[Federal Register Volume 76, Number 17 (Wednesday, January 26, 2011)]
[Rules and Regulations]
[Pages 4780-4800]
[FR Doc No: 2011-1353]

Vol. 76

Wednesday,

No. 17

January 26, 2011

Part III

Environmental Protection Agency

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40 CFR Parts 50, 53 and 58

Denial of the Petitions To Reconsider the Final Rule Promulgating the
Primary National Ambient Air Quality Standard for Sulfur Dioxide; Final
Rule

Federal Register / Vol. 76, No. 17 / Wednesday, January 26, 2011 /
Rules and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 50, 53 and 58

[EPA-HQ-OAR-2007-0352; FRL-9255-7]

Denial of the Petitions To Reconsider the Final Rule Promulgating
the Primary National Ambient Air Quality Standard for Sulfur Dioxide

AGENCY: Environmental Protection Agency (EPA).

ACTION: Denial of petitions to reconsider.

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SUMMARY: The Environmental Protection Agency (EPA, or Agency) is
denying the petitions to reconsider the final revised primary national
ambient air quality standard (NAAQS) for oxides of sulfur as measured
by sulfur dioxide (SO2) issued under section 109 of the
Clean Air Act (CAA). The final revised SO2 Primary NAAQS was
published on June 22, 2010, and became effective on August 23, 2010.
EPA has carefully reviewed all of the petitions and revisited both the
rulemaking record and the Administrator's decision process underlying
the final revised SO2 Primary NAAQS in light of these
petitions. EPA's analysis of the petitions reveals that the petitions
have provided inadequate and generally irrelevant arguments and
evidence that the underlying information supporting the final revised
SO2 Primary NAAQS is flawed, misinterpreted or
inappropriately applied by EPA. The petitioners' arguments fail to meet
the criteria for reconsideration under the Clean Air Act.

DATES: This denial is effective January 14, 2011.

ADDRESSES: EPA's docket for this action is Docket ID No. EPA-HQ-OAR-
2007-0352. All documents in the docket are listed on the http://www.regulations.gov Web site. Although listed in the index, some
information is not publicly available, e.g., confidential business
information (CBI) or other information where disclosure is restricted
by statute. Certain other material, such as copyrighted material, is
not placed on the Internet and will be publicly available only in hard
copy form. Publicly available docket materials are available either
electronically through http://www.regulations.gov or in hard copy at
EPA's Docket Center, Public Reading Room, EPA West Building, Room 3334,
1301 Constitution Avenue, NW., Washington, DC 20004. This Docket Center
is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding
legal holidays. The telephone number for the Public Reading Room is
(202) 566-1744, and the telephone number for the Air Docket is (202)
566-1742.

FOR FURTHER INFORMATION CONTACT: Dr. Michael J. Stewart, Health and
Environmental Impacts Division, Office of Air Quality Planning and
Standards, U.S. Environmental Protection Agency, Mail code C504-06,
Research Triangle Park, NC 27711; telephone:<PHONE_NUMBER>; fax (919)
541-0237; e-mail<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Table of Contents

    The following topics are discussed in this document:

I. Introduction
    A. Summary
    B. Background
    1. Revisions to the SO2 Primary NAAQS
    2. Preamble Discussion of Anticipated Approaches for
Implementation
    3. Petitions for Reconsideration and for Judicial Review and
Stay Requests
II. Standard for Reconsideration
III. Administrative Process Issues
    A. Summary of Petitioners' Arguments
    1. UARG
    2. NEDA/CAP
    3. ASARCO
    4. MSCC
    5. TCEQ
    6. North Dakota and South Dakota
    7. WVDEP
    8. ADEQ
    B. Responses to the Claims and Arguments Raised by the
Petitioners
    1. Petitioners' Objections Are to Agency Actions Which Are Not
Final
    2. EPA's Implementation Discussions Are Not of Central Relevance
to the Decisions on the Final Revised SO2 Primary NAAQS
    3. EPA's Implementation Discussions Were a Logical Outgrowth
From the Proposed Rule
    4. EPA Is Not Required To Promulgate Regulatory Requirements
Regarding NAAQS Implementation and May Discuss Implementation Issues
Through Non-Binding Guidance
IV. Statutory and Regulatory Issues
    A. Summary of Petitioners' Arguments
    1. Consistency With ``Cooperative Federalism'' of CAA
    2. Consistency With CAA Section 107(d) Designations Requirements
    3. Consistency With CAA Section 110(a) SIP Planning Requirements
    4. Consistency With CAA Section 171(2) Definition of
``Nonattainment Area''
    5. Consistency With SO2 Primary NAAQS Regulatory Text
    B. Responses to the Petitioners' Statutory and Regulatory
Arguments
V. Impact on Final Standard Issue
    A. Petitioners' Claims
    B. EPA's Response
VI. Stay of Final Rule Issue
    A. Summary of Petitioners' Administrative Requests
    B. EPA's Response to the Administrative Requests
VII. Conclusion

I. Introduction

A. Summary

    This is EPA's response denying the petitions to reconsider the
final revised SO2 Primary NAAQS promulgated under Section
109 of the Clean Air Act (CAA, or Act) (75 FR 35520, June 22, 2010).
EPA has considered all of the petitions, including the arguments
presented therein and information provided by the petitioners as
supporting evidence of their claims, and including materials submitted
to the District of Columbia Circuit Court of Appeals that petitioners
provided regarding the same or similar claims raised there in support
of motions to stay the revised SO2 Primary NAAQS. EPA has
evaluated the merit of the petitioners' arguments in the context of the
entire body of scientific and other evidence before the Agency. This
response provides EPA's justifications for denying these petitions.
Sections III-VI of this Decision set forth EPA's specific responses to
the petitioners' arguments.
    After a comprehensive, careful review and analysis of the
petitions, EPA has determined that the petitioners' arguments and
evidence are inadequate, irrelevant to the promulgation of the final
revised SO2 Primary NAAQS, and do not show that the
underlying information supporting the revised SO2 Primary
NAAQS is flawed, misinterpreted by EPA, or inappropriately applied by
EPA. In fact, petitioners do not challenge the revised health-based
SO2 Primary NAAQS at all. The focus of their petitions is,
instead, EPA's non-binding preamble discussion providing guidance
regarding expected approaches for future implementation of the revised
SO2 Primary NAAQS, which they claim should not have been
presented without first having undergone notice and comment procedures.
They claim that this discussion relates to aspects of the revised
SO2 Primary NAAQS that are of ``central relevance'' to the
NAAQS decision itself, and as such have an impact on the promulgated
NAAQS. The fact that EPA did not present this discussion in the notice
of proposed rulemaking (NPRM), petitioners argue, violates the
procedural requirements of the Clean Air Act and requires EPA to
reconsider the promulgated rule. Moreover, petitioners argue that the
discussion in the final rule preamble conflicts with numerous
substantive provisions of the Act, as well as the

regulatory text of the final NAAQS. Therefore, petitioners claim, EPA
must stay the effectiveness of the revised SO2 Primary
NAAQS, pending the Agency's reconsideration of the preamble discussion
and of the promulgated NAAQS.
    As discussed in detail throughout this decision, petitioners'
claims and the information they submit do not change or undermine our
scientific conclusions regarding the appropriateness of the revisions
to the SO2 Primary NAAQS, as determined under section 109 of
the CAA. Nor do they change or undermine our conclusions regarding the
promulgated requirements for an SO2 monitoring network or
the conforming regulatory changes we made to the Air Quality Index
(AQI). More specifically, the arguments in the petitions do not lead
EPA to change its final decisions regarding the need to revise the
prior SO2 Primary NAAQS, and what those revisions should be.
EPA's decisions were based on a thorough review in the Integrated
Science Assessment for Oxides of Sulfur--Health Criteria (ISA) of
scientific information on known and potential human health effects
associated with exposure to SO2 in the air. Those final
decisions also took into account: (1) EPA's Risk and Exposure
Assessment to Support the Review of the SO2 Primary National
Ambient Air Quality Standard (REA), which provided quantitative
exposure and risk analyses based on the ISA; (2) advice and
recommendations of the statutory review body, the Clean Air Act Science
Advisory Committee (CASAC), as reflected in its letters to the
Administrator and its public discussions of the ISA and REA; (3) public
comments received during the development of the ISA and REA; and (4)
public comments received on EPA's NPRM for the revised SO2
Primary NAAQS.
    A core defect in petitioners' arguments is that they are not based
on consideration of the body of scientific information that informed
EPA's final decisions in promulgating the revised SO2
Primary NAAQS. In fact, petitioners' arguments have nothing at all to
do with EPA's scientific conclusions, and provide no new information or
basis for EPA to revisit either those conclusions or the specific
SO2 Primary NAAQS that EPA promulgated. Petitioners'
objections regarding the final rule preamble's non-binding discussion
of anticipated future implementation approaches are neither relevant to
nor persuasive in challenging EPA's promulgated revised SO2
Primary NAAQS. They certainly are not material or a reliable basis on
which to question the validity and credibility of the body of science
underlying EPA's SO2 NAAQS decision, or the decision process
as articulated in the NPRM and final rulemaking notice. Petitioners'
assertions regarding the additional preamble discussion providing
guidance on expected future and separate implementation actions are
thus not an appropriate basis on which to challenge the voluminous and
well documented body of science that is the technical foundation of
EPA's revised SO2 Primary NAAQS.
    A second, and equally important, defect in petitioners' arguments
is their assumption that EPA's non-binding preamble discussion of
anticipated approaches for separate future implementation actions
constituted, itself, final agency action governing those future
actions. Although petitioners do not demonstrate how EPA's discussion
has such final, binding and enforceable effect, their implicit
assumption is that EPA has already taken final rulemaking action on the
discussed implementation approaches. Only if EPA had taken such final
action on these discussed approaches could there possibly be an issue
regarding whether EPA's discussion was a ``logical outgrowth'' of the
proposed rule, and whether it was of ``central relevance'' to the
promulgated revised SO2 Primary NAAQS sufficient to support
a petition for reconsideration. Similarly, for the discussion to
constitute a ``procedural error,'' it would first have to represent a
``determination'' under section 307(d) that is a final rulemaking
action. But the preamble discussion at issue was not such a final
agency action. EPA plainly stated that the discussion represented non-
binding guidance regarding future actions, that the Agency's
anticipated approach could continue to evolve as further guidance is
developed, and that the Agency expected there to be circumstances in
which the anticipated approaches may not apply. In other words,
regarding the implementation discussion, EPA has not yet taken a final
action that could be ``reconsidered.''
    Even assuming, for the sake of argument, that EPA's implementation
discussion as presented in the final preamble to the SO2
Primary NAAQS could have constituted final action, it is separate and
independent from the establishment of the health-based SO2
Primary NAAQS itself. Therefore, the Agency does not regard the
discussion as having been of ``central relevance'' to the regulatory
decision on the NAAQS itself. In setting NAAQS that are ``requisite''
to protect public health with an adequate margin of safety, as provided
in section 109(b) of the Act, EPA's task is to establish standards that
are neither more nor less stringent than necessary for these purposes.
In so doing, EPA may not consider costs of implementing the standards.
Whitman v. American Trucking Associations, 531 U.S. 457, 471, 475-76
(2001). Petitioners frequently assert that the implementation
discussion is an ``aspect'' of the final NAAQS itself, but this is
incorrect given that issues regarding future implementation are not
part of the NAAQS itself and are legally irrelevant to the setting of
the NAAQS. At most, the preamble's discussion of modeling partly
influenced only the reduced scope of the promulgated required
monitoring network, compared to that proposed, and no petitioner has
objected to that reduction. Consequently, we reject petitioners'
assertions that the non-binding preamble discussion of the anticipated
future implementation approaches, even if ``final action,'' is ``of
central relevance'' to the promulgation of the SO2 Primary
NAAQS, and therefore conclude that reconsideration of the rule in light
of that discussion is not warranted.
    Assuming again for the purpose of argument that the preamble's non-
binding implementation discussion could be both ``final action'' and
``of central relevance'' to the outcome of the NAAQS decision, we
further disagree with petitioners' claims that the discussion was not a
``logical outgrowth'' of the proposal and that the CAA required us to
present the discussion in the NPRM before we could address the expected
implementation approaches in the final rule's preamble or in other
guidance documents. Although the NPRM did not specifically address the
modeling based approach to implementation discussed in the preamble to
the final rule, it has long been EPA's practice in implementing the
prior SO2 Primary NAAQS to rely upon both modeling and
monitoring to determine whether areas have attained the NAAQS. To the
extent the preamble discussion in the NPRM concerning a monitoring
based approach was interpreted by interested parties to announce a
proposed change to that longstanding practice, the context for this
proposed change was the past practice of the Agency and the rulemaking
process inherently leaves open the possibility that an agency will
choose not to adopt any proposed change to its historic practice.
Therefore, interested parties should have foreseen that EPA might not,
in fact, ``promulgate'' any such change but instead discuss our
expectation to continue our historic practice, and they

had ample opportunity to comment on that possibility. In fact,
interested parties did comment on the related issue of the burden of
relying on monitoring, and suggested that EPA instead use modeling to
relieve that administrative burden. Partly in response to those
comments, EPA explained its anticipated approaches of continuing to
rely upon both modeling and monitoring in implementing the Primary
SO2 NAAQS, and made clear that except for the promulgated
provisions relating to the scope of the monitoring network and
associated requirements, the Agency was still developing its policy for
future implementation actions such as area designations and
determinations of NAAQS attainment, and would decide whether to base
such actions on modeling or monitoring in the future on a case-by-case
basis. Thus, although EPA disagrees with the petitioners' view that the
non-binding preamble discussion on future implementation represents
final agency action of central relevance to the NAAQS decision, even if
the preamble to the final rule has this effect, EPA committed no
procedural error in presenting this discussion in the final rule's
preamble, and reconsideration is not warranted.
    Furthermore, EPA disagrees with petitioners' assertions that the
Agency is required under the CAA to promulgate, as regulatory
provisions, requirements addressing future implementation of the NAAQS
of the type that petitioners demand. Nothing in the CAA requires this,
and the rulemaking for prior SO2 Primary NAAQS did not
contain such regulatory requirements. Consequently, we disagree with
petitioners' claims that it is now improper to continue to address
implementation issues in non-binding guidance such as that which EPA
has frequently issued regarding SO2 NAAQS implementation and
which EPA presented in the final rule preamble. Although the preamble's
inclusion of such guidance and statements regarding the intent to issue
further guidance do not warrant reconsideration of the final rule, we
fully expect to continue to evaluate implementation issues as we
proceed to develop such non-binding guidance and take implementing
actions.
    In addition to petitioners' administrative process arguments, EPA
disagrees with petitioners' claims that the final rule preamble's non-
binding implementation discussion is inconsistent with applicable
substantive CAA statutory provisions or with the regulatory text of the
SO2 Primary NAAQS. Petitioners present a series of arguments
claiming that our explanation of our anticipated approaches for area
designations and action on state implementation plan (SIP) submissions
unlawfully conflicts with the principles of ``cooperative federalism''
embraced by the CAA and with provisions and past practice under, for
example, CAA sections 107(d), 110(a), 171(2), and the promulgated
regulatory text of 40 CFR 50.17(b) and (c) and Appendix T section 1.1.
As we explain in section IV below, none of petitioners' arguments has
merit or warrants reconsideration of the final rule. Moreover,
petitioners must necessarily wait for final agency action to challenge
whatever implementation approaches EPA eventually adopts when making
designations and taking SIP actions. Moreover, we continue to believe
the implementation approaches discussed in the final rule preamble, if
taken in future final actions, would be consistent with governing
statutory and regulatory provisions. Of course, if public comments we
receive on those future actions persuade us otherwise, we would
consider taking other approaches and nothing EPA has done or stated to
this point forecloses ultimate adoption of entirely different
approaches. The very fact that future actions will provide us this
opportunity to refine and otherwise change our anticipated approaches
in advance of taking final action to make them binding shows that
reconsideration of them under CAA section 307(d)(7)(B), at this
preliminary stage, is not warranted. Nor are these objections ``of
central relevance'' to the outcome of the final SO2 Primary
NAAQS. Thus, they do not meet the criteria for reconsideration under
CAA section 307(d)(7)(B).
    For similar reasons, discussed further in Section V, we disagree
with petitioners' claims that the non-binding implementation discussion
has any ``impact'' on the promulgated NAAQS. As the discussion does not
represent final agency action, it cannot have any direct and immediate
``impact'' on anything. Petitioners' objections on this point distill
to a claim that using modeling to determine whether areas are attaining
the SO2 Primary NAAQS would be more ``conservative'' and
could over-predict ambient SO2 concentrations in a specific
instance, resulting in more identified violations than if monitoring
were exclusively used. Of course, if such over-prediction were claimed
to occur in a given instance, interested parties would have a fair
opportunity to show that using modeling in that case may not be
appropriate. As explained in the preamble discussion, we believe that
the opposite is more likely to be true. The SO2 Primary
NAAQS itself is premised on the three-year average of the 99th
percentile of the daily maximum 1-hour average concentrations not
exceeding the level of the NAAQS in the ambient air. See 40 CFR
50.17(b) at 75 FR 35592. Modeling can very accurately identify areas of
potential daily maximum 1-hour concentrations above the NAAQS. See 75
FR at 35559. Accurate prediction of daily maximum 1-hour SO2
concentrations does not make the NAAQS more stringent, but, rather,
implements it faithfully.
    Finally, as further explained in section VI, EPA concludes that
there is no basis for an administrative stay of the final
SO2 Primary NAAQS. Under CAA section 307(d)(7)(B), EPA has
authority to issue a stay for up to three months if it grants a
petition to reconsider a final rule. As we are denying the petitions to
reconsider, an administrative stay here is not warranted. In addition,
a stay is not otherwise warranted. First, the petitioners have not made
a strong showing on the merits that reconsideration is warranted, for
all of the reasons upon which EPA is denying the petitions to
reconsider. Second, the petitioners' general and speculative arguments
concerning irreparable harm fail to account for the non-binding nature
of the final rule preamble's implementation discussion, the
opportunities for interested parties to assert their views in the
future implementation actions about which petitioners are concerned,
and also do not account for EPA's stated intention to provide further
implementation guidance. Third, petitioners are incorrect in
maintaining that it would be in the public interest to grant an
administrative stay of the rule. Their arguments ignore the harm to the
public that would occur from delayed implementation and attainment of
the revised SO2 Primary NAAQS, rendering such a stay
contrary to the public interest.

B. Background

1. Revisions to the SO2 Primary NAAQS
    Based on its review of the air quality criteria for oxides of
sulfur and the primary NAAQS for oxides of sulfur as measured by
SO2, EPA published a revised Primary SO2 NAAQS on
June 22, 2010, so that the standards are requisite to protect public
health with an adequate margin of safety, as appropriate under CAA
section 109. See 75 FR 35520-35603. Specifically, EPA replaced the
prior 24-hour and annual standards with a new one-hour SO2
standard at a level of 75 parts per billion (ppb), based on the three-
year average of

the annual 99th percentile of 1-hour daily maximum concentrations. EPA
also established requirements for an SO2 monitoring network
under section 110. See 75 FR at 35602. EPA did not, in this regulation,
promulgate requirements governing designations of areas as either
nonattainment, attainment or unclassifiable with respect to the revised
NAAQS under CAA section 107, or governing development and approval of
SIPs under CAA sections 110 and 192. Instead, for these future
implementation actions, EPA provided in the preamble non-binding
guidance regarding how the Agency initially expects to designate areas
under the new NAAQS and how the NAAQS would be implemented by States,
Tribes, local governments and EPA. See 75 FR at 35550-54, 35569-82. EPA
indicated that the Agency expected to provide additional guidance for
those future actions. Id.
    EPA revised the SO2 primary NAAQS pursuant to two
sections of the CAA that govern NAAQS establishment and revision.
Section 108 directs EPA to identify and list air pollutants that meet
certain criteria, including that the air pollutant ``in [the
Administrator's] judgment, cause[s] or contribute[s] to air pollution
which may reasonably be anticipated to endanger public health and
welfare'' and ``the presence of which in the ambient air results from
numerous or diverse mobile or stationary sources.'' CAA sections
108(a)(1). For those air pollutants listed, section 108 requires EPA to
issue air quality criteria that ``accurately reflect the latest
scientific knowledge useful in indicating the kind and extent of all
identifiable effects on public health or welfare which may be expected
from the presence of [a] pollutant in ambient air * * *'' CAA section
108(a)(2).
    Section 109(a) directs EPA to promulgate ``primary'' and
``secondary'' NAAQS for pollutants for which air quality criteria have
been issued. Section 109(b)(1) defines a primary standard as one ``the
attainment and maintenance of which in the judgment of the
Administrator, based on [the air quality] criteria and allowing an
adequate margin of safety, are requisite to protect the public
health.'' CAA section 109(b)(1). The legislative history of section 109
indicates that a primary NAAQS is to be set at ``the maximum
permissible ambient air level * * * which will protect the health of
any [sensitive] group of the population,'' and that for this purpose
``reference should be made to a representative sample of persons
comprising the sensitive group rather than to a single person in such a
group.'' S. Rep. No. 91-1196, 91st Cong., 2d Sess. 10 (1970). See also
American Lung Ass'n v. EPA, 134 F.3d 388, 389 (D.C. Cir. 1998) (``NAAQS
must protect not only average healthy individuals, but also `sensitive
citizens'--children, for example, or people with asthma, emphysema, or
other conditions rendering them particularly vulnerable to air
pollution. If a pollutant adversely affects the health of these
sensitive individuals, EPA must strengthen the entire national
standard.''); Coalition of Battery Recyclers Ass'n v. EPA, 604 F.3d
613, 617-18 (D.C. Cir. 2010) (same).
    The requirement that primary NAAQS include an adequate margin of
safety is intended to address uncertainties associated with
inconclusive scientific and technical information available at the time
of standard setting. It is also intended to provide a reasonable degree
of protection against hazards that research has not yet identified.
Lead Industries Ass'n v. EPA, 647 F.2d 1130, 1154 (D.C. Cir. 1980),
cert. denied, 449 U.S. 1042 (1980); American Petroleum Inst. v. Costle,
665 F.2d 1176, 1186 (D.C. Cir. 1981), cert. denied, 455 U.S. 1034
(1982). Thus, in selecting primary NAAQS, EPA may seek not only to
prevent pollution levels that have been demonstrated to be harmful but
also to prevent lower pollution levels that may pose an unacceptable
risk of harm, even if the risk is not precisely identified as to the
nature or degree.
    In addressing the requirement for a margin of safety, EPA considers
such factors as the nature and severity of the health effects involved,
the size of the at-risk population[s], and the kind and degree of the
uncertainties that must be addressed. In setting standards that are
``requisite'' to protect public health and welfare, as provided in
section 109(b), EPA's task is to establish standards that are neither
more nor less stringent than necessary for these purposes. In so doing,
EPA may not consider the costs of implementing the standards. Whitman
v. American Trucking Ass'n, 531 U.S. 457, 475-76 (2001). Consequently,
in establishing the revised SO2 Primary NAAQS, EPA did not
consider future implementation burdens or costs that might be borne by
industrial sources, States, Tribes, local governments, or by EPA
itself, such considerations not being relevant to the science based
determinations required to be made under CAA section 109. However, as
mentioned above, EPA did discuss and provide guidance on issues related
to future implementation, without such considerations impermissibly
affecting EPA's decision on the NAAQS itself.
    States are primarily responsible for ensuring attainment and
maintenance of NAAQS once EPA establishes them. Under CAA section 110
and related provisions, States submit, for EPA approval, SIPs that
provide for implementation, maintenance, enforcement, and attainment of
such standards through control programs directed to sources of the
pollutants involved. The States, in conjunction with EPA, also
administer the prevention of significant deterioration (PSD) program
under CAA sections 160-169 that covers these sources. In addition,
federal programs provide for nationwide control of emissions through:
The motor vehicle and motor vehicle fuel program under title II of the
CAA; the new source performance standards (NSPS) under CAA sections 111
and 129; and the acid rain program under CAA title IV. EPA has also
promulgated the Clean Air Interstate Rule (CAIR) to require additional
SO2 emission reductions needed in the eastern United States.
This rule was remanded by the U.S. Court of Appeals for the D.C.
Circuit, and EPA recently proposed revisions to it. See North Carolina
v. EPA, 531 F.3d 896 (D.C. Cir. 2008) and 75 FR 45210 (August 2, 2010).
EPA is also developing ``maximum achievable control technology'' (MACT)
standards under CAA sections 112 and 129 that the Agency expects will
result in significant SO2 reductions from the subject source
categories.
    EPA formally initiated the most recent review of the air quality
criteria for oxides of sulfur and of the SO2 Primary NAAQS
on May 15, 2006 (71 FR 29023). The first draft of the ISA for Oxides of
Sulfur-Health Criteria (ISA) and the Sulfur Dioxide Health Assessment
Plan: Scope and Methods for Exposure and Risk Assessment (EPA, 2007b)
were reviewed by CASAC at a public meeting held on December 5-6, 2007.
EPA then developed the second draft of the ISA and the first draft of
the Risk and Exposure Assessment to Support the Review of the
SO2 Primary [NAAQS] (REA), which CASAC reviewed at a public
meeting held on July 30-31, 2008. EPA released the final ISA in
September 2008 (EPA, 2008a). A second draft of the REA was reviewed by
CASAC at a public meeting held April 16-17, 2009. The final REA
containing the final staff policy assessment that considered the
evidence presented the final ISA and the air quality, exposure, and
risk characterization results as they related to the adequacy of the
then-current SO2 NAAQS and potential alternative primary
SO2 standards, was completed in August 2009 (EPA 2009a).
    On December 8, 2009, EPA published its proposed revisions to the
primary SO2 NAAQS. See 74 FR 64810. EPA

presented a number of conclusions, findings, and determinations
proposed by the Administrator, and invited general, specific, and/or
technical comments on all issues involved with this proposal, including
all such proposed judgments, conclusions, findings and determinations.
EPA carefully considered these comments as it made its final decisions
regarding the revised SO2 Primary NAAQS, as EPA described in
its notice of final rulemaking. See 75 FR at 35523. The Administrator
signed the final rule on June 2, 2010, and it was published in the
Federal Register on June 22, 2010. EPA's thorough and detailed
scientific rationale for the revised SO2 Primary NAAQS is
set forth at 75 FR 35524-35550. For the reasons discussed therein, and
taking into account information and assessments presented in the ISA
and the REA, as well as the advice and recommendations of CASAC, the
Administrator concluded that the then-current 24-hour and annual
primary SO2 NAAQS were not requisite to protect public
health with an adequate margin of safety. The Administrator also
reviewed each of the elements of the NAAQS--indicator, averaging time,
form, and level--and promulgated a revised standard of 75 ppb based on
the three-year average of the annual 99th percentile of the daily
maximum one-hour average concentrations of SO2. The
Administrator concluded that this standard will appropriately protect
public health with an adequate margin of safety, and specifically will
afford appropriate increased protection for asthmatics and other at-
risk populations against an array of adverse respiratory health effects
related to short-term (5 minutes to 24 hours) SO2 exposure.
These effects include decrements in lung function, increases in
respiratory symptoms, and related serious indicators of respiratory
morbidity including emergency department visits and hospital admissions
for respiratory causes. As the petitions for reconsideration do not
challenge EPA's scientific conclusions or any element of the new
standard, this response to the petitions does not further discuss the
Administrator's scientific determinations or her decision regarding the
final revised SO2 Primary NAAQS, other than to reiterate
that issues regarding how the standard would be implemented or the
costs of implementation received no consideration in the decision
regarding the NAAQS. See Whitman v. American Trucking Ass'ns, 531 U.S.
at 475-76.
2. Preamble Discussion of Anticipated Approaches for Implementation
    Although discussions regarding implementation are not part of the
NAAQS itself, it is EPA's customary practice to provide separate
implementation guidance--and in some cases regulatory requirements--
regarding a new or revised NAAQS, along with guidance on designations
and other issues. The December 8, 2009, NPRM for the SO2
Primary NAAQS included a summary discussion regarding future
implementation actions such as designations of areas under the
standard, SIP development, and new source review (NSR) and PSD
permitting. See 74 FR 64810, 64858-64. This discussion essentially
outlined the separate statutory provisions and requirements that would
be triggered following final promulgation of a revised NAAQS under
section 109(d). As part of this general discussion, EPA presented
limited preliminary explanations of how the Agency expected some of
these future actions might be addressed. For example, regarding area
designations under section 107(d) of the Act, EPA stated it did not
expect new monitors required under a new monitoring network would be in
place in time to generate data to inform designations under the
statutory timetable, and the Agency explained that some areas could be
designated as unclassifiable because EPA would be unable to determine
whether they are violating the 1-hour standard or contributing to a
violation in a nearby area. See 74 FR at 64859. EPA also summarized the
CAA section 110 requirement that States submit SIPs showing attainment
and maintenance of a revised NAAQS through control programs directed at
sources of SO2 emissions, including, for example, NSR and
PSD programs. See 74 FR at 64859-63. Regarding PSD, EPA specifically
discussed preliminary issues regarding the use of modeling to
demonstrate that emissions increases from new or modified sources will
not cause or contribute to a violation of the new NAAQS. See 74 FR at
64862. However, the NPRM did not contain any proposed regulatory
provisions regarding area designations under section 107, or regarding
SIP implementation under section 110 and related provisions, except as
discussed below.
    The NPRM also proposed regulatory amendments regarding the
monitoring network design, in order to better identify where short-
term, peak ground-level concentrations of SO2 may occur. See
74 FR at 64849-55. EPA proposed a two-pronged monitoring network
comprised of all source-oriented monitors, with requirements that the
network contain at least a specified number of monitors in the
following locations: (1) Monitors in urban areas where there is a
higher coincidence of population and emissions, utilizing a Population
Weighted Emissions Index (PWEI), and (2) monitors in States based on
each State's contributions to the national SO2 emissions
inventory. This two-pronged network would have resulted in a minimum of
approximately 348 source-oriented monitors nationwide. EPA noted that
due to multiple variables that affect ground-level SO2
concentrations caused by one or more stationary sources, it is
difficult to specify a priori a source-specific threshold, algorithm,
or metric by which to accurately identify the monitoring location where
peak concentrations occur. See 74 FR at 64850-51. Consequently, EPA
explained that States may need to conduct other quantitative analyses,
such as modeling, to identify where ground-level SO2 maximum
concentrations may occur and where to site monitors (see 74 FR at
64851-52, 64853-54), and requested comment on whether to utilize
existing screening and refined modeling tools to identify facilities
with the potential to cause an exceedance of the proposed revised
SO2 NAAQS (see 74 FR at 64854-55).
    Besides monitoring and reporting requirements, the only
implementation related regulatory provisions EPA proposed had to do
with making the transition to the new standard and including ``anti-
backsliding'' principles consistent with section 172(e) of the Act. See
74 FR at 64863-64. EPA announced it was proposing that the prior NAAQS
would remain in place for one year following the effective date of a
designation under the new NAAQS in an area, before being revoked in
most attainment areas. Further, EPA proposed that all existing SIP and
FIP requirements currently in effect under CAA sections 110, 191 and
192 would remain in effect. For all areas designated nonattainment
under the prior NAAQS or subject to ``SIP Calls,'' EPA proposed that
the prior NAAQS would remain in effect until the area had received full
approval of a SIP meeting the attainment requirements of the new NAAQS.
EPA proposed regulatory amendments to 40 CFR 50.4 to this effect. The
final NAAQS rulemaking promulgated these proposed requirements, with
minor clarifying amendments to address public comments received on the
proposed

requirements. See 75 FR at 35580-82; 40 CFR 50.4(e).
    The final rulemaking notice, in addition to explaining the codified
requirements regarding monitoring and anti-backsliding, also presented
a more thorough non-binding discussion than did the NPRM of how EPA
anticipated subsequent designations and SIP planning actions would be
implemented. See 75 FR at 35550-80. Partly in response to public
comments arguing that the proposed monitoring network was
simultaneously insufficient to identify all points of maximum ambient
SO2 concentrations and overly burdensome in the number of
monitors it proposed to require, EPA explained that it now expected to
follow its traditional approach in SO2 NAAQS implementation
of utilizing both modeling and monitoring to inform future designation
and SIP approval actions. EPA explained that its anticipated approach
would better address: (1) The unique source-specific impacts of
SO2 emissions, (2) the special challenges SO2
emissions present in terms of monitoring short-term SO2
levels for comparison with the NAAQS, (3) the generally superior
utility that modeling offers for assessing SO2
concentrations, and (4) the most appropriate method for ensuring that
areas attain and maintain the NAAQS, taking into account the potential
substantial SO2 emissions reductions from forthcoming
national and regional rules currently under development. See 75 FR at
35550. EPA explained that except for the final regulatory provisions
such as those regarding the promulgated monitoring network, the
implementation discussion explained the Agency's expected and intended
approach to future action as guidance, not as final agency action, and
acknowledged that EPA's approaches may continue to evolve as actual
implementation proceeds. Id. For example, in the part of the discussion
outlining EPA's general expectation for what roles modeling and
monitoring would play in initial area designations under CAA section
107, EPA noted that decisions about whether to base an attainment
designation on monitoring alone would be made on a case-by-case basis.
See 75 FR at 35552, n. 22. EPA further explained that it planned to
issue more implementation guidance, particularly regarding the use of
refined dispersion modeling. See 75 FR at 35550. EPA has in fact
already provided some further guidance regarding implementation of the
revised SO2 Primary NAAQS. See Memorandum from Stephen D.
Page, Director, Office of Air Quality Planning and Standards, to
Regional Air Division Directors, ``Guidance Concerning Implementation
of the 1-hour SO2 NAAQS for the Prevention of Significant
Deterioration Program,'' and attachments (Aug. 23, 2010) (included in
the docket for this notice of denial).
    EPA described its historical preference for having used modeling
more than monitoring to support SO2 NAAQS compliance
determinations, and referred to numerous prior actions dating from the
late 1970s through 2002 in implementing the SO2 NAAQS that
had taken this approach. See 75 FR at 35551. EPA explained the unique
aspects of SO2 that had caused the Agency to have less
confidence in relying on monitoring compared to situations involving
other NAAQS pollutants and how this affected its expected approach to
initial designations, given that the new monitoring network would not
be in place in time under the statutory timetable for issuing
designations. EPA also indicated that it did not expect States to be
able in that timeframe to conduct refined dispersion modeling for all
of the sources that may potentially cause or contribute to a violation
of the revised NAAQS. See 75 FR at 35551-52. EPA thus explained that it
was likely that most areas would therefore be initially designated as
``unclassifiable'' under the new NAAQS, and that an appropriate
approach needed to be identified to ensure that all areas ultimately
attain and maintain the revised NAAQS. See 75 FR at 35552-53. The
anticipated approach, EPA discussed, was to rely upon the CAA section
110(a)(1) requirement for SIP submissions from all areas--attainment,
unclassifiable, and nonattainment--following NAAQS revision. Although
EPA had often historically expected very little from States in this
submission in the way of substantive demonstrations or control
requirements, relying on new source review programs to keep areas in
attainment, EPA explained that in the case of SO2 the
section 110(a)(1) SIP provided an opportunity to allow States to
include in attainment demonstration modeling expected SO2
reductions from future federal and regional control programs currently
in development that would not be in effect in time to inform initial
designations. Id. To ensure that these attainment demonstrations would
result in timely nationwide attainment of the new NAAQS just as
expeditiously as would occur if EPA were to designate as nonattainment
areas with sources that may potentially cause or contribute to NAAQS
violations in advance of these new national and regional programs
becoming effective, EPA explained that it anticipated States would
submit section 110(a)(1) SIPs to show attainment on the same schedule
as would apply for nonattainment areas, i.e., no later than
approximately August 2017. EPA indicated its expectation that this date
would represent attainment as expeditiously as practicable for all
areas. Id. EPA provided detailed non-binding guidance discussions of
its expected approach toward future designations at 75 FR 35569-71, and
of its expected implementation strategy at 75 FR 35571-80. However, EPA
noted that any determination of actual attainment dates would await
notice and comment rulemaking with respect to a particular area and
SIP. Id. at 35573.
    Although the discussion regarding designations and SIP
implementation constituted non-binding guidance, the approach discussed
had a role in EPA's final decisions on the size of the required
monitoring network, and the anti-backsliding requirements. The
discussion had no impact on the Agency's final decision on the NAAQS
itself. In particular, partly as a result of EPA's review of its
historic practice in assessing SO2 NAAQS compliance, EPA in
the final rule modified its proposed requirements concerning the
minimum size of the monitoring network. See 75 FR at 35554, 35556-62.
The result was that EPA reduced the final minimum monitoring network
requirement to approximately 163 monitors from the proposed number of
approximately 348. See 75 FR at 35557. And, as mentioned above, within
the implementation discussion EPA discussed its promulgated
requirements addressing the ``anti-backsliding'' provisions of CAA
section 172(e). See 75 FR at 35580-82. Finally, both in order to
conform the regulatory text for the new NAAQS to that addressing other
NAAQS, and in recognition of the fact that both monitoring and modeling
may be used by States to implement the new NAAQS, EPA added clarifying
regulatory text to refer to those situations in which compliance is
measured by use of monitoring. See 75 FR at 35582; 40 CFR 50.17(b) and
section 1(a) of Appendix T to part 50.
3. Petitions for Reconsideration and for Judicial Review and Stay
Requests
    Following promulgation of the revised SO2 Primary NAAQS,
on August 23, 2010, numerous parties filed petitions for judicial
review in the U.S. Court of Appeals for the D.C. Circuit. See National
Environmental Development Association's Clean Air Project v. EPA,

No. 10-1252 (consolidated with Nos. 10-1254, 10-1255, 10-1256, 10-1258
and 10-1259) (D.C. Cir.). Each of those parties also on the same day
submitted to EPA petitions for administrative reconsideration of the
rule under CAA section 307(d)(7)(B). The petitions for reconsideration
objected to EPA's final rulemaking preamble discussion explaining the
Agency's anticipated approaches in future designations and SIP actions.
Some of the petitioners characterized their petitions as requesting,
first, ``clarification'' from EPA regarding ``key portions of the
implementation provisions of the Rule to ensure that the Rule is
implemented as written'' (see, e.g., UARG Petition at 3), and, second,
in the alternative, that EPA reconsider its discussed approach of how
it intends to implement the revised NAAQS and conduct notice and
comment on implementation procedures (see, e.g., id.). In addition,
each petition requested that EPA administratively stay the final rule's
effectiveness pending such reconsideration. Id.
    Specifically, EPA received: A single petition for reconsideration
from the Utility Air Regulatory Group (UARG), the America Petroleum
Institute (API), the Council of Industrial Boilers (CIBO), the American
Iron and Steel Institute (AISI), the American Coke and Coal Chemicals
Institute (ACCCI), the American Chemistry Council (ACC), the American
Forest & Paper Association (AF&PA), the American Wood Council (AWC),
the Brick Industry Association (BIA), the Corn Refiners Association
(CRA) and the National Oilseed Processors Association (NOPA)
(collectively, UARG); and separate petitions from the National
Environmental Development Association's Clean Air Project (NEDA/CAP),
ASARCO LLC (ASARCO), the Montana Sulphur & Chemical Company (MSCC), the
Texas Commission on Environmental Quality (TCEQ), and the States of
North Dakota and South Dakota (ND and SD). Additionally, EPA's Region 3
Office received a letter from the West Virginia Department of
Environmental Protection (WVDEP) objecting to the final rule and urging
EPA to ``reconsider'' its anticipated approach to implementation of the
NAAQS, and the Arkansas Department of Environmental Quality (ADEQ) sent
the Administrator a letter in support of the petitions submitted by
TCEQ and by North Dakota and South Dakota.
    Before EPA could respond to the petitions for reconsideration and
their requests for an administrative stay of the SO2 Primary
NAAQS, on October 8, 2010, the State of North Dakota filed in the D.C.
Circuit a motion (ND Motion) asking the Court to either stay the
effectiveness of the final SO2 Primary NAAQS pending
completion of judicial review of the rule, or, in the alternative, stay
the effectiveness of the June 2, 2011, statutory deadline for States to
submit any recommendations for attainment/nonattainment designations.
See ND Motion at 20. On November 8, 2010, UARG, NEDA/CAP, and the
SO2 NAAQS Coalition filed a response in support of the ND
Motion, as did TCEQ and ASARCO. On the same day, EPA filed its response
in opposition to the ND Motion, and so did the American Lung
Association (ALA) and the Environmental Defense Fund (EDF) as
intervenor-movants. Following this, on November 22, 2010, North Dakota
filed its reply to the various responses, and EPA filed a motion to
strike the responses filed by the UARG, NEDA/CAPS, the SO2
NAAQS Coalition and ASARCO. On December 2, 2010, these petitioners
filed their response to EPA's motion to strike, to which EPA replied on
December 10, 2010. On December 14, 2010, the Court issued an order
denying EPA's motion to strike, granting EPA's motion to hold the
litigation in abeyance, allowing EPA to file a response to the
responses in support of the ND Motion by January 18, 2011, directing
EPA to file a motion to govern further proceedings in the litigation by
January 18, 2011, and deferring a ruling on the ND Motion to stay the
rule pending further order of the Court.

II. Standard for Reconsideration

    Section 307(d)(7)(B) of the CAA strictly limits petitions for
reconsideration both in time and scope. It states that: ``Only an
objection to a rule or procedure which was raised with reasonable
specificity during the period for public comment (including any public
hearing) may be raised during judicial review. If the person raising an
objection can demonstrate to the Administrator that it was
impracticable to raise such objection within such time or if the
grounds for such objection arose after the period for public comment
(but within the time specified for judicial review) and if such
objection is of central relevance to the outcome of the rule, the
Administrator shall convene a proceeding for reconsideration of the
rule and provide the same procedural rights as would have been afforded
had the information been available at the time the rule was proposed.
If the Administrator refuses to convene such a proceeding, such person
may seek review of such refusal in the United States court of appeals
for the appropriate circuit (as provided in subsection (b)). Such
reconsideration shall not postpone the effectiveness of the rule. The
effectiveness of the rule may be stayed pending such reconsideration,
however, by the Administrator or the court for a period not to exceed
three months.''
    Thus, by the terms of CAA section 307(d)(7)(B), it is clear that
the right to seek reconsideration of a rule is afforded with respect to
decisions that are final rulemaking actions for which judicial review
may be obtained under CAA section 307(b)(1) and which have some final
effect that could potentially be stayed by either a court or by the
Administrator. EPA may not be required to reconsider non-final actions,
such as non-binding guidance discussions, for which judicial review is
not otherwise available and which do not themselves take effect at any
time. Moreover, the requirement to convene a proceeding to reconsider a
rule is based on the petitioner demonstrating to EPA both: (1) That it
was impracticable to raise the objection during the comment period, or
that the grounds for such objection arose after the comment period but
within the time specified for judicial review (i.e., within 60 days
after publication of the final rulemaking notice in the Federal
Register, see CAA section 307(b)(1)); and (2) that the objection is of
central relevance to the outcome of the rule.
    As to the first procedural criterion for reconsideration, a
petitioner must show why the issue could not have been presented during
the comment period, either because it was impracticable to raise the
issue during that time or because the grounds for the issue arose after
the period for public comment (but within 60 days of publication of the
final action). Thus, CAA section 307(d)(7)(B) does not provide a forum
to request EPA to reconsider issues that actually were raised, or could
have been raised, prior to promulgation of the final rule.
    In EPA's view, an objection is of central relevance to the outcome
of the rule only if it provides substantial support for the argument
that the promulgated regulation should be revised. See, e.g., EPA's
Denial of the Petitions to Reconsider the Endangerment and Cause or
Contribute Findings for Greenhouse Gases under Section 202 of the Clean
Air Act, 75 FR 49556, 49561 (Aug. 13, 2010). This interpretation is
appropriate in light of the criteria adopted by Congress in this and
other provisions in section 307(d). Section 307(d)(4)(B)(i) provides
that ``[a]ll documents which become available after the proposed rule
has been published and which the Administrator determines are of
central

relevance to the rulemaking shall be placed in the docket as soon as
possible after their availability.'' This provision draws a distinction
between comments and other information submitted during the comment
period, and other documents which become available after publication of
the proposed rule. The former are docketed irrespective of their
relevance or merit, while the latter must be docketed only if a higher
hurdle of central relevance to the rulemaking is met.
    Congress also used the phrase ``central relevance'' in sections
307(d)(7)(B) and (d)(8), and by reference in (d)(9)(D), and in each
case Congress set a more stringent hurdle than in section 307(d)(4).
Under section 307(d)(7)(B), the Administrator is required to reconsider
a rule only if the objection is ``of central relevance to the outcome
of the rule.'' Likewise, section 307(d)(8) authorizes a court to
invalidate a rule for procedural errors only if the errors were ``so
serious and related to matters of such central relevance to the rule
that there is a substantial likelihood that the rule would have been
substantially changed if such errors had not been made.'' Section
307(d)(9)(D) then applies both the section 307(d)(7)(B) and (d)(8)
requirements in limiting a court's ability to reverse an EPA final
action found to be without observance of procedure required by law. In
each of these provisions, it is not enough that the objection or error
be of central relevance to the issues involved in the rulemaking, as in
section 307(d)(4). Instead, the objection has to be of central
relevance ``to the outcome of the rule'' itself, and the procedural
error has to be of such central relevance that it presents a
``substantial likelihood that the rule would have been substantially
changed.'' Central relevance to the issues involved in the rulemaking
is not enough to meet the criteria Congress set under sections
307(d)(7)(B), (d)(8) or (d)(9)(D). These provisions all require that
the objection or error be central to the substantive final decision
that is the outcome of the rulemaking and that is taking effect. This
difference is significant, and indicates that Congress set a much
higher hurdle for disturbing a final rule that has already been issued,
as compared to the less stringent criteria for docketing of documents
before a decision has been made and a rule has been issued.
    In this context, EPA's interpretation of section 307(d)(7)(B) gives
full and appropriate meaning to the criteria adopted by Congress. An
objection is considered of central relevance to the outcome of the rule
only if it provides substantial support for the argument that the final
promulgated regulation should be revised. This properly links the
criteria to the promulgated outcome of the rulemaking, not just to the
issues addressed in the rulemaking which may or may not have influenced
that final action taken by EPA. It requires that the objection be of
such substance and merit that it can be considered central to the final
outcome of the rulemaking. This interpretation is consistent with
section 307(d)(8), which also ties central relevance to the outcome of
the rulemaking, in terms of a ``substantial likelihood'' that the
promulgated rule would be ``substantially changed,'' and with section
307(d)(9)(D), which assumes that the objection regard an ``action''
that a court ``may reverse'' and for which a ``procedure required by
law'' exists. This interpretation gives proper weight to the approach
throughout sections 307(b) and (d) of the importance Congress
attributed to preserving the finality of agency rulemaking decisions,
once they have in fact been made. This interpretation is also
consistent with the case law, as discussed below.
    As discussed in this decision, EPA is denying the petitions because
they fail to meet these criteria. At the outset, the objections raised
in the petitions to reconsider all regard non-final, non-binding
guidance discussion that is not final rulemaking action that is ripe
for either judicial review or for reconsideration. Additionally, in all
cases the objections are not of central relevance to the outcome of the
rule because they do not provide substantial support for the argument
that the final SO2 Primary NAAQS should be revised.
Moreover, the objections raised in the petitions regard issues that
were or could have been raised during the comment period of the NPRM.
Parts III-V of this decision explain why EPA is denying the petitions
with respect to the objections set forth in these petitions for
reconsideration. For some of these issues, the petitioners have not met
the procedural predicate for reconsideration. That is, the petitioners
have not demonstrated that it was impracticable to raise these
objections during the comment period, or that the grounds for these
objections arose after the close of the comment period but within 60
days after publication of the final rule. As such, they do not meet the
statutory criteria for administrative reconsideration under CAA section
307(d)(7)(B). For all of the objections, the petitioners' objections
and argument in terms of substance are not ``of central relevance'' to
the outcome of the promulgated rulemaking establishing the revised
NAAQS. Moreover, the objections regard discussion in the preamble that
is not final action at all, and therefore EPA concludes that the non-
binding discussion cannot arguably be considered either of central
relevance to the promulgated SO2 NAAQS or something that EPA
was required to provide pursuant to section 307(d)'s procedural
requirements. Thus, none of the objections meet the criteria for
reconsideration under the CAA.
    EPA also rejects TCEQ's claim that EPA should reconsider the final
rule under section 557 of the Administrative Procedure Act (APA), even
if the criteria for reconsideration under CAA section 307(d)(7)(B) are
not met (TCEQ at 4). First, CAA section 307(d)(1) provides that APA
sections 553 through 557 do not, except as expressly provided in
section 307(d), apply to actions to which CAA section 307(d) applies,
such as promulgation of a NAAQS (see CAA section 307(d)(1)(A)). Second,
by its own terms APA section 557 applies only when a hearing is
required to be conducted under APA section 556, which in turn applies
only to hearings required under APA sections 553 or 554. See APA
sections 557(a), 556(a). Since those provisions do not apply to actions
promulgated under CAA section 307(d), APA section 557 is inapplicable.
    As mentioned above, EPA also received requests to administratively
stay the final revised SO2 Primary NAAQS as part of the
petitions for reconsiderations. Petitioners either tied their requests
for an administrative stay to their petitions for reconsideration under
CAA section 307(d)(7)(B), referred to EPA's general authority to
prescribe such regulations as are necessary to carry out EPA's
functions under CAA section 301(a), did not refer to any specific
statutory authority for granting an administrative stay, or filed the
stay request under section 705 of the Administrative Procedure Act, 5
U.S.C. 705. As described below, EPA is denying the petitions to
reconsider; hence there is no basis for issuance of a stay under CAA
section 307(d)(7)(B). Nor is it necessary for EPA to grant a stay by
rulemaking under authority of CAA section 301(a) to carry out the
Agency's functions in denying the petitions for reconsideration. APA
section 705 authorizes an agency to postpone the effective date of an
agency action pending judicial review when the agency finds that
justice so requires. In this case, the revised SO2 Primary
NAAQS was effective as of August 23, 2010. TCEQ's request for an
administrative stay relying upon APA section 705 was submitted by
petition on the same day that the SO2 Primary

NAAQS became effective. Even if EPA believed that an administrative
stay was warranted, which it does not, it is not clear whether EPA
would have authority under APA section 705 to stay an agency action
that has already gone into effect. Postponing an effective date implies
action before the effective date arrives.
    In any case, an administrative stay of the final SO2
Primary NAAQS is not warranted. As explained in Part VI below, in
response to the arguments raised by petitioners, (1) the petitioners
have not made a strong showing on the merits, for all of the reasons
upon which EPA is denying the petitions to reconsider; (2) the
petitioners' arguments concerning irreparable harm fail to adequately
account for the fact that no final actions implementing the approaches
discussed in the preamble have yet been taken under the revised NAAQS;
(3) the petitioners' arguments do not consider the possibility of harm
to other parties if a stay of the NAAQS were to be granted; and (4)
granting a stay would be contrary to the public interest.

III. Administrative Process Issues

A. Summary of Petitioners' Arguments

    Petitioners' procedural objections come in several forms, with most
petitioners raising them repeatedly. The central assumption of each
objection is that EPA's final NAAQS rulemaking took final action on the
discussed implementation approaches, and that the discussion and
approaches are of central relevance to the outcome of the final revised
SO2 Primary NAAQS. Further, petitioners often assert that
but for the inclusion of the discussion of implementation approaches,
which was allegedly done in a procedurally flawed manner, EPA would
have promulgated a different revision of the SO2 Primary
NAAQS. They claim that notice and comment rulemaking is required for
the implementation ``aspect'' of the final NAAQS, and rely upon the
premise that the final preamble discussion constitutes final agency
action on such an allegedly required aspect.
    Several petitioners argued that EPA gave no indication in the NPRM
that the Agency might ``reduce the role of monitoring'' in NAAQS
attainment designations or that modeling might play a greater role in
SO2 NAAQS implementation, or that the requirements of CAA
section 110(a)(1) might be interpreted or implemented differently than
in the past. See UARG at 13-14, 22-25; NEDA/CAP at 3-4; ASARCO at 2-4,
4-6, 6-8, 8-10; MSCC at 1-2, 3-6, 6-9; TCEQ at 4, 11-14; ND and SD at
7-8, 8-9; WVDEP at 1, 2; ADEQ at 1. Consequently, the petitioners claim
the final preamble's implementation discussion deviates too sharply
from the NPRM to ``logically follow'' from the proposal without first
undergoing notice and comment procedures, as petitioners claim is
required by Small Refiner Lead Phase-Down Task Force v. EPA, 705 F.2d
506, 547 (D.C. Cir. 1983), and related cases. Presenting the
implementation discussion in response to limited comments, petitioners
argue, does not satisfy the claimed requirement to subject such a
discussion to notice and comment proceedings, and EPA's alleged
procedural error was so severe that there is a substantial likelihood
that the final NAAQS would have been changed if the error had not been
made, resulting in EPA's revised NAAQS not having been adequately
justified. See UARG at 22-25; NEDA/CAP at 3-4; ASARCO at 2-8; MSCC at
1-2, 3-6, 6-9; TCEQ at 4, 11-14; ND and SD at 8-9; WVDEP at 1, 2; ADEQ
at 1.
    The petitioners argue that reconsideration is warranted because
their objections regarding the implementation discussion ``are based on
actions'' EPA took in the final rulemaking and ``are of central
relevance to the outcome'' of the NAAQS rulemaking. As such,
petitioners claim, the public must be given an opportunity to comment
not just on the regulatory provisions of the NAAQS itself but also on
any intended implementation approach and possible methods for
determining compliance. See UARG at 17-19; NEDA/CAP at 3-4; ASARCO at
4-6; MSCC at 1-2; TCEQ at 11-14; ND and SD at 7-8. Moreover,
petitioners argue, EPA's stated intention in the final rulemaking
preamble to provide an opportunity for public comment on additional
guidance cannot ``cure'' the alleged procedural defect of not having
provided an opportunity to comment on the changed approach to
implementation of the NAAQS, especially where such guidance would not
be promulgated according to the CAA's required procedures for
rulemaking. See UARG at 27-28; NEDA/CAP at 3-4; ASARCO at 8-10.
    Below, EPA summarizes each of the petitioners' separate arguments
regarding procedural objections. While the petitioners' arguments are
thematically similar, they are structured differently, and do not each
raise the same points. Our responses, however, do not separately
address each petition, but rather provide our answers to the various
objections the petitioners raise.
1. UARG
    UARG claims that the NPRM included nothing in either its preamble
discussion or proposed regulatory text indicating that EPA intended to
reduce the emphasis on monitoring in issuing designations or to enhance
the emphasis on modeling compared to implementation in the past, and
that nothing in the NPRM suggested EPA would discuss a new approach
toward section 110(a)(1). UARG at 13. UARG points out that multiple
petitioners filed comments on the NPRM addressing the proposed level of
the NAAQS and the proposed revised design of the SO2
monitoring network and other implementation aspects, but did not
provide comments on any ``changes to the way EPA had historically
expected States to make their section 107(d) designations.'' Id. at 13-
14, fns. 29-33. UARG then claims that reconsideration is appropriate
under CAA section 307(d)(7)(B) because its objections are based on
actions EPA took for the first time in the final SO2 NAAQS
rulemaking and thus petitioners could not have raised them during the
comment period, that UARG's objections arose following promulgation of
the rule and during the period for judicial review, and that the
objections are of central relevance to the outcome of the rulemaking.
Id. at 17. UARG claims petitioners did not object to EPA's discussed
implementation approach focusing on modeling because EPA did not
discuss it in the NPRM, thus depriving interested parties of any
meaningful opportunity to comment on all aspects of the proposed
revised NAAQS, including its implementation. Id. at 18. Because EPA had
not previously, according to UARG, implemented the SO2 NAAQS
based primarily on the use of modeling and because the discussion
cannot in UARG's view be considered a logical outgrowth of the NPRM,
petitioners have not had a meaningful opportunity to comment. Id.
    UARG's central claim is that the public must be given an
opportunity to comment on ``all aspects'' of a NAAQS, not only its
numerical level but also the approaches EPA may use to implement it.
Id. Therefore, UARG asserts, EPA cannot make ``substantial changes in
methods being used to implement'' a NAAQS without notice and a hearing.
Id., citing Donner Hanna Coke Corp. v. Costle, 464 F.Supp. 1295, 1305
(W.D. N.Y. 1979). UARG claims that EPA may ``require the use of a
certain method'' to determine compliance with the SO2 NAAQS
only if EPA provides notice of such, citing Wisc. Elec. Power Co. v.

Costle, 715 F.2d 323, 326 (7th Cir. 1983) in which the court explained
that EPA could require monitored data of SO2 concentrations
to be reported in running averages, rather than block averages, if EPA
provides adequate notice. Id. at 18-19. If EPA does not provide notice
of an emission standard's implementation procedure, UARG claims, the
court will remand to EPA to allow for public comment on the rule. Id.
    UARG's objections also rely upon its premises that EPA has not
previously favored or required dispersion modeling to support
SO2 NAAQS compliance determinations, particularly in initial
designations under CAA section 107(d), and that EPA is now interpreting
CAA section 110(a)(1) ``to require'' that States include in SIPs
submitted under that provision modeled demonstrations of NAAQS
attainment and maintenance. Id. at 19-21. UARG disputes EPA's cited
examples as showing that the Agency has long utilized modeling in
SO2 NAAQS implementation, stressing its view that in the new
SO2 NAAQS EPA has now ``required States to support their
initial designation recommendations with modeling data alone or with
both monitoring and modeling data.'' Id. at 19-20. Instead, UARG
claims, EPA has historically expressed a preference of reliance on
monitoring data, and cites in support of this claim EPA's February 1994
``SO2 Guideline Document,'' EPA-452/R-94-008; a Letter from
Barber, Walter C., OAQPS, to Pickard, Ralph C., Indiana Air Pollution
Control Board (Sept. 3, 1981), and EPA's recent rulemakings for the
Lead NAAQS and NO2 NAAQS, 73 FR 66964 (Nov. 12, 2008) and 75
FR 6474 (Mar. 24, 2010), respectively. Id. at 20-21.
    In arguing that the final SO2 NAAQS is not a logical
outgrowth of the NPRM, UARG focuses on the proposed revised monitoring
requirements and absence of proposed requirements regarding modeling,
and again claims that the final rule ``would now require'' States to
conduct modeling for initial designations. Id. at 22. UARG claims that
the final rule ``does not adopt the monitoring approach that was
discussed'' in the NPRM, and that EPA ``is adopting'' a different
modeling-based approach. Id. This alleged change is too radical a
departure from the NPRM to satisfy the Small Refiner test, UARG claims,
as commenters could not have anticipated that EPA ``would adopt'' a
modeling approach ``in'' the final NAAQS nor that EPA would ``change''
how it ``is implementing'' CAA section 1109(a)(1). Id. at 22-23. Thus,
asserts UARG, granting reconsideration ``and conducting rulemaking on a
modeling-based SO2 NAAQS implementation approach'' would
provide the first opportunity for the public to comment and persuade
EPA to ``change the Rule.'' Id. at 23. EPA itself must provide this
opportunity to comment, UARG claims, and may not rely upon
``bootstrapping'' from comments regarding a modeling implementation
approach to satisfy its burden. Id. at 23-24. UARG further claims that
it would have submitted extensive comments on this approach that could
have changed the final NAAQS, based on UARG's view that the
conservatism of modeling approaches somehow has the effect of making
the NAAQS more stringent than its numerical level. Id. at 24-25. EPA's
stated intention to provide further guidance, including an opportunity
to comment on this guidance, is not an adequate substitute for
conducting ``full notice and comment rulemaking before changing the
final rule'' which allegedly ``now requires'' States to use modeling.
Id. at 28-29.
2. NEDA/CAP
    NEDA/CAP likewise claims that EPA committed procedural violations
in the final NAAQS rule because the NPRM ``provided that initial
SO2 designations were based on monitoring,'' whereas EPA
allegedly concedes that its ``final action'' reflects a change from the
proposed approach. NEDA/CAP at 1-2. NEDA/CAP claims EPA never provided
a meaningful opportunity to comment on this ``major change to the NAAQS
implementation process,'' and that NEDA/CAP would provide ``extensive
information'' on this issue if EPA grants reconsideration. Id. at 3.
Like UARG, NEDA/CAP asserts that its objections, per CAA section
307(d)(7)(B), are based on actions EPA took for the first time in the
final rule, could not have been raised during the public comment period
on the NPRM, arose following promulgation of the final rule and during
the period for judicial review, and are of central relevance to the
outcome of the rulemaking. Id. at 4.
    Also like UARG, NEDA/CAP claims that the public must be afforded a
chance to comment on ``all aspects of proposed revisions to NAAQS,
including the method of implementation,'' and that since EPA has
allegedly ``not previously utilized a modeling approach to
implementation'' the final preamble discussion of such an approach
``mandating the use of modeling, instead of monitoring, in the initial
implementation of the designation process is therefore a substantial
departure from the proposal'' and cannot be considered a logical
outgrowth of the proposal. Id. NEDA/CAP further claims that the NPRM
did not meet the requirement of CAA section 307(d)(3) to provide
notice, a ``critical legal issue regarding the requirement in the final
rule for States to use modeling.'' Id. at 4-5. Therefore, NEDA/CAP
argues, the public did not receive the proper legal notice that EPA
``might take away'' State discretion in recommending area designations,
and the public was deprived of its right to comment on this issue. Id.
at 5, citing Appalachian Power v. EPA, 135 F.3d 791, 816 (D.C. Cir.
1998) for the proposition that a final rule is a logical outgrowth only
if commenters ``clearly understood'' that a matter was under
consideration.
3. ASARCO
    ASARCO also alleges that the NPRM violated CAA section 307(d)(3) in
not providing the public an opportunity to comment on the final rule
preamble's discussion of the anticipated implementation approach.
ASARCO at 2. ASARCO also claims that a subsequent opportunity to
comment on future guidance ``cannot cure the violation.'' Id. In
addition to supporting UARG's arguments, ASARCO stresses that the
NPRM's discussion of modeling was limited to how it could be used to
identify where monitors should be placed within the proposed network
that would have employed 348 monitors. Id. at 2-3. ASARCO claims EPA
gave no notice of its position stated in the final preamble that
modeling is a technically appropriate, efficient and readily available
method to assess short-term ambient SO2 concentrations, and
disputes EPA's explanation that the Agency has long preferred modeling
over monitoring in SO2 implementation. Id. at 3-4. Thus,
ASARCO asserts, it was impracticable for commenters to address EPA's
``final determination to move toward a `hybrid' approach.'' Id. at 4.
    ASARCO then claims that the discussed ``hybrid'' approach played a
``central role in EPA's final determinations'' for implementation of
the new NAAQS, such as how monitors in the scaled-back network design
would be used. Id. It also ``changed'' how areas would be designated
under the NAAQS, with areas with monitors showing no violations being
designated as unclassifiable, ASARCO claims. Id. at 5. And such
unclassifiable areas will have more ``onerous requirements'' than were
described in the NPRM. Id. at 5-6. That EPA ``will also require''
modeling in SIPs demonstrating attainment is of ``vital importance'' to
the stringency of the NAAQS, ASARCO claims, and thus is ``of central
relevance to the outcome of the Final Rule'' such

that the public should have had an opportunity to comment on it,
particularly since it ``is a departure from how EPA has generally
implemented NAAQS'' according to ASACO. Id. at 6.
    EPA's discussion in the final rule violates CAA sections 307(d)(3),
(4) and (5), ASARCO claims, and cannot be supported as a response to
public comments, none of which asked EPA to ``shift the focus'' from
monitoring to modeling in showing NAAQS attainment, ASARCO claims. Id.
at 6-7. ASARCO cites several cases for the proposition that such a
response to comments is not adequate to meet the initial notice and
comment requirements of the CAA. Id. at 7, citing, e.g., McLouth Steel
Products Corp. v. Thomas, 838 F.2d 1317, 1323 (D.C. Cir. 1988). ASARCO
dismisses EPA's observation that the discussed anticipated approach
would address commenters' complaints that the proposed monitoring
network was too burdensome, and asserts that that burden would only be
replaced by more burdensome modeling, which according to ASARCO
prevents the discussion from being a logical outgrowth of the proposal.
Id. at 7-8. Since EPA was required to have provided an opportunity to
comment on the hybrid approach in the NPRM, ASARCO argues, the
``promise of an opportunity to comment on guidance in the future,'' at
which point EPA ``will not likely abandon the modeling requirement''
ASARCO claims the final rule imposed, is insufficient. Id. at 8-9.
This, AASARCO claims, runs afoul of cases such as Grand Canyon Air Tour
Coal. v. FAA, 154 F.3d 455, 468 (D.C. Cir. 1998) (``agency's mind must
be open to considering'' comments) and McLouth (the curative effect of
later notice ``depends upon the agency's mind remaining open enough at
the later stage''). Id. at 9. Thus, EPA is constrained by Kennecott
Corp. v. EPA, 684 F.2d 1007, 1019 (D.C. Cir. 1982) and PPG Indus., Inc.
v. Costle, 659 F.2d 1239, 1250 (D.C. Cir. 1981), which rejected
subsequent reconsideration as a cure for an initial procedural
violation. Id.
    ASARCO then asserts that subsequent modeling guidance cannot cure
the alleged procedural error, under Appalachian Power Co. v. EPA, 208
F.3d 1015, 1024 (D.C. Cir. 2000), because EPA notes that a purpose of a
monitoring data interpretation rule for a NAAQS is to give effect to
the form, level, averaging time and indicator specified in the
regulatory text, resolving in advance ambiguities that might occur
regarding use of monitoring data. Id. at 9-10. ASARCO asserts that
since the promulgated regulation addressing monitoring applies only to
situations where monitoring is used, ``the same holds true'' for
reliance on modeling, which could render EPA's specificity regarding
monitoring ``essentially meaningless without further direction on the
use of modeling.'' Id. at 10. Finally, ASARCO claims that a notice and
comment opportunity on implementation approaches must be provided since
the approach allegedly ``may affect the stringency of the standard,''
as ASARCO in fact commented on the NPRM that current modeling is
conservative and that there is a discrepancy between modeling and
monitoring data. Id. at 11, citing Asarco Comments at 12 (EPA-HQ-OAR-
2007-0352-0963.1) and UARG Comments at 32 (EPA-HQ-OAR-2007-0352-
0967.1). EPA did not explain how modeling will be used to meet
requirements for demonstrating NAAQS attainment, such as CAA section
107(d)(3)(E)(i) and (iii), ASARCO claims, or why modeling provides
accurate or reliable information to reflect NAAQS compliance, and the
failure to give the public notice of EPA's ``decision'' to use modeling
in the NPRM did not give the public sufficient information to
understand the full implications of the revised NAAQS, ASARCO claims.
Id. at 11-12.
4. MSCC
    MSCC claims that the grounds for its objections to the
SO2 Primary NAAQS arose after the public comment period,
that its objections were impracticable to raise during the comment
period, and that the objections are of central relevance to the outcome
of the rule. MSCC at 1. Therefore, MSCC claims, the ``final rules'' are
not a logical outgrowth of the ``proposed rules,'' and EPA failed to
provide an adequate opportunity for notice and comment. Id. at 2. MSCC
objects to EPA's not having specifically, in the NPRM, asked for public
comments on using monitoring and modeling in a combined ``hybrid''
manner to assess NAAQS compliance, or on whether to use modeling for
larger sources and monitoring for smaller sources and those not
conducive to modeling. Id.
    Citing Small Refiner and related cases, MSCC argues that the test
for whether a final rule is a logical outgrowth of its proposal is
whether commenters should have anticipated whether a final requirement
might be imposed, and were fairly apprised of the subjects and issues
of the rulemaking. Id. at 3. MSCC analyzes the Small Refiner Court's
differing treatment of final actions that were taken in response to
numerous comments, and in response to a single comment. Id. at 4; see
also Small Refiner at 546-549. MSCC argues that since no single
commenter on the SO2 NAAQS recommended EPA's discussed
``hybrid'' modeling and monitoring approach to implementation, and
since the NPRM made no mention of such an approach, EPA's discussion
cannot be a logical outgrowth. MSCC at 5. MSCC asserts that EPA ``(1)
focused its proposal entirely on changes to the existing monitoring
network, (2) proposed no changes to modeling requirements, and (3) did
not mention the word `hybrid' even once.'' Id. (emphasis removed). That
makes the connection between the NPRM and the final preamble discussion
too tenuous, MSCC claims. Id.
    Moreover, MSCC argues, the final rule's preamble discussion
deviates too sharply from the proposal for interested parties to have
been afforded an opportunity to comment on it. Id. at 6. Thus, MSCC
claims EPA failed to serve the purposes of public notice, namely to
ensure the regulation will be tested by exposure to diverse public
comment, provide fairness to affected parties, and enhance the quality
of judicial review. Id. Citing numerous instances in the NPRM
discussing the proposed changes to monitoring as a means of assessing
NAAQS compliance, and contrasting those to instances in the final
preamble discussing a hybrid modeling and monitoring approach, which
MSCC conceded EPA discussed partly in response to comments claiming
that the proposed monitoring approach ``was not a desirable one,'' MSCC
argues that the basic difference between the two approaches reflects
impermissible procedural error. Id. at 7-8. MSCC argues that in not
having first discussed a hybrid approach in the proposal it is not
clear whether EPA would have discussed it in the same way in the final
preamble. Id. at 8-9.
5. TCEQ
    TCEQ asserts that in the final SO2 NAAQS EPA
``determined that dispersion modeling would be required to determine
attainment'' with the NAAQS in designations and re-designations,
without having provided for public comment ``on the impact of this
decision on the form of'' the NAAQS or on whether modeling is
permissible under the CAA. TCEQ at 3. Like the other petitioners, TCEQ
claims that this means the objections to the discussion arose after the
public comment period and are of central relevance to the outcome of
the rule, triggering the duty to reconsider it

under CAA section 307(d)(7)(B). Id. at 4-5. TCEQ also claims EPA has
authority to reconsider the rule under APA section 557, even if CAA
section 307(d)(7)(B) does not require reconsideration. Id. at 4. TCEQ
claims that its three primary objections, (1) that the hybrid modeling-
monitoring discussion results in an inappropriate form of the NAAQS,
(2) that EPA's ``interpretation'' does not adhere to the regulatory
text of 40 CFR 50.17(b), and (3) that a hybrid approach would be a
``divergence from CAA section 110(a)(1) and (2) attainment and
maintenance requirements for all areas, whether designated as
nonattainment or not,'' are of central relevance to the ``final
SO2 rule and its eventual implementation by states.'' Id. at
5.
    TCEQ argues that EPA's introduction of the use of modeling in
SO2 NAAQS implementation in the final preamble, as opposed
to the NPRM, led TCEQ to limits it comments on the ``form'' of the
NAAQS without consideration of issues such as whether EPA's existing
modeling guidelines and procedures would apply regarding elements such
as evaluation of background sources and the integration of predicted
concentrations with monitoring data. Id. at 6. TCEQ asserts that
difficulties with integrating modeling and monitoring data that it
claims have arisen regarding other pollutants will apply to
SO2, and that EPA gave ``no reason for TCEQ to expect that
EPA would adopt a form of the SO2 standard with similar
problems, without an opportunity to comment.'' Id. at 7.
    TCEQ also argues that amendments to proposed regulatory text were
made without proposal for comment, such as adding the phrase ``at an
ambient monitoring site'' to the 40 CFR 50.17(b) and (c) and Appendix T
section 1 (a) provisions addressing monitoring. Id. at 9. TCEQ observes
that the explanatory preamble language regarding these monitoring
provisions' amendments, in which EPA noted that ``[t]his text does not
restrict or otherwise address approaches which EPA or States may use to
implement the new 1-hour NAAQS, which may include, for example, use of
modeling'' (see 75 FR at 35582), ``was never proposed for comment,''
and claims that it reflects an interpretation that conflicts with the
regulatory text and is not within EPA's discretion. Id. at 9-10. TCEQ
claims it had no notice that the regulatory text could be so amended,
nor that EPA ``intended to interpret this rule language in a manner
inconsistent with its plain meaning, and thus could not have commented
on this issue during proposal.'' Id. at 10.
    TCEQ also claims that as a result of the final preamble discussion
unclassifiable areas ``will now be required to submit maintenance
plans, to show maintenance and attainment of the NAAQS, containing
elements that were not clearly discussed in the proposed rule.'' Id. at
10-11. TCEQ asserts it ``could not have foreseen that EPA would change
its admitted historical interpretation of the maintenance requirement
upon adoption of the final SO2 NAAQS, and thus could not
have commented on this change.'' Id. at 11. TCEQ also claims that EPA's
discussion of the use of modeling ``could not have been anticipated by
Texas or other stakeholders given that the use of modeling to
determin[e] nonattainment areas was'' in TCEQ's view removed in the
1990 CAA Amendments. Id. at 12-13.
    Consequently, TCEQ argues, the final rule is not a logical
outgrowth of the NPRM, and is like a rule struck down in National
Mining Ass'n v. Mine Safety and Health Admin., 116 F.3d 520, 531 (D.C.
Cir. 1997), where the agency's rule changed longstanding practice after
issuing a proposal that would have left that aspect of the rules
unchanged. MSCC at 13-14. TCEQ further argues that the SO2
NAAQS is analogous to the situation in Environmental Integrity Project
v. EPA, 425 F.3d 992, 998 (D.C. Cir. 2005), stating that a logical
outgrowth may not include an agency decision to repudiate its proposed
interpretation and adopt its inverse. MSCC at 14.
6. North Dakota and South Dakota
    ND and SD object to EPA's not having publicly discussed ``its
intention to have states use modeling data over monitoring data'' until
the final preamble. ND and SD at 2. After presenting their substantive
objections to EPA's preamble discussion (id. at 2-7), ND and SD claim
they did not have an opportunity to raise them during the comment
period because the NPRM did not discuss the use of modeling, and that
their objections are of central relevance to the final rule. Id. at 7.
Thus, ND and SD argue, EPA must reconsider the final rule and provide
an opportunity to comment, in order to cure the NPRM's alleged failure
to satisfy the CAA section 307(d)(3) requirement to provide an adequate
opportunity to comment on the proposal. Id. at 7-8. ND and SD assert
that the final rule departs too sharply from the proposal to satisfy
the Small Refiner test for a logical outgrowth, and that EPA's final
rule preamble discussion cannot be supported as a response to comments
received from the public. Id. at 8-9.
7. WVDEP
    Although not submitted as a formal petition for reconsideration
under CAA section 307(d)(7)(B), WVDEP communicated with EPA Region 3 by
a letter entitled ``Objection to Final SO2 NAAQS Rule [75 FR
35520; Docket No. EPA-HQ-OAR-2007-0352]'' to raise objections very
similar to those presented in the actual petitions. WVDEP claims that
the ``final rule contains a number of significant changes from the
proposed rule, which warrant supplemental rule-making.'' WVDEP at 1.
Therefore, WVDEP urges EPA to ``reconsider its intended approach,'' and
asserts that EPA ``should conduct supplemental rule-making and offer
proper opportunity for public review and comment of significant changes
from the proposed rule.'' Id. at 2.
8. ADEQ
    Similarly, ADEQ did not submit its own formal petition for
reconsideration under CAA section 307(d)(7)(B), but sent a letter to
EPA in support of TCEQ's and ND and SD's petitions. ADEQ asserted EPA
had failed to properly conduct notice and comment rulemaking
``regarding a significant departure from the monitoring approach set
forth in the proposed rule,'' thus denying ADEQ the opportunity to
comment.'' ADEQ at 1.

B. Responses to the Claims and Arguments Raised by the Petitioners

    EPA presents its responses to the petitioners' procedural
objections below in a collective format, rather than on a petitioner-
by-petitioner basis, since the objections to a great extent are
identical, incorporate other petitioners' arguments, or repeat similar
arguments. Where necessary and appropriate, EPA responds to specific
claims raised by individual petitioners within our broader responses.
1. Petitioners Object to Agency Action Which Is Not Final
    Petitioners' claims, arguments and the information they submit do
not undermine or lead us to change our scientific and other conclusions
regarding what SO2 Primary NAAQS is requisite to protect
public health with an adequate margin of safety, as determined under
section 109 of the CAA. Nor do they change or undermine our conclusions
regarding the promulgated requirements for an SO2 monitoring
network centered on areas where there is an increased coincidence

of population and SO2 emissions. The petitions do not change
EPA's final decisions regarding the need to revise the prior
SO2 Primary NAAQS, and what those revisions should be. The
petitioners' arguments are not based on consideration of the body of
scientific information that informed EPA's final decisions in
promulgating the revised SO2 Primary NAAQS. In fact,
petitioners' arguments have nothing to do with EPA's scientific
conclusions, and provide no new information or basis for EPA to revisit
those conclusions or the specific SO2 Primary NAAQS that EPA
promulgated.
    Instead, petitioners' arguments rely on an apparent assumption that
EPA's non-binding preamble discussion of anticipated approaches for
separate future implementation actions constituted, itself, final
agency action that governs those future actions now and imposes
immediate binding requirements to implement the NAAQS in a certain way.
Although petitioners do not demonstrate how EPA's discussion has such
final, binding and enforceable effect, their requests that EPA
reconsider the final rule necessarily relies upon their implicit
assumption that EPA has already taken final rulemaking action on the
discussed implementation approaches. Only if EPA had taken such final
action on these discussed approaches could there be an issue regarding
whether EPA's discussion was a ``logical outgrowth'' of the proposed
rule, and whether it was of ``central relevance'' to the actually
promulgated revised SO2 Primary NAAQS.
    Similarly, for EPA's discussion to constitute a ``procedural
error,'' it would first have to have been an actual ``determination''
that is a final action, but it is not. EPA plainly stated that the
discussion represented non-binding guidance regarding future expected
actions, that EPA's anticipated approach could continue to evolve as
further expected guidance is developed, and that EPA expected there to
be circumstances in which the anticipated approaches may not apply. See
75 FR at 35552, n.22. In other words, regarding the implementation
discussion, EPA has not yet even taken a final action that could be
presently ``reconsidered'' under CAA section 307(d)(7)(B). Instead, any
interested party may raise its objections to EPA's future use of an
approach like that presented in the preamble discussion (should that
ever occur) in a specific action that applies it, such as a designation
action under CAA section 107(d)(1) or a SIP approval action under
section 110.
    As the preamble makes clear, EPA has not taken any final action or
promulgated any regulatory requirements regarding either designations
under CAA section 107(d) or SIPs under CAA section 110(a)(1), and, in
particular, has taken no final action on its approach to making
attainment determinations. To the contrary, the preamble specifically
preserves EPA's ability to make those decisions solely on the basis of
monitoring data. See 75 FR at 35552, n.22. Nothing in the final
promulgated rule prevents a State, for example, from basing its
designation recommendation on monitoring data. EPA did not promulgate
or revise any requirements regarding the use of modeling in the final
SO2 NAAQS. Because the preamble discussion regarding
implementation is not final agency rulemaking action, it is not
appropriate for reconsideration under CAA section 307(d)(7)(B).
    In the preamble to the final rule, EPA explained that the Agency
anticipated that in subsequent actions it would continue its historic
practice of relying on both modeling and monitoring for determining
whether an area is in attainment with the SO2 NAAQS, and
adopted rules for a smaller monitoring network than EPA initially
proposed. See 75 FR at 35550-51. But the preamble makes clear that,
except for the promulgated requirements relating to the scope of the
monitoring network and the new Federal Reference Method, EPA is still
developing its policy for such future actions as designations and SIP
approvals, and intends to issue further guidance in the future through
a notice-and-comment process. Id. And, as noted above, the preamble
also states EPA's expectation that any decisions about whether to base
an attainment designation or determination on monitoring alone, without
reliance on modeling, would similarly be made on a case-by-case basis
through rulemaking. Id. at 35552 n.22.
    The procedural objections boil down to a claim that the preamble of
the final rule requires the use of air quality modeling for determining
whether an area is in attainment with the revised SO2 NAAQS,
that this approach differs from the approach discussed in the preamble
to the proposal, and that the public did not have an opportunity to
comment on the approach discussed in the final rule. This claim lacks
merit for two reasons.
    First, in objecting to the implementation discussion in the
preamble, the petitioners do not challenge any provision of the
promulgated regulations, but rather a discussion in the preamble, e.g.,
75 FR at 35550-54. Although preamble discussions may in some situations
constitute final agency action, it is clear that EPA's particular
discussions in the preamble to this final rule regarding designations
and implementation do not. Rather, the discussions regarding the
potential use of modeling are, at most, non-binding guidance. The
preamble specifically states: ``In many respects, both the overview
discussion below and the subsequent more detailed discussions explain
our expected and intended future action in implementing the 1-hour
NAAQS--in other words, they constitute guidance, rather than final
agency action--and it is possible that our approaches may continue to
evolve as we, States, and other stakeholders proceed with actual
implementation. In other respects, such as in the final regulatory
provisions regarding the promulgated monitoring network, we are
explaining EPA's final conclusions regarding what is required by this
rule. We expect to issue further guidance regarding implementation * *
* EPA intends to solicit public comment prior to finalizing this
guidance.'' Id. at 35550.
    Moreover, nowhere in the preamble (much less in any promulgated
regulation) does EPA state that modeling must be used for designating
areas as attainment, nonattainment or unclassifiable. Thus, the alleged
requirement to which petitioners object does not exist. Rather, the
preamble states: ``We expect that EPA's final area designation
decisions in 2012 would be based principally on data reported from
SO2 monitors currently in place today, and any refined
modeling the State chooses to conduct specifically for initial
designations.'' Id. at 35552. The preamble then goes on to say ``EPA
anticipates making the determination of when monitoring alone is
`appropriate' for a specific area on a case-by-case basis, informed by
the area's factual record, as part of the designation process.'' Id. at
35552 n.22.
    In short, EPA has simply not taken the final agency action alleged
by petitioners, and there is no such rulemaking action for EPA to
reconsider as part of the SO2 NAAQS. To the contrary, the
preamble states that EPA believes that its historic approach to
SO2 designations continues to appear to be appropriate,
while at the same time giving States and other entities the flexibility
to recommend the appropriate mix of data to rely on, including the
possibility of relying entirely on monitoring if supportable. States
and other parties will have opportunities to provide input on

designations and SIP actions before they are issued, see CAA section
107(d)(1)(ii), and those future actions, which would for the first time
constitute final agency action regarding EPA's anticipated approaches,
should be where any claims that EPA may be inappropriately using
modeling can and should be raised. See Pa. Dept. of Envt'l Prot. v.
EPA, 429 F.3d 1125 (D.C. Cir. 2005). At this point, EPA's non-binding
preamble discussion regarding its anticipated approaches in
designations and SIP actions is merely an announcement of general
principles addressing EPA's exercise of its discretion when taking
those actions, and does not impose any requirements on States in those
processes. See Catawba County v. EPA, 571 F.3d 20, 40 (D.C. Cir. 2009).
    EPA therefore rejects the asserted notion that the non-binding
preamble discussion is an ``aspect'' of the final promulgated NAAQS
that must be established as a requirement through notice and comment
rulemaking. EPA always treats implementation issues and establishment
of NAAQS separately and independently, as required by the CAA and the
Supreme Court's ruling in Whitman v. American Trucking Ass'ns. In
advance of taking subsequent designation actions and SIP actions, the
CAA nowhere requires that EPA promulgate an approach to designations or
general implementation, and EPA did not do so here as an ``aspect'' of
the SO2 Primary NAAQS in presenting its discussion of
anticipated implementation approaches, apart from establishing reduced
requirements related to the size of the monitoring network to which
petitioners do not appear to object. EPA similarly rejects the argument
that the non-binding preamble discussion had any kind of final impact
on the promulgated NAAQS. Instead, it is clear from the regulatory text
at 40 CFR 50.17 that the level of the NAAQS is simply expressed as 75
ppb measured in the ambient air as SO2, with a specified
averaging time and form. The additional regulatory language in 40 CFR
50.17(b) and (c) and in Part 50 Appendix T addressing how attainment is
shown via monitoring is specific to when monitoring is used. None of
these provisions is affected in any way by the preamble's discussion of
the ability to also use modeling to assess SO2
concentrations. See 75 FR at 35583; see also section IV.B below. These
provisions are not currently affected by the non-binding guidance, and
they would not have been affected if EPA had either presented its
guidance discussion in the NPRM or had waited until a first designation
or SIP action in which modeling were used, just as the prior
SO2 NAAQS, and related monitoring requirements, set forth in
40 CFR 50.4(a)-(d) and Part 50 Appendix A were never affected by EPA's
and States' use of modeling to assess compliance with those standards
over the last 30 years.
    As mentioned before, many petitioners captioned their petitions
initially as seeking a ``clarification'' that EPA intends to implement
the NAAQS consistently with the promulgated regulatory text, and only
in the alternative sought reconsideration and a new round of notice and
comment proceedings if EPA instead intended to implement the NAAQS
according to the preamble discussion. When those regulatory provisions
in Part 50 addressing assessment of compliance with the NAAQS at an
ambient monitoring site are applicable (i.e., when monitoring is being
used), EPA expects that those provisions will be followed by States and
by EPA. Additionally, since EPA's actual use of implementation
approaches resembling (or refining or departing from) those discussed
in the final rule preamble will be taken in future actions to which
interested parties may provide comments, criticisms, or objections, EPA
will (and must) consider that input before taking final actions. But
because the non-binding preamble discussion of anticipated approaches
does not reflect final action, EPA disagrees that the procedural duties
of CAA section 307(d) that petitioners claim EPA violated even applied
to EPA's guidance, and that the duty to presently reconsider it can
even be triggered.
2. EPA's Implementation Discussions Are Not of Central Relevance to the
Promulgated Decisions on the Final Revised SO2 Primary NAAQS
    Even if EPA's non-binding implementation discussions presented in
the final preamble could have constituted any kind of final action, the
Agency does not regard it as having been of ``central relevance'' to
the regulatory decision on the NAAQS itself. In setting NAAQS that are
``requisite'' to protect public health with an adequate margin of
safety, under CAA section 109(b), EPA establishes standards that are
neither more nor less stringent than necessary for these purposes. In
so doing, EPA may not consider costs of implementing the standards.
Whitman v. American Trucking Associations, 531 U.S. 457, 471, 475-76
(2001). Petitioners frequently assert that the implementation
discussion is an ``aspect'' of the final NAAQS itself in complaining
about the added burden they claim modeling would impose on States and
pollution sources. In fact, issues regarding future implementation are
legally irrelevant to the setting of the NAAQS. And, again, in no
respect does the preamble discussion of modeling as an implementation
tool affect either the promulgated NAAQS in 40 CFR 50.17 or the
provisions addressing when monitoring is used to assess compliance.
Consequently, we reject petitioners' assertions that the non-binding
preamble discussion of the possible future implementation approaches is
``of central relevance'' to the promulgation of the SO2
Primary NAAQS or to the monitoring network design requirements, and we
therefore conclude that reconsideration of the rule in light of that
discussion is not warranted.
    An objection is of central relevance if it provides substantial
support for the argument that the underlying promulgated decisions, in
this case the NAAQS set forth in 40 CFR 50.17 and requirements
addressing network design requirements for monitoring, should be
revised. None of the petitioners' arguments summarized above provide
substantial support for such a claim. Even in complaining that the use
of modeling may be difficult, if attempted, and in their
characterizations of the NAAQS as an allegedly ``probabilistic''
standard and of modeling as a ``deterministic'' tool, they present no
information indicating that the scientific conclusion of what NAAQS is
requisite to protect public health with an adequate margin of safety is
erroneous. Nor do they explain how the regulatory provisions in Part 58
are erroneous for the purpose of network design. A petition for
reconsideration cannot merely object to a non-binding guidance
discussion and claim that is sufficient to require initiation of the
reconsideration of related, but not affected, promulgated regulations.
Allegations that such a discussion is of central relevance will not
suffice. To justify reconsideration, a petitioner has to show why the
objectionable guidance discussion demonstrates that the Agency's
underlying decision on the promulgated NAAQS should be changed.
    Petitioners have not met this burden. The core defect in
petitioners' arguments is that they do not address the scientific
evidence regarding the NAAQS, and do not address the policy or
technical rationale supporting EPA's promulgated revisions to the
network design monitoring requirements. TCEQ's and others' claims that
the guidance discussion conflicts with the

``form'' of the NAAQS are misplaced. The form of the NAAQS defines the
air quality statistic that is to be compared to the level of the
standard in determining whether an area attains the standard. See 75 FR
6474, 6479 n. 5 (Feb. 9, 2010). For the revised primary SO2
NAAQS, the form is the three year average of the 99th percentile of the
daily maximum 1-hour average concentrations of SO2. EPA
justified in detail its decision to revise the previous expected
exceedance-based form with a percentile-based form, as well as its
choice of using the 99th percentile of the air quality distribution. 75
FR at 35539-41. Air quality distributions can, of course, be generated
by modeling tools or by monitoring. See REA section 8.4 where EPA
generated one-hour SO2 air quality distributions in the
exposure analysis. In any case, all such questions are fact-dependent
and await specific circumstances for resolution. Indeed, if EPA had
first presented its non-binding discussion on implementation in the
NPRM, and had said no more on this subject in the final rulemaking
notice, it would not have failed to promulgate any required regulatory
``aspect'' of the NAAQS itself, and such placement of the discussion in
the NPRM would not have made it of any more central relevance to the
separate scientific decision of whether the NAAQS should be revised and
how, or to the reasonableness of the limited promulgated requirements
relating to minimum size of a monitoring network. Although
implementation guidance discussions may be of central relevance to
future actions that employ approaches discussed therein, they are not
so regarding final promulgated NAAQS that are required to be based on
entirely different criteria--and may not be based on cost of
implementation considerations at all--where the rulemaking does not
actually promulgate implementation requirements. Thus, the
implementation discussions to which petitioners object could not
lawfully be of central relevance to the promulgated SO2
Primary NAAQS. See Whitman v. American Trucking Associations, 531 U.S.
471, 475-76.
3. EPA's Implementation Discussions Were Logical Outgrowths of the
Proposed Rule
    Even if the preamble's non-binding implementation discussion could
be both ``final action'' and ``of central relevance'' to the outcome of
the promulgated NAAQS decision, we consider the discussion to be a
``logical outgrowth'' of the proposal. The CAA does not require us to
have presented the discussion in the NPRM before we could further
address the expected implementation approaches in the final rule's
preamble or in other guidance documents. The NPRM contained initial
discussions of how the proposed revised NAAQS might be implemented, and
therefore the general issues and related specific issues regarding
implementation were squarely opened up for public comment. Although the
NPRM did not specifically address this fact, it has long been EPA's
practice in implementing the prior SO2 Primary NAAQS to rely
upon both modeling and monitoring to determine whether areas have
attained the NAAQS. See, e.g., EPA's February 1994 SO2
Guideline Document (available at http://www.epa.gov/ttn/oarpg/t1/memoranda/SO2_guide_092109.pdf) at 2-5 (``For SO2
attainment demonstrations, monitoring data alone will generally not be
adequate.'') and at 2-1 (``Attainment determinations for SO2
will generally not rely on ambient monitoring data alone, but instead
will be supported by an acceptable modeling analysis which quantifies
that the SIP strategy is sound and that enforceable emission limits are
responsible for attainment.''). The NPRM was published with this
history of prior SO2 NAAQS implementation, and there was no
reason for any interested party to have assumed that over 30 years'
worth of prior implementation actions might not have some bearing on
the way a revised NAAQS might be implemented.
    To the extent the NPRM, in not explicitly discussing that prior
history, was interpreted by interested parties to announce a proposed
change to that longstanding practice, the rulemaking process inherently
leaves open the possibility that an agency will choose not to adopt any
proposed change. Therefore, interested parties could have foreseen that
EPA might not, in fact, make any such change but instead discuss our
expectation to continue our past practice, and they had ample
opportunity to comment on that possibility or ask directly whether EPA
intended to no longer follow it. In such circumstances, affected
parties can be expected to be aware that not adopting a change
reflecting a departure from the Agency's prior practice is a
possibility. See American Iron & Steel Inst. v. EPA, 886 F.2d 390, 400
(D.C. Cir. 1989) (``One logical outgrowth of a proposal is surely, as
EPA says, to refrain from taking the proposed step.'').
    In fact, some interested parties did comment on the related issue
of the burden of relying on monitoring, and suggested that EPA instead
use modeling to relieve that administrative burden. See 75 FR at 35551.
Moreover, ASARCO notes that it and others commented on their view that
modeling is overly conservative, when used to assess compliance. Partly
in response to comments, EPA explained its anticipated approaches of
continuing to rely upon both modeling and monitoring, and made clear
that except for the promulgated provisions relating to the scope of the
monitoring network and associated requirements, the Agency was still
developing its policy for future actions such as area designations and
determinations of NAAQS attainment, and would decide whether to base
such actions on modeling or monitoring on a case-by-case basis through
rulemaking. It cannot credibly be asserted that EPA's mind does not
remain open to other views following these explanations.
    Petitioners' arguments that providing an opportunity for public
comment on future guidance documents would not cure EPA's alleged
procedural defect in the final preamble discussion ignore the fact that
such an opportunity necessarily will be provided in subsequent
regulatory actions issuing designations and acting in response to SIP
submissions. While the CAA does not require that EPA provide an
opportunity for public comment on designations, States initiate the
process and present their own views to EPA in submitting designations
recommendations, and EPA's responses to those recommendations must be
well-reasoned and are judicially reviewable. Further, EPA has recently
elected to provide a brief public comment period on designations as
well. SIP actions undergo public notice and comment in two stages, once
at the state level and again at the federal approval/disapproval stage.
    Thus, while EPA disagrees with the petitioners' view that the non-
binding preamble discussion on future implementation represents final
agency action of central relevance to the NAAQS decision, even if the
final rule's guidance discussion were to have final effect, EPA
committed no procedural error in presenting this discussion in the
final rule's preamble, and reconsideration is not warranted. This is
true particularly as further administrative process in which objections
can be raised before binding actions are taken will be provided before
any of EPA's discussion has a direct and binding effect in any specific
case, which will be based on the relevant facts of its own situation,
which even EPA's allegedly ``adopted'' guidance explicitly provides.

4. EPA Is Not Required To Promulgate Regulatory Requirements Regarding
NAAQS Implementation and May Discuss Implementation Issues Through Non-
Binding Guidance
    As explained above in our explanation for why petitioners'
objections are not of central relevance to the outcome of the revised
NAAQS, EPA disagrees with petitioners' assertions that the Agency is
required under the CAA to promulgate, as regulatory provisions,
requirements addressing future implementation of the NAAQS of the type
petitioners demand. Nothing in CAA sections 107(d), 110 or 192, or
anywhere else in the CAA requires this. The prior SO2
Primary NAAQS rulemaking did not contain such regulatory requirements
on implementation, while EPA has provided numerous guidance documents
for implementing the prior SO2 NAAQS that address issues
such as the use of modeling. See, e.g., SO2 Guideline
Document, Office of Air Quality Planning and Standards, Research
Triangle Park, NC 27711, EPA-452/R-94-008, Feb. 1994. Moreover, EPA
does not assume that petitioners thought that the proposed monitoring
network of less than 400 monitors would have generated data from the
nationwide inventory of significant sources of SO2.
Petitioners never commented that EPA should have proposed additional
measurement requirements to cover situations in which monitors would
have been unusable to predict future source emissions, or were simply
non-existent in an area that sought designation as attainment or non-
attainment and was in search of some kind of supporting factual record.
Consequently, we disagree with petitioners' claims that it is now
improper to continue to address implementation issues in non-binding
guidance such as that which EPA has frequently issued regarding
SO2 NAAQS implementation and which EPA presented in the
preamble. Although we stress that the preamble's inclusion of such
guidance and statements regarding the intent to issue further guidance
do not warrant reconsideration of the final rule, we also note that the
continued development of guidance necessarily represents a continuing
evaluation and ``reconsideration'' of the issues addressed therein, and
we fully expect to continue to evaluate implementation issues as we
proceed to develop such guidance and take implementing actions. In sum,
EPA denies petitioners' procedural claims because EPA was not required
to issue initial guidance through use of notice and comment rulemaking.

IV. Statutory and Regulatory Issues

A. Summary of Petitioners' Arguments

    In addition to their procedural objections, the petitioners raise
several objections based on their views that EPA's implementation
discussion provided in the final rule preamble conflicts with
applicable statutory and regulatory provisions. At the outset, EPA
regards it as impossible for our non-binding guidance to have an
effective ``conflict'' with the CAA or our regulations, as it is not
final and imposes no independent requirements. Thus, we respond to
petitioners' arguments conditionally, while reserving the right to
reach different final conclusions than are reflected in our
preliminary, non-final responses provided here if petitioners were to
raise these and other objections in the context of future final actions
such as designations or SIP approvals/disapprovals.
1. Consistency With ``Cooperative Federalism'' of CAA
    Several petitioners raise a broad philosophical objection to EPA's
non-binding implementation discussion, namely that it is allegedly in
conflict with the scheme of ``cooperative federalism'' of the CAA under
which States are to be given the first opportunity, before EPA, to make
judgments regarding how pollution sources should be controlled in order
to attain the NAAQS. UARG asserts that the discussed anticipated
modeling approach ``usurps the role that States are to play when making
[section] 107(d) designations and thus is inconsistent with
[c]ongressional intent.'' UARG at 18. In the 1977 Amendments to the CAA
that added section 107, UARG claims, States were ``the basic units from
which pollution control decisions, plans, administration, and
enforcement would follow. On the other hand, the federal government's
role was merely to provide guidance and set national standards.'' Id.
at 25, citing H.R. Rep. No. 95-294, at 289 (1977). UARG then claims
that Congress ``granted States the power to make initial designations
of areas within State borders.'' Id. In support of this claim, UARG
cites the legislative history of differing versions of the bills
addressing designations in the 1990 CAA Amendments, and claims that the
House Report shows the bill ``was amended to leave the States' power
intact.'' Id. at 26. UARG then claims that case law supports the view
that States are given deference in determining whether areas are
designated as attainment, nonattainment or unclassifiable. Id., citing
Pa. Dept. of Envtl Prot. v EPA, 429 F.3d 1125, 1129 (D.C. Cir. 2005).
UARG asserts that EPA's final rule ``directs States to submit [section]
107(d) attainment/nonattainment designation recommendations by June 2,
2011,'' and that if States ``must use modeling'' that ``EPA now appears
to require,'' they will not be able to do so due to EPA's not yet
having provided additional guidance. Id. at 26-27. ``This essentially
deprives States of their powers to make their [section] 107(d)
designation recommendations by the compliance deadline,'' and ``will
limit the ability of States to use their sound judgment in making
designation recommendations and developing maintenance SIPs,'' UARG
claims. Id. at 27.
    ASARCO endorses UARG's claims, and adds that ``EPA appears to be
usurping the role of the State in an effort to impose more stringent
controls on sources than may be necessary because of overly
conservative modeling results even where monitoring may show no
exceedances of the revised NAAQS.'' ASARCO at 10. TCEQ less explicitly
raises this objection, but argues in several places that states such as
Texas have primary responsibility in implementing the NAAQS and have
been left in ``an untenable position'' of having to make designation
recommendations before EPA provides further modeling guidance. TCEQ at
2-3, 15. North Dakota and South Dakota echo these points, arguing that
EPA's guidance discussion ``limits the role that Congress intended
States to play in the ambient standard implementation process, and it
limits the discretion that States [are] to have in choosing the
appropriate tools for making determinations of whether or not areas
within their jurisdiction are attaining'' the NAAQS. ND and SD at 4.
They explain that they currently use monitors to measure ambient
pollution levels, and that models can be difficult and time-consuming
to use and are allegedly less accurate, predicting higher pollution
levels than monitors detect. Id. at 5. As EPA has not yet provided
additional specific guidance on how to use modeling for the new NAAQS,
States will not be able to undertake the designations recommendation
work that EPA ``is insisting'' they perform. Id. This deprives states
of their authority under section 107(d), North Dakota and South Dakota
assert, and is compounded by EPA's discussion that ``require[s] the use
of conservative modeling'' in section 110(a)(1) SIPs that would be due
from

unclassifiable areas, if States choose to not perform modeling in time
for initial designations. Id., at 6.
2. Consistency With CAA Section 107(d) Designation Requirements
    UARG disputes EPA's preamble explanation that it has previously
employed modeling in making designations under CAA section 107. UARG at
6-9, 19. UARG states that the examples of prior actions cited in EPA's
discussion cites, instead, address situations where EPA decided to not
change a designation of nonattainment because modeling showed
violations where monitoring did not, or addressed instances where EPA
issued a SIP call for an attainment area based on modeled violations.
Id. at 19-20. Although States sometimes choose to use modeling, UARG
claims EPA has ``never before required States to conduct modeling data
to make their initial attainment designations.'' Id. at 20. UARG then
asserts that EPA's prior guidance reflects a preference for monitoring
over modeling, including when there is a conflict between the two, and
that in the context of other NAAQS EPA has clearly favored monitoring.
Id. at 20-21, n. 38.
    NEDA/CAP, without further analysis regarding section 107(d), claims
that EPA's discussion ``is a significant departure from prior
procedures for designating areas and re-designating unclassifiable
areas.'' NEDA/CAP at 5. ASARCO objects that EPA has not explained how
``its modeling proposal will meet'' the requirements of CAA section
107(d)(3)(E)(i) and (iii) that an area show it has attained the NAAQS
based on permanent and enforceable reductions in emissions. ASARCO at
11. North Dakota and South Dakota's federalism objections also reflect
their arguments that EPA's guidance is inconsistent with CAA section
107, which they interpret as giving States the ability to use their
sound judgment, as opposed to EPA's, in making designation
recommendations. ND and SD at 4-5. They claim monitoring is preferable
to modeling to implement section 107(d), is more accurate, and will
avoid overestimating SO2 concentrations that result in
nonattainment designations triggering the requirement for pollution
controls to solve ``problems that do not exist in the real world.'' Id.
at 5-6. For example, use of modeling to designate areas under section
107 might result in electric utility plants being forced to control
their SO2 pollution with ``potentially unfeasible emission
control requirements'' that cause electricity rates to increase
substantially. Id. at 6. WVDEP asserts that EPA's guidance discussion
``radically departs from agency practice in the last three revised
NAAQS. WVDEP at 2. ADEQ echoes these concerns by stating that
attainment status determinations will be impracticable until EPA issues
further guidance on modeling, which is not expected before States have
to make designation recommendations under section 107. ADEQ at 1.
3. Consistency With CAA Section 110 SIP Planning Requirements
    UARG outlines the 1970 version of the CAA section 110(a)(1) SIP
requirements, and asserts that EPA's guidance discussion is ``the first
time that EPA stated its intent to use air quality modeling in the
development of SIPs under [section] 110(a)(1),'' and notes that
previously EPA has required SIPs that only included a PSD program and
``other infrastructure SIP elements.'' UARG at 4, 6, 9-10, 21. UARG
claims EPA ``is now interpreting [section] 110(a)(1) to require that a
State'' demonstrate NAAQS attainment and maintenance via dispersion
modeling. Id. at 15, 21. UARG therefore claims that the guidance
discussion ``significantly changes the way EPA interprets requirements
for maintenance SIPs.'' Id. at 22. NEDA/CAP echoes this claim. NEDA/CAP
at 3.
    TCEQ objects to EPA's alleged ``divergence from CAA section
110(a)(1) and (2) attainment and maintenance requirements for all
areas, whether designated nonattainment or not.'' TCEQ at 5. TCEQ
claims EPA's guidance discussion ``significantly changed the planning
requirements for attainment and `unclassifiable' areas--those areas
that do not have sufficient monitoring or modeling data to show
attainment of the NAAQS.'' TCEQ at 10. Like UARG, TCEQ unfavorably
compares the guidance discussion's outline of an expected SIP that
shows the area meets the statutory elements of 110(a)(1), to what EPA
previously accepted as approvable. TCEQ at 10-11. North Dakota and
South Dakota also object to the guidance discussion's description of
expected section 110(a)(1) SIPs that would ``force the States to devote
substantial time and resources'' to addressing modeled SO2
concentrations and impose costly and potentially unfeasible emission
control measures. ND and SD at 6. WVDEP objects to how EPA discusses it
would treat unclassifiable areas under the SO2 program
compared to other NAAQS pollutants. WVDEP at 2.
4. Consistency With CAA Section 171(2) Definition of ``Nonattainment
Area''
    Two petitioners attempt to buttress their objections with claims
that EPA's guidance discussion conflicts with how Congress revised the
statutory definition of ``nonattainment area'' in the 1990 CAA
Amendments to section 171(2). NEDA/CAP asserts that ``Congress repealed
the language from Section 171(2) which allowed states to use either
modeling or monitoring for its attainment designation.'' NEDA/CAP at 5.
Prior to 1990, NEDA/CAP observes, section 171(2) defined
``nonattainment area'' as one ``which is shown by monitored data or
which is calculated by air quality modeling (or other methods
determined by the Administrator to be reliable) to exceed any
[NAAQS].'' Id. But in 1990 Congress deleted references to the type of
data used to identify NAAQS nonattainment, which NEDA/CAP claims means
that it is ``arbitrary and capricious for EPA to rely entirely on
modeling to determine whether an area is meeting the NAAQS.'' Id. It
argues that the Senate Committee's report supports this view, in
stating that ``EPA may rely for these designations on sound data that
is available, preferably air quality monitoring data, but in some cases
where appropriate and necessary, the [EPA] may rely on modeling or on
statistical extrapolation from monitored concentrations of another
pollutant.'' S. Rep. No. 101-228, at 15 (1989). TCEQ endorses this
reading as a ``clear direction by Congress that modeling is not to be
used to determine nonattainment areas for a NAAQS pollutant,'' as part
of its argument that there is no possible way the public could have
foreseen that EPA would ``require modeling for compliance and
implementation.'' TCEQ at 12-13.
5. Consistency With SO2 Primary NAAQS Regulatory Text
    All petitioners except MSCC argue that EPA's guidance discussion
conflicts with the promulgated regulatory text of the NAAQS. UARG
argues that the promulgated regulatory text of the final rule ``nearly
mirrors the language'' of the proposed rule regarding the use of
monitoring to measure SO2 concentrations, but the preamble's
guidance discussion suggests EPA ``intends to require the use of air