[Federal Register Volume 63, Number 86 (Tuesday, May 5, 1998)]
[Notices]
[Pages 24782-24784]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-11874]
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ENVIRONMENTAL PROTECTION AGENCY
[FRL-6009-8]
National Ambient Air Quality Standards for Sulfur Oxides (Sulfur
Dioxide); Intervention Level Program
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.
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[[Page 24783]]
SUMMARY: The EPA is announcing today the following actions:
(1) The schedule for responding to the remand of the final decision
on the national ambient air quality standards (NAAQS) for sulfur
dioxide (SO2) published on May 22, 1996, and any final
action on the proposed intervention level program (ILP) for the
reduction of SO2 emissions published on January 2, 1997.
(2) The interim actions EPA will take to address 5-minute peak
SO2 levels that may pose risk to sensitive asthmatic
individuals.
(3) The solicitation of comments and associated information and
analyses on 5-minute peak SO2 concentrations in the ambient
air, with emphasis on the characterization of the likelihood of
exposure of sensitive asthmatic individuals to peak SO2
concentrations at 0.6 parts per million (ppm) and above during
exercise.
DATES: (1) The EPA will propose its response to the SO2
NAAQS remand for public comment in the summer of 1999 and take final
action no later than December 2000. The EPA will take any final action
on the proposed ILP, consistent with its final action on the
SO2 NAAQS, no later than December 2000.
(2) In the interim, until such final actions are taken, EPA will
now begin taking actions to address known problem areas with high 5-
minute peak SO2 levels that may pose risk to sensitive
asthmatic individuals.
(3) Comments and associated information and analyses should be
submitted on or before November 1, 1998.
ADDRESSES: Comments and associated information and analyses should be
submitted to Ms. Susan Lyon Stone, U.S. Environmental Protection
Agency, MD-15, Research Triangle Park, NC 27711.
FOR FURTHER INFORMATION CONTACT: Ms. Susan Lyon Stone at the above
address or telephone (919) 541-1146 on matters pertaining to 5-minute
peak SO2 levels and the SO2 NAAQS remand. For
information on the interim actions EPA plans to take to address 5-
minute peak SO2 levels and the ILP, contact Mr. Eric Crump
at the same address or telephone (919) 541-4719.
SUPPLEMENTARY INFORMATION:
On May 22, 1996, EPA announced its final decision that revisions of
the SO2 NAAQS were not appropriate (61 FR 25566). At issue
in making that decision was whether a new 5-minute NAAQS was
appropriate to protect sensitive asthmatic individuals from the risk
posed by exposure to 5-minute SO2 levels of 0.6 ppm or
above. Given the available health effects information; information as
to the localized, infrequent, and site-specific nature of risk
involved; and the advice of the Clean Air Scientific Advisory Committee
(CASAC), the Administrator concluded that short-term peak
concentrations of SO2 do not constitute the type of
ubiquitous public health problem for which the establishment of a NAAQS
would be appropriate.
Because of the localized, infrequent, and site-specific nature of
the risk, as characterized in its final decision notice (61 FR 25575-
25576), the Administrator further concluded that the residual health
risk posed by short-term SO2 concentrations remaining after
attainment of the current SO2 NAAQS are most appropriately
addressed by the States. It was the Administrator's judgment that the
States are in a far better position than EPA to assess the highly
localized and site-specific factors that determine whether occurrences
of 5-minute peak SO2 concentrations in a given area pose a
significant risk to sensitive asthmatic individuals in the local
population, and if so, to fashion an appropriate remedial response. In
light of its characterization of the nature of 5-minute peak
SO2 concentrations and the likelihood that these peaks would
result in exposure conditions that could cause significant health
effects in sensitive asthmatic individuals during exercise, EPA also
announced that it intended to propose a new program and associated
guidance to assist States in determining whether 5-minute peak
concentrations of SO2 in the range of 0.6 ppm to 2.0 ppm
posed a significant health risk to sensitive asthmatic individuals in
the local population, and if so, to identify appropriate remedial
responses. Consistent with its final SO2 NAAQS decision, EPA
subsequently proposed for comment the intervention level program (ILP)
for the reduction of SO2 emissions on January 2, 1997 (62 FR
210). This proposed ILP was intended to supplement the protection
provided by the existing primary and secondary SO2 NAAQS.
A key element of the proposed ILP was the establishment (to be
codified in part 51 of the CFR) of a concern level of 0.6 ppm, 5-minute
average SO2 concentration, and an endangerment level of 2.0
ppm, 5-minute average. The proposed ILP would require that State and
tribal plans contain the authority to take whatever action is necessary
to prevent further exceedances of such concern and endangerment levels
when the State/tribe determines that intervention is appropriate. The
proposed ILP includes a discussion of the factors that the State/tribe
should consider in making such determinations, including the magnitude
and frequency of peak concentrations exceeding these levels, the
history and nature of any citizen complaints, available information on
potential exposure of sensitive asthmatic individuals, and information
about the source(s) causing the peak SO2 concentrations.
Based on the above factors, the proposed ILP provides for flexibility
for the State/tribe to determine the nature and degree of intervention
that is warranted in any area. The States/tribes are also given the
flexibility in the proposed ILP to relocate existing monitors to areas
where 5-minute peak concentrations may be of concern through changes to
SO2 monitoring requirements. The proposed ILP recognizes
that authority to take such actions, when justified on a case-by-case
basis, currently exists under section 303 of the Clean Air Act.
Building upon this authority, the proposed ILP codifies the health
benchmarks for such actions (i.e., the concern and endangerment levels)
and provides guidance to assist States/tribes in identifying and taking
appropriate actions.
SO2 NAAQS Remand
In July 1996, the American Lung Association and the Environmental
Defense Fund petitioned the District of Columbia Court of Appeals for
judicial review of EPA's decision not to establish a new 5-minute
NAAQS. On January 30, 1998, the court issued a decision in that case
American Lung Association v. Browner, No. 96-1251 (D.C. Cir.). The
court found that EPA failed to provide an adequate explanation for its
determination that no revision to the SO2 NAAQS was
appropriate. As a result, the court remanded the case to permit EPA to
more fully explain its decision not to set a standard for short-term
peak SO2 levels of 0.6 ppm or greater.
Schedule for EPA Final Actions
In remanding the case to EPA, the court did not establish a
deadline for EPA to take action consistent with the remand. In lieu of
pursuing further litigation to seek a court-ordered schedule for EPA's
response to the SO2 NAAQS remand, the petitioners in the
case initiated discussions with EPA to establish such a schedule for
EPA's response. Based on these discussions, it was agreed that EPA
would take final action no later than December 2000. In order to meet
this date for final action, EPA intends to propose for public comment
its response to the remand by
[[Page 24784]]
the summer of 1999. In conjunction with taking final action on its
response to the SO2 NAAQS remand, EPA also intends to take
any final action on the ILP no later than December 2000. In so doing,
EPA will draw upon its response to the remand on the SO2
NAAQS decision so as to ensure consistency between these actions.
Interim Actions
Between now and when final action on the SO2 NAAQS
remand and the ILP is taken, EPA intends to work with States/tribes
with known areas of high 5-minute peak SO2 concentrations to
undertake a number of actions. These actions include the following:
determining whether the existing SO2 NAAQS and State
Implementation Plan (SIP) requirements are being met in such areas;
taking regulatory action in such areas where appropriate (e.g., SIP
calls); and initiating enforcement review/action to ensure SIP
requirements are met. The EPA also plans to issue monitoring and other
guidance to States/tribes/regions to assist them in identifying and
addressing high 5-minute peak problems.
Solicitation of Information on 5-Minute Peak SO2
Concentrations
To supplement its current information on 5-minute peak
SO2 concentrations and exposures of sensitive asthmatic
individuals to peak levels of concern, EPA is soliciting comments and
associated information and analyses on such 5-minute peak
SO2 concentrations. The EPA will consider this information
in the context of the interim actions described above and in its
response to the remand and in its final ILP decision. More
specifically, EPA solicits information and analyses on the following:
sources or source types and the nature of events that are most likely
to give rise to short-term peak SO2 levels; the magnitude
and frequency of such peaks; the time of day of the occurrence of such
peaks; meteorological conditions in the area in which such peaks occur;
the density of the population near the source(s) involved; and the
frequency with which asthmatic individuals would likely be exposed to
peak SO2 concentrations at 0.60 ppm and above while at
elevated ventilation rates (i.e., during exercise).
Dated: April 29, 1998.
Richard D. Wilson,
Acting Assistant Adminstrator for Air and Radiation.
[FR Doc. 98-11874 Filed 5-4-98; 8:45 am]
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