
[Federal Register Volume 76, Number 17 (Wednesday, January 26, 2011)]
[Rules and Regulations]
[Pages 4780-4800]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-1353]



[[Page 4779]]

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  

[[Page 4780]]


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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: (919) 541-7524; fax (919) 
541-0237; e-mail: stewart.michael@epa.gov.

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

[[Page 4781]]

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

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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

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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

[[Page 4784]]

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

[[Page 4785]]

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,

[[Page 4786]]

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

[[Page 4787]]

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

[[Page 4788]]

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.

[[Page 4789]]

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

[[Page 4790]]

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

[[Page 4791]]

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

[[Page 4792]]

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

[[Page 4793]]

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

[[Page 4794]]

``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.

[[Page 4795]]

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

[[Page 4796]]

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 
quality modeling analyses.'' UARG at 1, 14-15. UARG notes that the 
regulation does not require States to use modeling for section 107(d) 
designations or for section 110(a)(1) SIPs. Id. at 16. ``Given the 
difference between the preamble discussion and the actual regulatory

[[Page 4797]]

language,'' UARG asks that EPA clarify that the regulatory language 
reflects how EPA intends the NAAQS to be implemented. Id.
    NEDA/CAP contrasts the regulatory text of 40 CFR 50.17(b) and of 
Appendix T, which apply to situations where monitoring is used, to 
EPA's guidance discussion regarding modeling, echoing UARG's view that 
the final regulation ``nearly mirrors'' the proposed regulatory text. 
NEDA/CAP at 2-3. NEDA/CAP asserts that ``the rule is therefore 
internally inconsistent and confusing,'' and similarly requests that 
EPA clarify that the NAAQS will be implemented according to the 
regulatory text. Id. at 3. ASARCO argues that the revised regulatory 
text, like the prior SO2 NAAQS' text at 40 CFR 50.4, refer 
to attainment for SO2 based on measuring ambient air 
concentrations through monitoring. ASARCO at 4. ASARCO then endorses 
UARG's view that the preamble discussion is inconsistent with ``the 
plain language of the Final Rule.'' Id. at 10, n. 12.
    TCEQ contrasts the regulatory text not just with the general 
preamble guidance discussion but also with specific preamble language 
addressing the relationship of the regulatory text applicable to 
monitoring situations to other possible methods for assessing 
SO2 levels. TCEQ at 5, 9-10. TCEQ asserts that EPA's 
statement recognizing that the monitoring-specific language does not 
speak to other measurement approaches ``commits EPA to interpret [its] 
adopted rule language in a way that inherently conflicts with the plain 
language of the rule,'' which TCEQ says the Agency may not do. Id. at 
9-10. TCEQ claims EPA undertook this ``change in its interpretation'' 
without notice and comment procedures in contravention of Paralyzed 
Veterans of America, et al., v. D.C. Arena L.P., 117 F.3d 579, 586 
(D.C. Cir. 1997), and that EPA's ``error is compounded by the fact that 
EPA interprets the rule language as permissive, while stating elsewhere 
in the Final Rule that monitoring data demonstrating attainment will 
not be deemed adequate'' absent confirming modeling data. Id. at 10, n. 
37.
    North Dakota and South Dakota also claim the guidance discussion is 
inconsistent with the regulatory provisions, and ask EPA to clarify how 
it intends States to implement the NAAQS. ND and SD at 2-3, 4, 7. Like 
the other petitioners, they focus on the regulatory text that 
specifically addresses situations in which monitors are required to be 
used. Id. at 4. ADEQ endorses North Dakota's and South Dakota's 
position. ADEQ at 1. WVDEP takes a different approach from other 
petitioners, characterizing the final regulatory text of 40 CFR 
50.17(b) as a ``substantive alteration'' that ``implies that monitored 
air quality data cannot represent, for regulatory purposes, an area 
larger than the site boundaries,'' which WVDEP calls a ``fundamental, 
disturbing change from past practice.'' WVDEP at 1.

B. Responses to the Petitioners' Statutory and Regulatory Arguments

    As stated earlier, EPA regards it as impossible for our non-binding 
preamble guidance to have an effective ``conflict'' with the CAA or our 
regulations, as it is not final and imposes no independent 
requirements. Only in subsequent designations actions under section 107 
or in SIP actions under sections 110 or 192 would the objections 
petitioners raise relate to final actions that could theoretically 
represent the ``conflicts'' that petitioners allege. 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.
    Regarding the claimed conflict with federalism principles 
underlying the CAA that place primary responsibility for implementation 
on States and restrict EPA's roles, EPA has taken no action that can be 
characterized as encroaching in States' roles in future implementation. 
As EPA explained in the preamble, decisions on what data should be used 
to support individual designations or SIP actions will be made on case-
by-case bases and through future rulemaking, and States are not 
restricted by our non-binding guidance from recommending designations 
based on monitoring, modeling, or a combination. We have, however, as 
we commonly do in advance of designations under revised NAAQS, provided 
guidance regarding what we currently expect would provide the most 
accurate data to support those actions, and we expect to provide 
further guidance. Even the petitioners, in their objections, concede 
that providing guidance for stakeholders to subsequently use is an 
appropriate role for EPA. It is difficult to understand how this can 
result in EPA having presently usurped States' roles in future 
implementation. Moreover, EPA notes that although it is true that 
States have the initial role of recommending designations under CAA 
section 107(d) and in developing and submitting for approval SIPs under 
sections 110 and 192 to show implementation, attainment, maintenance 
and enforcement of the SO2 NAAQS, EPA has the ultimate 
responsibility to make final decisions in these actions, whether or not 
States even fulfill their own initial roles. See, e.g., CAA sections 
107(d)(1)(B)(ii), 107(d)(3)(E), and 110(c)(1)(A)-(B). Moreover, as the 
DC Circuit explained in response to similar arguments that EPA guidance 
in the designations process ``impermissibly encroaches on states' 
statutory prerogative to have a first-say on area designations within 
their borders,'' although EPA indeed must wait its turn following the 
period for States to recommend designations before EPA makes any 
individual designations, ``nothing in section 107(d)(1) prevents EPA 
from developing general principles to govern its exercise of discretion 
when the time comes, or from announcing those general principles before 
the states submit their initial designations. To the extent petitioners 
think that EPA owes the states a measure of substantive deference under 
section 107(d)(1) [* * *] we disagree. Though EPA may, of course, go 
along with states' initial designations, it has no obligation to give 
any quantum of deference to a designation that it `deems necessary' to 
change.'' Catawba County v. EPA, 571 F.3d at 40 (emphasis in original).
    Similarly, EPA does not agree that its guidance discussion can 
presently pose a ``conflict'' with either the terms of CAA section 107 
or the Agency's past practice in issuing designations and re-
designations, as petitioners assert. EPA has not yet taken any 
designation action that arguably ``departs'' from our past practice, 
and as petitioners concede, the final regulation itself does not impose 
a binding requirement that States conduct modeling in the manner to 
which petitioners object. EPA observes, however, that the Agency has 
previously extensively used modeling to support designation and re-
designation decisions for the SO2 primary NAAQS, as 
explained in the preamble, and that our long-standing guidance supports 
this approach for SO2 NAAQS, particularly in the absence of 
monitoring data. See, e.g., Memorandum from John S. Seitz, Director, 
Office of Air Quality Planning and Standards, to Regional Office Air 
Division Directors, ``Redesignation of Sulfur Dioxide Nonattainment 
Areas in the Absence of Monitored Data,'' Oct. 18, 2000; Memorandum 
from Sheldon Meyers, OAQPS Director, ``Section 107 Designation Policy 
Summary,'' April 21, 1983. [Available at: http://www.epa.gov/ttn/naaqs/so2/so2_tech_res.html].

[[Page 4798]]

    EPA does not agree that the preamble discussion of the possible 
approach of implementing CAA section 110(a)(1) actually imposes a 
requirement to demonstrate attainment with the revised NAAQS on a 
specific schedule as a consequence of the final rule. As petitioners 
observe, we have not promulgated such a requirement, and the 
application of this approach in a future section 110(a)(1) SIP approval 
or disapproval action would be the first instance in which EPA could 
allegedly act in conflict either with the applicable provisions of 
section 110(a)(1) itself or with our prior practice regarding this 
provision for SO2 or any other NAAQS pollutant. If any 
interested party objects to such an approach that EPA might propose in 
such a future action, EPA will respond to that objection then. In the 
meantime, we note that section 110(a)(1) is fairly straightforward in 
providing that following revision of a NAAQS States are to adopt and 
submit SIPs that ``provide[] for implementation, maintenance, and 
enforcement'' of the NAAQS, and EPA is required on a case-by-case basis 
to take action under CAA section 110(k)(3) to approve or disapprove 
such a SIP based on whether it meets the applicable requirements of the 
Act. EPA has not yet ``significantly changed'' how this statutory 
requirement applies.
    As for the argument that the 1990 CAA amendment to section 171(2)'s 
definition of ``nonattainment area'' forces a conflict with the EPA's 
preamble discussion, again, EPA does not consider it possible for non-
binding guidance to create such a conflict. Petitioners should present 
this argument, if at all, in the context of an actual implementation 
action that could theoretically cause such a conflict. Moreover, 
petitioners' argument appears to make the remarkable claim that because 
the amended section 171(2) definition removed explicit reference to 
both monitoring and modeling, it somehow follows that EPA may use the 
former type of non-referenced data to support nonattainment 
designations but may not use the latter. It is not clear how the 
statutory text can compel this result, and the legislative history 
cited by petitioners appears to endorse the use of both monitoring and 
modeling, as necessary and appropriate, on a case-by-case basis. 
Clearly, the opportunity to endorse or object to the use of either 
monitoring or modeling (or some combination) will be available in 
future implementation actions, but it is not apparent that Congress 
issued an absolute prohibition on the use of modeling that EPA's 
guidance in advance of such an action could violate.
    In response to the arguments that the preamble guidance conflicts 
with the promulgated regulatory text of the final rule, again EPA 
points out that there can be no such effective conflict between 
promulgated final action (the regulations) and non-binding guidance 
discussions that address how EPA may act in future. The final 
regulatory text is binding, as are the final preamble explanations of 
how that specific regulatory text must be implemented, but the rest of 
EPA's implementation discussion is not.
    In any case, EPA addressed the relationship of the regulatory 
provisions in section 50.17 (b) referring to ``at an ambient monitoring 
site'' and similar provisions in Part 50 Appendix T related to when the 
primary NAAQS for SO2 ``are met at an ambient air quality 
monitoring site'' and the non-binding guidance elsewhere in the 
preamble relating to potential implementation strategies. EPA stated 
that the references to monitoring in the rule ``makes clear that the 
regulatory text refers to situations where compliance with a NAAQS is 
measured by means of monitoring. This 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.'' 75 FR at 33582. There consequently is no such conflict as 
petitioners allege, even if EPA's implementation discussions were other 
than non-binding initial guidance. Thus, where monitoring is used, 
sections 50.17 and the corresponding provisions in Part 50 Appendix T 
are to be followed. But where on case-by-case bases additional tools 
are used to accurately assess SO2 concentrations, such as 
where monitoring would not yield reliable data of the maximum 1-hour 
daily concentrations in an area or location, it is clear that States 
and EPA may make use of those tools separate from the regulatory 
provisions governing monitoring's use to evaluate whether the ambient 
air quality exceeds the NAAQS for SO2, as defined by the 
specified level, averaging time, and form. Nothing in the Act prohibits 
this approach. See, e.g., CAA sections 107(d)(3) (any ``air quality 
data'' may be used for redesignations); 110(a)(1) (does not address the 
issue of the types of data States may use in devising plans for 
implementation, maintenance, and enforcement of a primary NAAQS); 
192(a) (does not specify the types of data that may support a 
demonstration that a non-attainment area has attained a NAAQS). Again, 
only in those possible future actions would it be possible to evaluate 
whether the State's or EPA's implementation actually then ``conflicts'' 
with the regulatory text.
    Finally, it must be repeated that whether monitoring or modeling is 
used in assessing compliance with the NAAQS, all elements of the NAAQS 
must be satisfied so that the ultimate determination remains identical: 
whether the three-year average of the 99th percentile of daily maximum 
1-hour average concentrations of SO2 exceed 75 ppb. The 
preamble discussion of implementation approaches is consistent with, 
and does not affect, this requirement.

V. Impact on Final Standard Issue

A. Petitioners' Arguments

    Several petitioners claim that EPA's guidance discussion has a 
present impact on the promulgated NAAQS, either to make it more 
stringent, of the wrong ``form,'' or impossible to measure compliance 
with. UARG asserts that the guidance ``has the effect of making the new 
standard more stringent than the lower end of the range of the standard 
in the Proposed SO2 Rule because of the conservatism of 
modeling analyses.'' UARG at 18. Later, however, UARG states that ``the 
new 1-hour standard for SO2 could effectively become more 
stringent than the lower end of the 50 to 100 ppb range that was 
proposed for comment based on studies that relied on monitored 
SO2 levels.'' Id. at 28 (emphasis added). ``EPA's 
recommended approaches for modeling of sources of SO2--
including EPA's insistence on the use of peak emission rates for all 
modeled sources--will in all likelihood substantially over-predict 
concentrations of SO2 thereby possibly falsely indicating 
violations of the new 1-hour SO2 NAAQS.'' Id. at 28-29 
(emphasis added). UARG continues that ``[m]odeled predictions of source 
impacts will also likely be unrealistically high because of the 
approaches that are being used to determine the regional background 
values that should be added to predicted source impacts. [* * *] 
Although EPA does not require States to use this approach, the Agency's 
failure to have in place rules that suggest better options make[s] it 
likely that States could continue their current practice.'' Id. at 29 
(emphasis added). ``In short,'' UARG argues, ``because models routinely 
over-predict short-term concentrations of SO2, the use of 
modeling to assess compliance with the new SO2 standard 
could have the effect of making the new SO2 standard--as 
implemented--more stringent than 75 ppb and, indeed,

[[Page 4799]]

could effectively make the standard more stringent than even the lower 
end of the 50 to 100 ppb range that EPA'' proposed. Id. (emphasis 
added).
    ASARCO cites Appalachian Power Co. v. EPA, 208 F.3d at 1027, and 
Donner Hanna Coke Corp., 464 F. Supp. At 1304, for the proposition that 
the method of determining compliance can affect the stringency of the 
standard or the level of performance needed to meet the standard. 
ASARCO at 11. ASARCO notes that it commented on the proposed rule to 
claim that current modeling is conservative and that there is a 
discrepancy between modeling and monitoring data. Id. ``How attainment 
must be demonstrated similarly can affect the stringency of the 
standard and the requirements that may be imposed on sources within the 
area,'' ASARCO asserts. Id. (emphasis added).
    TCEQ, with the endorsement of ADEQ (see ADEQ at 2), makes a 
different kind of argument, alleging that EPA's guidance discussion 
lacks an explanation for ``why dispersion modeling is an appropriate 
comparison or `fit' for the form of the standard,'' and that EPA's 
actual promulgation of 40 CFR 50.17(b) governing compliance shown by 
monitoring is itself arbitrary and capricious. TCEQ at 3. The guidance 
results in ``an inappropriate form of the standard,'' TCEQ claims, 
which it asserts is ``probabilistic'' as opposed to ``deterministic,'' 
which it considers EPA's generally preferred modeling method to be. Id. 
at 5-9. TCEQ states that in the REA, EPA developed a statistical model 
to determine 5-minute peak SO2 concentrations and concluded 
that at a given level of SO2, a 99th percentile form of a 1-
hour standard is effective at limiting 5-minute peak SO2 
concentrations. Id. at 5-6. TCEQ characterizes the form of the final 
NAAQS as ``the 3-year average of the 99th percentile of the annual 
distribution of daily maximum 1-hour average concentrations,'' as set 
forth in 40 CFR 50.17(b) applicable to situations in which monitoring 
is used. Id. at 6. TCEQ states that following the proposed 
SO2 NAAQS, EPA issued guidance regarding implementation of 
the PM2.5 and NO2 NAAQS which indicates there is difficulty 
integrating modeling and monitoring data, which ``would also be true 
for the SO2 standard.'' Id. at 6-7. TCEQ complains that EPA 
has, like for PM2.5 and NO2, adopted a ``form'' of the 
SO2 NAAQS for which the Agency has not yet explained how to 
translate the modeling results into a form appropriate for comparison 
to the new standard. Id. at 7. TCEQ asserts EPA must refine modeling 
procedures to ``realistically address the frequency of peak short-term 
impacts in order to appropriately implement the new 1-hour 
SO2 NAAQS,'' and that the ``joint frequency of worst-case 
cumulative emissions and adverse dispersion conditions become more 
important for probabilistic ambient standards.'' Id.
    EPA's preferred model for SO2 implementation, 
``AERMOD,'' instead, is a ``deterministic'' model that provides point 
estimates based on a worst-case set of input parameters that TCEQ 
argues is not appropriate for probabilistic standards. Id. at 7-8. Use 
of peak emissions for all sources on a continuous basis will lead to 
overestimates of the frequency of peak total impacts, TCEQ claims, 
while a model should instead consider the use of a frequency 
distribution of emissions for the sources being considered in order to 
``match'' the adopted form of the standard. Id. at 8. TCEQ recognizes 
that EPA allows States to propose to use other models than AERMOD, but 
complains that EPA ``requires an arduous demonstration before [it] will 
approve the use of other models.'' Id. TCEQ claims that EPA's preferred 
air dispersion models have not been developed to predict short-term 
locations of maximum concentration or account for a probabilistic 
standard. Id. TCEQ claims that where the probability of simultaneous 
occurrence of peak emissions and worst-case meteorology is low, 
standard modeling will exaggerate ambient concentrations, particularly 
where sources do not operate continuously and make ``overly 
conservative'' modeled projections inappropriate for use in 
designations. Id. at 8-9.

B. EPA's Response

    First, as UARG's arguments suggest by their own terms, and as we 
have explained regarding the other procedural and substantive 
objections petitioners raise, the claims that EPA's discussion has an 
impact on the promulgated standard ignore the fact that the guidance is 
not final binding action that has any immediate and direct effect on 
anything. As UARG appears to recognize, future implementation actions 
using EPA's ``recommended'' approaches which EPA ``does not require'' 
``could'' have an impact by ``possibly'' or ``likely'' resulting in 
States using modeling in a way to ``likely'' overestimate 
SO2 emissions only if, in fact all of that actually occurs, 
which it may not. Thus, UARG's claim as presented necessarily concedes 
that any arguable impact on NAAQS compliance of the guidance discussion 
is speculative at this point. There is no reason to accept this result 
as inevitable, and if, in a given case (such as PSD permitting), UARG 
believes that a particular modeling method is over-predicting 
SO2 emissions in a manner that is not representative of a 
source's potential to cause or contribute to a NAAQS exceedance, it 
will in that future action be able to object based on the facts then 
presented. But here there are no such facts to dispute, and it is 
therefore not possible for the guidance itself, as expressed in EPA's 
preamble, to have any impact on the NAAQS.
    Likewise, ASARCO's objection raises an issue that does not 
presently exist, as the final rule does not in fact provide that 
modeling ``must'' be used to demonstrate attainment, but instead leaves 
for future actions the decision whether in specific cases monitoring or 
modeling or some combination of the two will best measure ambient 
SO2 concentrations. If EPA were to determine in a given 
action that the monitoring data were not sufficient to determine an 
area's attainment status, and thus that the area would have to be 
categorized as unclassifiable until sufficient monitoring data or 
modeling results were available, that designation would be the result 
of the insufficiencies in the data, not of anything that EPA has done 
in the final rule or discussed in the preamble guidance. Although it 
might seem to petitioners that monitoring, where actually conducted, 
should be inherently more accurate than modeling, this is not 
necessarily the case with respect to SO2. In fact, ``[i]n 
the past, EPA used a combination of modeling and monitoring for 
SO2 during permitting, designations and re-designations in 
recognition of the fact that a single monitoring site is generally not 
adequate to fully characterize ambient concentrations, including the 
maximum ground level concentrations, which exist around stationary 
SO2 sources.'' 75 FR at 35559. This is especially important 
because ``[t]he 1-hour NAAQS is intended to provide protection against 
short-term (5 minute to 24 hour) peak exposures.'' Id. See American 
Lung Ass'n v. EPA, 134 F. 3d at 392-93 (remanding EPA's determination 
that such exposures to SO2 do not constitute a threat to 
public health) and 75 FR at 35536 (5-10 minute SO2 exposures 
can result in adverse health effects to asthmatics).
    TCEQ's more detailed and alternative argument claiming that the 
discussion of modeling makes the form of the standard when monitoring 
is to be used unlawful must be similarly rejected, since at this point 
it is entirely

[[Page 4800]]

speculative as to whether the alleged poor ``fit'' between modeling and 
the standard will in fact occur in any specific instances. TCEQ has 
presented no facts to support a claim that the guidance discussion 
itself compels that this result has already or must inevitably occur. 
Moreover, TCEQ presents no argument as to why the form of the standard 
is inappropriate. See 75 FR at 35539-41 (discussing and justifying at 
length EPA's choice of a 99th percentile form for the new 1-hour 
standard). Like UARG and ASARCO, TCEQ appears to implicitly object to 
the fact that EPA did not in the final rule either require modeling to 
be used in all cases or promulgate specific requirements regarding 
modeling's use from which States may not deviate or to which no 
alternatives may be recommended in future implementation. Ironically, 
the petitioners thus appear to complain of the flexibility that they 
and States will have in future implementation actions to recommend data 
measurement tools that they believe will more accurately predict 
SO2 emissions concentrations. Certainly such flexibility, no 
matter how ``arduous'' it seems in application, cannot be the basis for 
a claim that a guidance discussion has any present and immediate impact 
on the promulgated NAAQS.

VI. Stay of Final Rule Issue

A. Summary of Petitioners' Requests

    Nearly all of the petitioners requested that EPA stay the 
effectiveness of the final SO2 NAAQS pending some period of 
reconsideration. UARG at one point requests a stay of the final NAAQS 
``pending completion of rulemaking,'' and at another asks for a stay 
``while EPA decides whether to reconsider key portions of the Rule,'' 
but ultimately requests a stay ``for a period of three months'' with 
the possibility of being extended. UARG at 3, 30, 32. UARG bases its 
request for a stay under CAA sections 307(d)(7)(B) and 301(a) on the 
perceived hardships that could befall pollution sources if they are 
required to achieve increasingly lower emissions rates, at increasingly 
higher costs, on the asserted restriction of State discretion resulting 
from EPA's guidance discussion, and on States' future burden of having 
to adopt and submit SIPs that show attainment via modeling. Id. at 30-
31. NEDA/CAP requests a stay of the SO2 NAAQS pending 
``agency review and action on'' its petition to ``prevent confusion and 
to conserve resources in responding to the final rule's requirements 
for initial attainment/nonattainment designations.'' NEDA/CAP at 6. 
ASARCO claims EPA ``should stay the effective date of the rule to 
provide adequate notice and opportunity to comment on the rulemaking,'' 
and therefore ``fully supports'' UARG's request for a stay. ASARCO at 
12.
    TCEQ argues EPA should stay the NAAQS under APA section 705's 
authority to postpone the effective date of action, pending judicial 
review, when an agency finds that justice so requires. TCEQ at 15. 
Under this standard, TCEQ argues, it is not required to demonstrate 
irreparable harm to support granting a stay. Id. at 15-16. North Dakota 
and South Dakota, ``because of the hardships that could result from 
implementation of EPA's 1-hour SO2 Standard in the manner 
described in the Final Rule's preamble,'' asks for a three-month stay, 
followed by an extension through the completion of rulemaking if EPA 
decides to change the rule. ND and SD at 9-10. ADEQ, in supporting the 
petitions of TCEQ and North Dakota and South Dakota in general, appears 
to also seek a stay. ADEQ at 2.

B. EPA's Response

    Consistent with our position in the litigation on the final 
SO2 Primary NAAQS in response to the motion filed by North 
Dakota to judicially stay the rule, 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 may issue a stay for up to 
three months if it grants a petition and initiates reconsideration of a 
final rule. Since we are denying the petitions to reconsider, an 
administrative stay is not warranted under that authority. In addition, 
a stay is not otherwise warranted. First, the petitioners have not made 
a strong showing of likelihood of success on the merits, for all of the 
reasons we present above for denying the petitions to reconsider. 
Second, the petitioners' speculative arguments do not show that they 
will suffer irreparable harm (as no implementation actions have yet 
been taken reflecting EPA's discussed possible approaches), and they 
fail to account for the non-binding nature of the final rule preamble's 
implementation guidance discussion, the opportunities for interested 
parties to assert their views in the future implementation actions 
about which petitioners are concerned, and EPA's stated intention to 
provide further implementation guidance. Third, petitioners' arguments 
that a stay would not harm other parties flatly ignore the harm to the 
public that would occur from delayed attainment of the SO2 
Primary NAAQS and deferred public health benefits, and they therefore 
fail to show that such a stay would not be contrary to the public 
interest.
    In addition, it is not necessary for EPA to grant a stay under CAA 
section 301(a) to carry out the Agency's functions in denying the 
petitions for reconsideration, since EPA intends to take no further 
action regarding the petitions following this denial. 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 that same day that 
the SO2 Primary NAAQS became effective. Even if EPA believed 
that an administrative stay was warranted under TCEQ's theory that the 
total absence of irreparable harm is not an impediment to granting an 
administrative stay in this matter, 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.

VII. Conclusion

    For all of the reasons discussed above, the petitions to reconsider 
the final revised SO2 Primary NAAQS are denied, as are the 
petitions for an administrative stay.

    Dated: January 14, 2011.
Lisa P. Jackson,
Administrator.
[FR Doc. 2011-1353 Filed 1-25-11; 8:45 am]
BILLING CODE 6560-50-P


