.
Toluene diisocyanate (unspecified 26471-62-5 10,000 a
isomer) [Benzene, 1,3-
diisocyanatomethyl-]\1\.
Trimethylchlorosilane [Silane, 75-77-4 10,000 b
chlorotrimethyl-].
Vinyl acetate monomer [Acetic 108-05-4 15,000 b
acid ethenyl ester].
------------------------------------------------------------------------
\1\The mixture exemption in Sec. 68.115(b)(1) does not apply to the
substance.
Note: Basis for Listing:
aMandated for listing by Congress.
bOn EHS list, vapor pressure 10 mmHg or greater.
cToxic gas.
dToxicity of hydrogen chloride, potential to release hydrogen chloride,
and history of accidents.
eToxicity of sulfur trioxide and sulfuric acid, potential to release
sulfur trioxide, and history of accidents.
Table 2 to Sec. 68.130.--List of Regulated Toxic Substances and
Threshold Quantities for Accidental Release Prevention
[CAS Number Order--77 Substances]
------------------------------------------------------------------------
Threshold
CAS No. Chemical name quantity Basis for
(lbs) listing
------------------------------------------------------------------------
50-00-0............. Formaldehyde (solution).... 15,000 b
57-14-7............. 1,1-Dimethylhydrazine 15,000 b
[Hydrazine, 1,1-dimethyl-].
60-34-4............. Methyl hydrazine 15,000 b
[Hydrazine, methyl-].
67-66-3............. Chloroform [Methane, 20,000 b
trichloro-].
74-87-3............. Methyl chloride [Methane, 10,000 a
chloro-].
74-90-8............. Hydrocyanic acid........... 2,500 a, b
74-93-1............. Methyl mercaptan 10,000 b
[Methanethiol].
75-15-0............. Carbon disulfide........... 20,000 b
75-21-8............. Ethylene oxide [Oxirane]... 10,000 a, b
75-44-5............. Phosgene [Carbonic 500 a, b
dichloride].
75-55-8............. Propyleneimine [Aziridine, 10,000 b
2-methyl-].
75-56-9............. Propylene oxide [Oxirane, 10,000 b
methyl-].
75-74-1............. Tetramethyllead [Plumbane, 10,000 b
tetramethyl-].
75-77-4............. Trimethylchlorosilane 10,000 b
[Silane, chlorotrimethyl-].
75-78-5............. Dimethyldichlorosilane 5,000 b
[Silane, dichlorodimethyl-
].
75-79-6............. Methyltrichlorosilane 5,000 b
[Silane, trichloromethyl-].
78-82-0............. Isobutyronitrile 20,000 b
[Propanenitrile, 2-methyl-
].
79-21-0............. Peracetic acid 10,000 b
[Ethaneperoxoic acid].
79-22-1............. Methyl chloroformate 5,000 b
[Carbonochloridic acid,
methylester].
91-08-7............. Toluene 2,6-diisocyanate 10,000 a
[Benzene, 1,3-diisocyanato-
2-methyl-]\1\.
106-89-8............ Epichlorohydrin [Oxirane, 20,000 b
(chloromethyl)-].
107-02-8............ Acrolein [2-Propenal]...... 5,000 b
107-11-9............ Allylamine [2-Propen-1- 10,000 b
amine].
107-12-0............ Propionitrile 10,000 b
[Propanenitrile].
107-13-1............ Acrylonitrile [2- 20,000 b
Propenenitrile].
107-15-3............ Ethylenediamine [1,2- 20,000 b
Ethanediamine].
107-18-6............ Allyl alcohol [2-Propen-1- 15,000 b
ol].
107-30-2............ Chloromethyl methyl ether 5,000 b
[Methane, chloromethoxy-].
108-05-4............ Vinyl acetate monomer 15,000 b
[Acetic acid ethenyl
ester].
108-23-6............ Isopropyl chloroformate 15,000 b
[Carbonochloridic acid, 1-
methylethyl ester].
108-91-8............ Cyclohexylamine 15,000 b
[Cyclohexanamine].
109-61-5............ Propyl chloroformate 15,000 b
[Carbonochloridic acid,
propylester].
110-00-9............ Furan...................... 5,000 b
110-89-4............ Piperidine................. 15,000 b
123-73-9............ Crotonaldehyde, (E)- [2- 20,000 b
Butenal, (E)-].
126-98-7............ Methacrylonitrile [2- 10,000 b
Propenenitrile, 2-methyl-].
151-56-4............ Ethyleneimine [Aziridine].. 10,000 b
302-01-2............ Hydrazine.................. 15,000 b
353-42-4............ Boron trifluoride compound 15,000 b
with methyl ether (1:1)
[Boron,
trifluoro[oxybis[methane]]-
, T-4-.
506-77-4............ Cyanogen chloride.......... 10,000 c
509-14-8............ Tetranitromethane [Methane, 10,000 b
tetranitro-].
542-88-1............ Chloromethyl ether 1,000 b
[Methane, oxybis[chloro-].
556-64-9............ Methyl thiocyanate 20,000 b
[Thiocyanic acid, methyl
ester].
584-84-9............ Toluene 2,4-diisocyanate 10,000 a
[Benzene, 2,4-diisocyanato-
1-methyl-]\1\.
594-42-3............ Perchloromethylmercaptan 10,000 b
[Methanesulfenyl chloride,
trichloro-].
624-83-9............ Methyl isocyanate [Methane, 10,000 a, b
isocyanato-].
814-68-6............ Acrylyl chloride [2- 5,000 b
Propenoyl chloride].
4170-30-3........... Crotonaldehyde [2-Butenal]. 20,000 b
7446-09-5........... Sulfur dioxide (anhydrous). 5,000 a, b
7446-11-9........... Sulfur trioxide............ 10,000 a, b
7550-45-0........... Titanium tetrachloride 2,500 b
[Titanium chloride (TiCl4)
(T-4)-].
7637-07-2........... Boron trifluoride [Borane, 5,000 b
trifluoro-].
7647-01-0........... Hydrochloric acid (conc 30% 15,000 d
or greater).
7647-01-0........... Hydrogen chloride 5,000 a
(anhydrous) [Hydrochloric
acid].
7664-39-3........... Hydrogen fluoride/ 1,000 a, b
Hydrofluoric acid (conc
50% or greater)
[Hydrofluoric acid].
7664-41-7........... Ammonia (anhydrous)........ 10,000 a, b
7664-41-7........... Ammonia (conc 20% or 20,000 a, b
greater).
7697-37-2........... Nitric acid (conc 80% or 15,000 b
greater).
7719-12-2........... Phosphorus trichloride 15,000 b
[Phosphorous trichloride].
7726-95-6........... Bromine.................... 10,000 a, b
7782-41-4........... Fluorine................... 1,000 b
7782-50-5........... Chlorine................... 2,500 a, b
7783-06-4........... Hydrogen sulfide........... 10,000 a, b
7783-07-5........... Hydrogen selenide.......... 500 b
7783-60-0........... Sulfur tetrafluoride 2,500 b
[Sulfur fluoride (SF4), (T-
4)-].
7784-34-1........... Arsenous trichloride....... 15,000 b
7784-42-1........... Arsine..................... 1,000 b
7803-51-2........... Phosphine.................. 5,000 b
8014-95-7........... Oleum (Fuming Sulfuric 10,000 e
acid) [Sulfuric acid,
mixture with sulfur
trioxide]\1\.
10025-87-3.......... Phosphorus oxychloride 5,000 b
[Phosphoryl chloride].
10049-04-4.......... Chlorine dioxide [Chlorine 1,000 c
oxide (ClO2)].
10102-43-9.......... Nitric oxide [Nitrogen 10,000 b
oxide (NO)].
10294-34-5.......... Boron trichloride [Borane, 5,000 b
trichloro-].
13463-39-3.......... Nickel carbonyl............ 1,000 b
13463-40-6.......... Iron, pentacarbonyl- [Iron 2,500 b
carbonyl (Fe(CO)5), (TB-5-
11)-].
19287-45-7.......... Diborane................... 2,500 b
26471-62-5.......... Toluene diisocyanate 10,000 a
(unspecified isomer)
[Benzene, 1,3-
diisocyanatomethyl-1]\1\.
------------------------------------------------------------------------
\1\The mixture exemption in Sec. 68.115(b)(1) does not apply to the
substance.
Note: Basis for Listing:
aMandated for listing by Congress.
bOn EHS list, vapor pressure 10 mmHg or greater.
cToxic gas.
eToxicity of sulfur trioxide and sulfuric acid, potential to release
sulfur trioxide, and history of accidents.
Table 3 to Sec. 68.130.--List of Regulated Flammable Substances and
Threshold Quantities for Accidental Release Prevention
[Alphabetical Order--63 Substances]
------------------------------------------------------------------------
Threshold
Chemical name CAS No. quantity Basis for
(lbs) listing
------------------------------------------------------------------------
Acetaldehyde..................... 75-07-0 10,000 g
Acetylene [Ethyne]............... 74-86-2 10,000 f
Bromotrifluorethylene [Ethene, 598-73-2 10,000 f
bromotrifluoro-].
1,3-Butadiene.................... 106-99-0 10,000 f
Butane........................... 106-97-8 10,000 f
1-Butene......................... 106-98-9 10,000 f
2-Butene......................... 107-01-7 10,000 f
Butene........................... 25167-67-3 10,000 f
2-Butene-cis..................... 590-18-1 10,000 f
2-Butene-trans [2-Butene, (E)]... 624-64-6 10,000 f
Carbon oxysulfide [Carbon oxide 463-58-1 10,000 f
sulfide (COS)].
Chlorine monoxide [Chlorine 7791-21-1 10,000 f
oxide].
2-Chloropropylene [1-Propene, 2- 557-98-2 10,000 g
chloro-].
1-Chloropropylene [1-Propene, 1- 590-21-6 10,000 g
chloro-].
Cyanogen [Ethanedinitrile]....... 460-19-5 10,000 f
Cyclopropane..................... 75-19-4 10,000 f
Dichlorosilane [Silane, dichloro- 4109-96-0 10,000 f
].
Difluoroethane [Ethane, 1,1- 75-37-6 10,000 f
difluoro-].
Dimethylamine [Methanamine, N- 124-40-3 10,000 f
methyl-].
2,2-Dimethylpropane [Propane, 2,2- 463-82-1 10,000 f
dimethyl-].
Ethane........................... 74-84-0 10,000 f
Ethyl acetylene [1-Butyne]....... 107-00-6 10,000 f
Ethylamine [Ethanamine].......... 75-04-7 10,000 f
Ethyl chloride [Ethane, chloro-]. 75-00-3 10,000 f
Ethylene [Ethene]................ 74-85-1 10,000 f
Ethyl ether [Ethane, 1,1'-oxybis- 60-29-7 10,000 g
].
Ethyl mercaptan [Ethanethiol].... 75-08-1 10,000 g
Ethyl nitrite [Nitrous acid, 109-95-5 10,000 f
ethyl ester].
Hydrogen......................... 1333-74-0 10,000 f
Isobutane [Propane, 2-methyl].... 75-28-5 10,000 f
Isopentane [Butane, 2-methyl-]... 78-78-4 10,000 g
Isoprene [1,3-Butadinene, 2- 78-79-5 10,000 g
methyl-].
Isopropylamine [2-Propanamine]... 75-31-0 10,000 g
Isopropyl chloride [Propane, 2- 75-29-6 10,000 g
chloro-].
Methane.......................... 74-82-8 10,000 f
Methylamine [Methanamine]........ 74-89-5 10,000 f
3-Methyl-1-butene................ 563-45-1 10,000 f
2-Methyl-1-butene................ 563-46-2 10,000 g
Methyl ether [Methane, oxybis-].. 115-10-6 10,000 f
Methyl formate [Formic acid, 107-31-3 10,000 g
methyl ester].
2-Methylpropene [1-Propene, 2- 115-11-7 10,000 f
methyl-].
1,3-Pentadinene.................. 504-60-9 10,000 f
Pentane.......................... 109-66-0 10,000 g
1-Pentene........................ 109-67-1 10,000 g
2-Pentene, (E)-.................. 646-04-8 10,000 g
2-Pentene, (Z)-.................. 627-20-3 10,000 g
Propadiene [1,2-Propadiene]...... 463-49-0 10,000 f
Propane.......................... 74-98-6 10,000 f
Propylene [1-Propene]............ 115-07-1 10,000 f
Propyne [1-Propyne].............. 74-99-7 10,000 f
Silane........................... 7803-62-5 10,000 f
Tetrafluoroethylene [Ethene, 116-14-3 10,000 f
tetrafluoro-].
Tetramethylsilane [Silane, 75-76-3 10,000 g
tetramethyl-].
Trichlorosilane [Silane, 10025-78-2 10,000 g
trichloro-].
Trifluorochloroethylene [Ethene, 79-38-9 10,000 f
chlorotrifluoro-].
Trimethylamine [Methanamine, N,N- 75-50-3 10,000 f
dimethyl-].
Vinyl acetylene [1-Buten-3-yne].. 689-97-4 10,000 f
Vinyl chloride [Ethene, chloro-]. 75-01-4 10,000 a, f
Vinyl ethyl ether [Ethene, ethoxy- 109-92-2 10,000 g
].
Vinyl fluoride [Ethene, fluoro-]. 75-02-5 10,000 f
Vinylidene chloride [Ethene, 1,1- 75-35-4 10,000 g
dichloro-].
Vinylidene fluoride [Ethene, 1,1- 75-38-7 10,000 f
difluoro-].
Vinyl methyl ether [Ethene, 107-25-5 10,000 f
methoxy-].
------------------------------------------------------------------------
Note: Basis for Listing:
aMandated for listing by Congress.
fFlammable gas.
gVolatile flammable liquid.
Table 4 to Sec. 68.130.--List of Regulated Flammable Substances and Threshold Quantities for Accidental Release
Prevention
[CAS Number Order--63 Substances]
----------------------------------------------------------------------------------------------------------------
Threshold
CAS No. Chemical name CAS No. quantity Basis for
(lbs) listing
----------------------------------------------------------------------------------------------------------------
60-29-7............. Ethyl ether [Ethane, 1,1'-oxybis-]................. 60-29-7 10,000 g
74-82-8............. Methane............................................ 74-82-8 10,000 f
74-84-0............. Ethane............................................. 74-84-0 10,000 f
74-85-1............. Ethylene [Ethene].................................. 74-85-1 10,000 f
74-86-2............. Acetylene [Ethyne]................................. 74-86-2 10,000 f
74-89-5............. Methylamine [Methanamine].......................... 74-89-5 10,000 f
74-98-6............. Propane............................................ 74-98-6 10,000 f
74-99-7............. Propyne [1-Propyne]................................ 74-99-7 10,000 f
75-00-3............. Ethyl chloride [Ethane, chloro-]................... 75-00-3 10,000 f
75-01-4............. Vinyl chloride [Ethene, chloro-]................... 75-01-4 10,000 a, f
75-02-5............. Vinyl fluoride [Ethene, fluoro-]................... 75-02-5 10,000 f
75-04-7............. Ethylamine [Ethanamine]............................ 75-04-7 10,000 f
75-07-0............. Acetaldehyde....................................... 75-07-0 10,000 g
75-08-1............. Ethyl mercaptan [Ethanethiol]...................... 75-08-1 10,000 g
75-19-4............. Cyclopropane....................................... 75-19-4 10,000 f
75-28-5............. Isobutane [Propane, 2-methyl]...................... 75-28-5 10,000 f
75-29-6............. Isopropyl chloride [Propane, 2-chloro-]............ 75-29-6 10,000 g
75-31-0............. Isopropylamine [2-Propanamine]..................... 75-31-0 10,000 g
75-35-4............. Vinylidene chloride [Ethene, 1,1-dichloro-]........ 75-35-4 10,000 g
75-37-6............. Difluoroethane [Ethane, 1,1-difluoro-]............. 75-37-6 10,000 f
75-38-7............. Vinylidene fluoride [Ethene, 1,1-difluoro-]........ 75-38-7 10,000 f
75-50-3............. Trimethylamine [Methanamine, N, N-dimethyl-]....... 75-50-3 10,000 f
75-76-3............. Tetramethylsilane [Silane, tetramethyl-]........... 75-76-3 10,000 g
78-78-4............. Isopentane [Butane, 2-methyl-]..................... 78-78-4 10,000 g
78-79-5............. Isoprene [1,3,-Butadiene, 2-methyl-]............... 78-79-5 10,000 g
79-38-9............. Trifluorochloroethylene [Ethene, chlorotrifluoro-]. 79-38-9 10,000 f
106-97-8............ Butane............................................. 106-97-8 10,000 f
106-98-9............ 1-Butene........................................... 106-98-9 10,000 f
196-99-0............ 1,3-Butadiene...................................... 106-99-0 10,000 f
107-00-6............ Ethyl acetylene [1-Butyne]......................... 107-00-6 10,000 f
107-01-7............ 2-Butene........................................... 107-01-7 10,000 f
107-25-5............ Vinyl methyl ether [Ethene, methoxy-].............. 107-25-5 10,000 f
107-31-3............ Methyl formate [Formic acid, methyl ester]......... 107-31-3 10,000 g
109-66-0............ Pentane............................................ 109-66-0 10,000 g
109-67-1............ 1-Pentene.......................................... 109-67-1 10,000 g
109-92-2............ Vinyl ethyl ether [Ethene, ethoxy-]................ 109-92-2 10,000 g
109-95-5............ Ethyl nitrite [Nitrous acid, ethyl ester].......... 109-95-5 10,000 f
115-07-1............ Propylene [1-Propene].............................. 115-07-1 10,000 f
115-10-6............ Methyl ether [Methane, oxybis-].................... 115-10-6 10,000 f
115-11-7............ 2-Methylpropene [1-Propene, 2-methyl-]............. 115-11-7 10,000 f
116-14-3............ Tetrafluoroethylene [Ethene, tetrafluoro-]......... 116-14-3 10,000 f
124-40-3............ Dimethylamine [Methanamine, N-methyl-]............. 124-40-3 10,000 f
460-19-5............ Cyanogen [Ethanedinitrile]......................... 460-19-5 10,000 f
463-49-0............ Propadiene [1,2-Propadiene]........................ 463-49-0 10,000 f
463-58-1............ Carbon oxysulfide [Carbon oxide sulfide (COS)]..... 463-58-1 10,000 f
463-82-1............ 2,2-Dimethylpropane [Propane, 2,2-dimethyl-]....... 463-82-1 10,000 f
504-60-9............ 1,3-Pentadiene..................................... 504-60-9 10,000 f
557-98-2............ 2-Chloropropylene [1-Propene, 2-chloro-]........... 557-98-2 10,000 g
563-45-1............ 3-Methyl-1-butene.................................. 563-45-1 10,000 f
563-46-2............ 2-Methyl-1-butene.................................. 563-46-2 10,000 g
590-18-1............ 2-Butene-cis....................................... 590-18-1 10,000 f
590-21-6............ 1-Chloropropylene [1-Propene, 1-chloro-]........... 590-21-6 10,000 g
598-73-2............ Bromotrifluorethylene [Ethene, bromotrifluoro-].... 598-73-2 10,000 f
624-64-6............ 2-Butene-trans [2-Butene, (E)]..................... 624-64-6 10,000 f
627-20-3............ 2-Pentene, (Z)-.................................... 627-20-3 10,000 g
646-04-8............ 2-Pentene, (E)-.................................... 646-04-8 10,000 g
689-97-4............ Vinyl acetylene [1-Buten-3-yne].................... 689-97-4 10,000 f
1333-74-0........... Hydrogen........................................... 1333-74-0 10,000 f
4109-96-0........... Dichlorosilane [Silane, dichloro-]................. 4109-96-0 10,000 f
7791-21-1........... Chlorine monoxide [Chlorine oxide]................. 7791-21-1 10,000 f
7803-62-5........... Silane............................................. 7803-62-5 10,000 f
10025-78-2.......... Trichlorosilane [Silane,trichloro-]................ 10025-78-2 10,000 g
25167-67-3.......... Butene............................................. 25167-67-3 10,000 f
----------------------------------------------------------------------------------------------------------------
Note: Basis for Listing:aMandated for listing by Congress.fFlammable gas.gVolatile flammable liquid.
[FR Doc. 94-1556 Filed 1-28-94; 8:45 am]
BILLING CODE 6560-50-P