[Federal Register Volume 88, Number 139 (Friday, July 21, 2023)]
[Rules and Regulations]
[Pages 47029-47054]
[FR Doc No: 2023-15067]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 70 and 71

[EPA-HQ-OAR-2016-0186; FRL-8961-02-OAR]
RIN 2060-AV39

Removal of Title V Emergency Affirmative Defense Provisions From
State Operating Permit Programs and Federal Operating Permit Program

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is removing the
``emergency'' affirmative defense provisions from the EPA's title V
operating permit program regulations. These provisions established an
affirmative defense that sources could have asserted in enforcement
cases brought for noncompliance with technology-based emission
limitations in operating permits, provided that the exceedances
occurred due to qualifying emergency circumstances. These provisions,
which have never been required elements of state operating permit
programs, are being removed because they are inconsistent with the
EPA's interpretation of the enforcement structure of the Clean Air Act
(CAA or the Act) in light of prior court decisions from the U.S. Court
of Appeals for the D.C. Circuit. The removal of these provisions is
also consistent with other recent EPA actions involving affirmative
defenses and would harmonize the EPA's treatment of affirmative
defenses across different CAA programs. Through this document, the EPA
is also providing guidance on the implementation process resulting from

the removal of the emergency affirmative defense provisions from the
EPA's regulations, including the need for some state, local, and tribal
permitting authorities to submit program revisions to the EPA to remove
similar title V affirmative defense provisions from their EPA-approved
title V programs, and to remove similar provisions from individual
operating permits.

DATES: This final rule is effective on August 21, 2023.

ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OAR-2016-0186. All documents in the docket are
listed on the http://www.regulations.gov website. Although listed in
the index, some information is not publicly available, e.g., CBI or
other information whose 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 electronically
through http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Corey Sugerik, Office of Air Quality
Planning and Standards, Air Quality Policy Division (C504-05),
Environmental Protection Agency, Research Triangle Park, NC; telephone
number:<PHONE_NUMBER>; email address: [email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. How is this Federal Register document organized?

    The information presented in this preamble is organized as follows:

I. General Information
    A. How is this Federal Register document organized?
    B. Does this action apply to me?
    C. Where can I get a copy of this document and other related
information?
II. Background and Overview of the Final Action
III. Response to Significant Comments
    A. Affirmative Defenses and the NRDC Decision
    B. Exemptions and the Sierra Club Decision
    C. Other Legal and Policy Considerations
    D. Potential Impacts
    E. Response to Comments Outside the Scope of This Action
IV. Implementation Considerations
    A. Program Revisions
    B. Permit Revisions
V. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
    K. Congressional Review Act (CRA)
VI. Statutory Authority
VII. Judicial Review

B. Does this action apply to me?

    Entities potentially directly affected by this rulemaking include
federal, state, local, and tribal air pollution control agencies that
administer title V operating permit programs.\1\ Entities potentially
indirectly affected by this rulemaking include owners and operators of
emissions sources in all industry groups who hold or apply for title V
operating permits.
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    \1\ This preamble makes frequent use of the term ``state,''
usually meaning the state air pollution control agency that serves
as the permitting authority. The use of the term ``state'' also
applies to local, tribal, and U.S. territorial air pollution control
agencies, where applicable.
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C. Where can I get a copy of this document and other related
information?

    In addition to being available in the docket, an electronic copy of
this Federal Register document will be posted at https://www.epa.gov/title-v-operating-permits/current-regulations-and-regulatory-actions.

II. Background and Overview of the Final Action

    The EPA has promulgated permitting regulations applicable to the
operation of major and certain other sources of air pollutants under
title V of the CAA. These regulations are codified in 40 CFR parts 70
and 71, which contain the requirements for state operating permit
programs and the federal operating permit program, respectively. These
regulations contained identical provisions establishing an affirmative
defense that sources could assert in enforcement actions brought for
noncompliance with technology-based emission limitations caused by
specific emergency circumstances. These ``emergency'' provisions were
located at 40 CFR 70.6(g) and 71.6(g).
    In this action, the EPA is removing the emergency affirmative
defense provisions in 40 CFR 70.6(g) and 71.6(g) because they are
inconsistent with the EPA's current interpretation of the enforcement
structure of the CAA, in light of prior court decisions from the U.S.
Court of Appeals for the D.C. Circuit--primarily the court's 2014
decision in NRDC v. EPA, 749 F.3d 1055 (D.C. Cir. 2014). The removal of
these provisions is also consistent with other recent EPA actions
involving affirmative defenses \2\ and will harmonize the EPA's
treatment of affirmative defenses across different CAA programs. The
EPA previously provided background on the title V emergency provisions
and articulated its justification for this action in the preamble to
the 2016 and 2022 proposed rules preceding this final
rule.3 4 Section III. of this document responds to
significant comments we received on those proposals and provides
additional information in support of this final rule.
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    \2\ In newly issued and revised New Source Performance Standards
(NSPS), emission guidelines for existing sources, and NESHAP
regulations, the EPA has either omitted new affirmative defense
provisions or removed existing affirmative defense provisions. See,
e.g., National Emission Standards for Hazardous Air Pollutants for
the Portland Cement Manufacturing Industry and Standards of
Performance for Portland Cement Plants; Final Rule, 80 FR 44771
(July 27, 2015); National Emission Standards for Hazardous Air
Pollutants for Major Sources: Industrial, Commercial, and
Institutional Boilers and Process Heaters; Final Rule, 80 FR 72789
(November 20, 2015); Standards of Performance for New Stationary
Sources and Emission Guidelines for Existing Sources: Commercial and
Industrial Solid Waste Incineration Units; Final Rule, 81 FR 40956
(June 23, 2016).
    \3\ See Removal of Title V Emergency Affirmative Defense
Provisions From State Operating Permit Programs and Federal
Operating Permit Program, Proposed Rule, 81 FR 38645 (June 14,
2016); Removal of Title V Emergency Affirmative Defense Provisions
From State Operating Permit Programs and the Federal Operating
Permit Program, Proposed Rule, 87 FR 19042 (April 1, 2022).
    \4\ Docket No. EPA-HQ-OAR-2016-0186 comprises all supporting
documents and public comments for both the 2016 and 2022 proposals.
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    As a consequence of the EPA's action to remove these provisions
from 40 CFR 70.6(g), it will be necessary for any states that have
adopted similar affirmative defense provisions in their part 70
operating permit programs to revise their part 70 programs to remove
these provisions. In addition, individual operating permits that
contain title V affirmative defenses based on 40 CFR 70.6(g) or similar
state regulations will eventually need to be revised. The EPA discussed
its expectations concerning how states will implement this rule in
section V. of the preamble to the 2016 proposed rule and also requested

comments on some of the aspects discussed. Additional information
regarding these implementation considerations and the EPA's response to
relevant comments received on these issues are included in section IV.
of this document.
    EPA expects that program revisions to remove the title V emergency
defense provisions from state operating permit programs will include,
at minimum: (1) a redline document identifying the state's proposed
revision to its part 70 program rules; (2) a brief statement of the
legal authority authorizing the revision; and (3) a schedule and
description of the state's plans to remove affirmative defense
provisions from individual operating permits. The EPA encourages states
to consult with their respective EPA regional offices on the specific
contents of their revision submittal packages.
    In general, any impermissible affirmative defense provisions within
individual operating permits that are based on a title V authority and
that apply to federally-enforceable requirements will need to be
removed. As explained in the 2016 proposal, the EPA expects that any
necessary permit changes should occur in the ordinary course of
business, such as during periodic permit renewals or revisions. At the
latest, states would be expected to remove affirmative defense
provisions from individual permits by the next periodic permit renewal
that occurs following either (1) the effective date of this rule (for
permit terms based on 40 CFR 70.6(g) or 71.6(g)) or (2) the EPA's
approval of state program revisions (for permit terms based on a state
affirmative defense provision).

III. Response to Significant Comments

    This section contains the EPA's response to significant comments
regarding the EPA's proposed action to remove 40 CFR 70.6(g) and
71.6(g) and provides the EPA's justification for this final action.
Comments and the EPA's responses are divided into four general topic
areas: section III.A. of this document discusses the legal basis for
this action in light of the NRDC decision; section III.B. discusses
issues related to exemptions from emission limitations and the D.C.
Circuit's 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir.
2008); section III.C. discusses other legal and policy considerations;
and section III.D. discusses various issues involving the consequences
of removing the title V emergency affirmative defense provisions from
operating permit programs, focusing primarily on the impact on sources.

A. Affirmative Defenses and the NRDC Decision

    The following subsections address comments received concerning the
NRDC decision and the EPA's legal basis for this action. Subsections
III.A.1. and III.A.2. of this document address general comments either
supporting or opposing the EPA's interpretation of the NRDC decision.
Subsection III.A.3. addresses specific comments concerning the extent
to which the NRDC decision should apply beyond the context of citizen-
suit enforcement under CAA section 304, and how the decision should
inform the EPA's treatment of affirmative defenses in the context of
EPA-initiated judicial enforcement and administrative penalty actions
under CAA sections 113(b) and (d). Specific comments that discuss the
relationship between the NRDC decision and prior case law are presented
in section III.C.2. of this document.
1. Support for the EPA's Interpretation of the CAA's Enforcement
Structure in Light of the NRDC Decision
    Comment: Multiple environmental and state commenters supported the
EPA's view that, in light of NRDC, the title V emergency affirmative
defense provisions should be removed because they impermissibly limit
the authority of courts to decide appropriate penalties in private
civil suits. Some commenters claimed that the EPA lacks the authority
to create such provisions. Other state and industry commenters
acknowledged that the NRDC decision limits the EPA's discretion to
retain affirmative defense provisions, either altogether or in certain
contexts. Commenters argued that when Congress wanted to limit the
authority of courts, to allow an affirmative defense or to permit an
extrajudicial entity to modify penalties, it did so expressly, citing
CAA sections 113(e)(1), 113(c)(5)(C)-(D), and 113(d)(2)(B).
    Some commenters asserted that the NRDC decision applies beyond the
specific context of CAA section 112 standards because the court's
rationale was based on CAA sections 113 and 304, not CAA section 112.
Therefore, commenters concluded that the prohibition on affirmative
defenses applies to any citizen-enforceable emission standards or
limitations under the Act. Commenters claimed that NRDC is applicable
to the title V emergency affirmative defense provisions because, like
the hazardous air pollution standards at issue in NRDC, all other
emission standards contained in title V operating permits are
enforceable under CAA section 304. Some commenters further asserted
that the fundamental principles underlying the NRDC decision with
respect to affirmative defenses were reinforced by the D.C. Circuit's
2016 decision in U.S. Sugar v. EPA.\5\
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    \5\ U.S. Sugar Corp. v. EPA, 830 F.3d 579 (D.C. Cir. 2016),
amended on rehearing on unrelated grounds, U.S. Sugar Corp v. EPA,
844 F.3d 268 (D.C. Cir. 2016).
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    Response: The EPA generally agrees with commenters supporting the
legal basis for this action to remove the emergency affirmative defense
provisions from the EPA's title V regulations. The EPA previously
explained its legal rationale for this action in the 2016 and 2022
proposed rules.\6\ Here, the EPA reiterates some of the primary legal
principles guiding this current action.
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    \6\ See 81 FR 38649. As noted in the 2016 and 2022 proposals,
the EPA has also previously explained its interpretation of the CAA
in light of the NRDC decision at great length in multiple other
documents, including documents supporting the EPA's 2015 SSM SIP
Action. See State Implementation Plans: Response to Petition for
Rulemaking; Findings of Substantial Inadequacy; and SIP Calls To
Amend Provisions Applying to Excess Emissions During Periods of
Startup, Shutdown and Malfunction; Supplemental Proposal To Address
Affirmative Defense Provisions in States Included in the Petition
for Rulemaking and in Additional States, Supplemental Notice of
Proposed Rulemaking, 79 FR 55919, 55929 (September 17, 2014) (SSM
SIP Action Supplemental Proposal); State Implementation Plans:
Response to Petition for Rulemaking; Restatement and Update of EPA's
SSM Policy Applicable to SIPs; Findings of Substantial Inadequacy;
SIP Calls To Amend Provisions Applying to Excess Emissions During
Periods of Startup, Shutdown and Malfunction, Final Action, 80 FR
33839, 33851 (June 12, 2015) (SSM SIP Action); and Memorandum,
Withdrawal of the October 9, 2020, Memorandum Addressing Startup,
Shutdown, and Malfunctions in State Implementation Plans and
Implementation of the Prior Policy, 3-4 (September 30, 2021),
available at https://www.epa.gov/system/files/documents/2021-09/oar-21-000-6324.pdf (September 2021 SSM SIP Memo).
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    The EPA's current interpretation of the CAA with respect to
affirmative defenses is informed by the D.C. Circuit's NRDC decision.
In NRDC, the D.C. Circuit vacated affirmative defense provisions
contained in the EPA's National Emission Standards for Hazardous Air
Pollutants (NESHAP) for the portland cement industry, promulgated under
CAA section 112. The D.C. Circuit concluded that the EPA lacked the
authority to create these affirmative defense provisions because they
contradicted fundamental requirements of the Act concerning the
authority of courts to decide whether to assess civil penalties in CAA
enforcement suits. Importantly, the court's decision did not turn upon
any specific provisions of CAA section 112, but rather on the
provisions of CAA sections 113 and 304. These provisions

pertain to enforcement of a wide variety of CAA requirements beyond
section 112 standards, including enforcement of emission limits
contained in title V permits. Thus, the mere fact that the court
addressed the legality of an affirmative defense provision in the
context of a section 112 NESHAP does not mean that the court's
interpretation of sections 113 and 304 does not also apply more
broadly. To the contrary, the EPA sees no reason why the logic of the
court concerning sections 113 and 304 would not apply to the title V
emergency affirmative defense provisions, as well.
    Notably, in 2016, the D.C. Circuit reaffirmed its NRDC opinion
concerning affirmative defenses. In U.S. Sugar, the D.C. Circuit
addressed various challenges to rules promulgated in 2011, including
challenges urging that--in the absence of affirmative defenses--the EPA
was required to address periods of malfunction in setting the
applicable standards. Discussing NRDC, the U.S. Sugar opinion stated
that the affirmative defense provision at issue in the NRDC case was
``an impermissible intrusion on the judiciary's role.'' \7\ The fact
that the title V emergency affirmative defenses arguably apply more
broadly (i.e., to potentially numerous technology-based emission limits
developed under multiple CAA program areas) than the affirmative
defense at issue in NRDC potentially makes it even more intrusive on
the judiciary's role.
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    \7\ See U.S. Sugar, 830 F.3d at 607.
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    In light of the NRDC decision and the EPA's reevaluation of the
CAA, the EPA interprets the enforcement provisions in sections 113 and
304 of the CAA to preclude affirmative defense provisions that would
operate to limit a court's authority or discretion to determine the
appropriate remedy in an enforcement action. Section 304(a) grants the
federal district courts jurisdiction to determine liability and to
impose penalties in enforcement suits brought by citizens. Similarly,
section 113(b) grants the federal district courts jurisdiction, in
enforcement actions brought by the U.S. Department of Justice (DOJ) on
behalf of the EPA, to determine liability and to impose remedies of
various kinds, including injunctive relief and monetary penalties.
These grants of jurisdiction come directly from Congress, and the EPA
is not authorized to alter or eliminate this authority. With respect to
monetary penalties, CAA section 113(e) lists various factors that
courts and the EPA shall consider in the event of judicial or
administrative enforcement for violations of CAA requirements,
including title V permit conditions. Because Congress has already given
federal courts the authority to determine what penalties are
appropriate in the event of judicial enforcement for a violation of a
title V permit provision, neither the EPA nor states should be able to
alter or eliminate that authority by superimposing restrictions on the
authority and discretion granted by Congress to the courts. Affirmative
defense provisions by their nature limit or eliminate the authority of
federal courts to determine liability or to impose remedies through
considerations that differ from the explicit grants of authority in
section 113(b) and section 113(e). Therefore, these provisions are not
appropriate under the CAA, no matter what type of event they apply to,
what criteria they contain, or what forms of remedy they purport to
limit or eliminate. The emergency affirmative defense provisions that
the EPA is removing from 40 CFR 70.6(g) and 71.6(g) purported to
interfere with the authority of the courts to determine whether and to
what extent penalties or other remedies were appropriate in judicial
enforcement actions, conflicted with the holding of NRDC, and were
contrary to the enforcement structure of the CAA. Thus, the EPA has
determined that these provisions should be removed from the EPA's
regulations.
    Section IV.A. of this document contains additional information
concerning the need for states to submit program revisions to remove
similar title V affirmative defense provisions from EPA-approved state
operating permit programs, and to remove similar provisions from
individual operating permits.
2. Comments Suggesting That the NRDC Case Is a Narrow Decision That the
EPA Is Incorrectly Extending or Misapplying
    Comment: Some commenters stated that the D.C. Circuit's decision in
NRDC v. EPA was limited to the particular facts or circumstances of
that case and that the EPA's reliance on the decision to support
removal of the title V emergency affirmative defense provisions is an
incorrect extension or misapplication of the decision. Commenters
generally claimed that the EPA should not apply the NRDC court's ruling
to every corner of the CAA, including to the title V affirmative
defense provisions within the EPA's regulations and state operating
permit programs. Some commenters stated that the NRDC decision only
invalidated an affirmative defense associated with a NESHAP issued in
accordance with CAA section 112, and that the decision should be
limited to those standards (or, even, to the specific standards for
portland cement plants subject to that litigation). Commenters alleged
that the D.C. Circuit provided no language to broaden its ruling. Some
commenters focused on the specific statutory mandates involved in
establishing section 112 standards. One commenter alleged that the D.C.
Circuit held that once a section 112 standard is promulgated and
established for all operating modes, no ``gap'' remains for the EPA to
create an affirmative defense.
    Other commenters focused on the differences between title V permits
and the section 112 standards that the NRDC court considered. These
commenters explained that title V permits contain numerous different
underlying standards applicable to a source (such as standards
developed under a State Implementation Plan (SIP) or under New Source
Review Programs), as well as additional procedural and monitoring,
reporting, and recordkeeping requirements. Thus, one commenter asserted
that enforcement of title V permit requirements differs from
enforcement of specific section 112 emission limits, and that the D.C.
Circuit's logic prohibiting affirmative defenses does not apply to
other types of applicable requirements in a title V permit, including
substantive standards as well as administrative or procedural
requirements.
    Some commenters attempted to distinguish the title V emergency
affirmative defense, which at least one commenter characterized as a
defense to ``liability'' or ``noncompliance,'' from the affirmative
defense to ``civil penalties'' at issue in the NRDC case. One commenter
claimed that the NRDC decision was based on the assumption that excess
emissions automatically result in a violation of a section 112
standard, and therefore that the D.C. Circuit only addressed how
affirmative defense provisions affect a court's authority to determine
appropriate remedies after an actionable violation has been identified.
Multiple commenters asserted that neither CAA section 113 nor the NRDC
case speak to provisions that define when a violation has occurred.
Some commenters also asserted that the NRDC decision involved an
affirmative defense for malfunctions, not emergencies, and concluded
that the EPA should not apply the decision to the title V emergency
affirmative defense because malfunctions are not similar in nature to
emergencies.
    Some commenters also claimed more generally that the title V
affirmative defense provisions do not impair a court's ability to
decide whether a source has met its burden of

demonstrating that an emergency has occurred and whether civil
penalties are appropriate. Other commenters discussed the breadth of
the NRDC case with respect to SIP provisions. Commenters asserted that
the D.C. Circuit did not opine on the authority of the EPA or states to
provide relief from noncompliance with technology-based SIP standards
that are incorporated into title V operating permits. Commenters also
claimed that the D.C. Circuit expressly reserved judgment concerning
the validity of such defenses in SIPs,\8\ and that states have
discretion under the CAA to include affirmative defense provisions in
their SIPs. These commenters attempted to distinguish SIPs from the
section 112 standards at issue in the NRDC case. Multiple commenters
also incorporated in their comment submissions various attachments
related to the Startup, Shutdown, and Malfunction (SSM) SIP Action,\9\
including comments submitted on the initial and supplemental SSM SIP
Call proposals \10\ as well as briefs filed in the ongoing SSM SIP
Action litigation.\11\ Portions of these attachments addressed the
EPA's interpretation of the NRDC case.
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    \8\ Commenters cited NRDC, 749 F.3d at 1064 n.2.
    \9\ SSM SIP Action, 80 FR 33840.
    \10\ State Implementation Plans: Response to Petition for
Rulemaking; Findings of Substantial Inadequacy; and SIP Calls To
Amend Provisions Applying to Excess Emissions During Periods of
Startup, Shutdown, and Malfunction; Proposed Rule, 78 FR 12460
(February 22, 2013); SSM SIP Action Supplemental Proposal, 79 FR
55919.
    \11\ Environmental Committee of the Florida Electric Power
Coordinating Group, Inc. v. EPA, No. 15-1239 (D.C. Cir.) (SSM SIP
Action litigation).
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    Response: The EPA disagrees with commenters' assertions that the
logic of the NRDC case was restricted to the context of section 112
standards, or to a single NESHAP standard. Most of these comments do
not address the fundamental legal principles upon which the D.C.
Circuit based its decision, or the EPA's explanation of these
principles. Contrary to what some commenters suggest, the NRDC decision
was not based on any statutory mandates specific to promulgating CAA
section 112 standards. Instead, the decision was based on CAA sections
113 and 304, which apply broadly to the enforcement of a wide range of
CAA requirements, including SIP requirements. Thus, any differences
between section 112 standards and other standards contained in title V
permits (or, for example, the difference between malfunctions and
emergencies) are irrelevant to the legal principles upon which the NRDC
decision was based, and which apply equally well to the EPA's title V
regulations in 40 CFR 70.6(g) and 71.6(g), as discussed in the
preceding subsection.
    The EPA also disagrees that NRDC is distinguishable from the
current action due to any functional differences between the
affirmative defense at issue in NRDC, which some commenters
characterized as a defense to a claim for civil penalties for
violations, and the title V emergency affirmative defense, which
commenters characterized as a defense to an action brought for
noncompliance. Both the title V affirmative defense and the portland
cement NESHAP malfunction affirmative defense (originally located at 40
CFR 63.1344) established an affirmative defense that a source could
assert in actions brought under CAA sections 113 and 304, after an
enforcement action had been initiated for an alleged violation.\12\
Both affirmative defense provisions functioned in the same manner. The
fact that the portland cement defense was confined to enforcement
actions for penalties, whereas the title V provisions do not on their
face contain such an explicit restriction and could potentially be read
more broadly, is irrelevant to the fact that both provisions purported
to interfere with the authority of courts to determine whether and to
what extent relief is appropriate in a given case, including relief
from penalties. Moreover, CAA section 304(a), upon which the D.C.
Circuit relied, is not restricted to monetary penalties. The EPA has
previously explained its position that affirmative defenses are
inappropriate regardless of what type of event they apply to, what
criteria they contain, or what forms of remedy they purport to limit or
eliminate. The EPA also notes that the title V emergency affirmative
defense provisions were explicitly restricted to noncompliance with
technology-based emission limits (such as emission limits derived from
a NESHAP similar to the ones the D.C. Circuit invalidated) and were
never available as a defense in an enforcement case for violations of
other types of title V permit requirements, contrary to some
commenters' assertions.
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    \12\ To the extent that commenters argue that the title V
affirmative defenses function to define when a violation has
occurred, these comments are addressed further in section III.B.1.
of this document.
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    Finally, the EPA disagrees with commenters' claims that the title V
affirmative defense provisions would not impair a court's ability to
decide whether civil penalties are appropriate because a source
attempting to invoke the title V emergency affirmative defense would
have the burden to prove that an emergency occurred and other
demonstration requirements had been met. The affirmative defense
provision formerly in the portland cement NESHAP was similarly
structured, and the D.C. Circuit nonetheless found that those
provisions impermissibly intruded into the judiciary's role to
determine whether penalties are appropriate. Any comments challenging
the holding of the D.C. Circuit in NRDC are beyond the scope of this
rulemaking. To the extent that commenters suggested that a title V
affirmative defense provision could be appropriate with respect to
certain technology-based SIP requirements contained in a title V
permit, the EPA disagrees. For the reasons previously discussed,
affirmative defense provisions in title V permits are not appropriate
with respect to any federally-enforceable requirements. To the extent
that commenters discussed the relationship between the NRDC and Sierra
Club cases and affirmative defense provisions contained within SIPs,
and to the extent that commenters incorporated comments or briefs
relevant to the SSM SIP Action but did not specifically explain how
those comments were pertinent to the EPA's proposal to eliminate the
title V emergency affirmative defense provisions, such comments are
beyond the scope of this current rulemaking. Moreover, the EPA has
previously responded to those comments and legal briefs in the
appropriate venues.\13\ To the extent that comments addressed issues
relevant to this action, the EPA is responding to these comments in
this document.
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    \13\ See SSM SIP Action, 80 FR 33840, 33852 (noting that
``[s]tates have great discretion in how to devise SIP provisions,
but they do not have discretion to create provisions that contradict
fundamental legal requirements of the CAA'' and that ``[t]he
jurisdiction of federal courts to determine liability and to impose
statutory remedies for violations of SIP emission limitations is one
such fundamental requirement''); Initial Brief of Respondent EPA,
SSM SIP Action Litigation (filed July 26, 2016).
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3. The NRDC Case As It Applies Beyond Citizen-Suit Enforcement Under
CAA Section 304(a)
    Comment: Many commenters argued that the NRDC decision only
invalidated affirmative defenses that could be asserted in citizen
suits brought under CAA section 304 in federal court. These commenters
asserted that the NRDC case does not require the EPA to remove
affirmative defenses with respect to either: (1) EPA-initiated civil
judicial enforcement actions under section 113(b); or (2)
administrative penalty actions brought under section 113(d). Many of
these commenters recommended that instead of entirely

removing the title V emergency affirmative defense provisions, the EPA
should amend the provisions to clarify that they do not apply to any
enforcement actions based on section 304, but only to actions based on
sections 113(b) and (d).
    First, regarding EPA-initiated enforcement under section 113(b),
some commenters acknowledged the EPA's position (as explained in the
2016 proposed rule) that, because both sections 304 and 113(b) vest
federal district courts with the ability to determine liability and
assess penalties, the EPA's hands are tied with respect to its own
civil enforcement. One commenter noted that the NRDC case did not
directly speak to enforcement actions brought by the EPA under section
113(b). Other commenters claimed that section 113(b) does nothing to
impede the EPA's ability to define the circumstances under which it is
``appropriate'' to initiate an enforcement action, and that this would
not interfere with the authority of a court to determine liability and
assess penalties in an eventual enforcement action. Some commenters
suggested that the EPA could use the affirmative defense to define by
rule when it would be appropriate to commence an enforcement action,
and others noted that the practical effect of the defense is to define
when the EPA will exercise its enforcement discretion to initiate an
enforcement action in the courts.
    Second, regarding the EPA's authority to assess administrative
penalties under section 113(d), commenters cited language from the NRDC
decision, wherein the D.C. Circuit noted that, although the EPA did not
have discretion to determine whether civil penalties should be imposed
by a court, the agency had discretion to determine whether to assess
administrative penalties under section 113(d).\14\ Various commenters
similarly alleged that because CAA section 113(d) explicitly gives the
EPA the authority to modify penalties, it therefore allows the EPA to
establish an affirmative defense in the context of administrative
enforcement. Some commenters claimed that retaining the title V
affirmative defense for administrative enforcement is especially
important because most penalties related to emission exceedances are
imposed through administrative penalties sought by the agency, not as a
result of citizen suits in federal court. Finally, some commenters
suggested that the EPA could define when it would be appropriate to
assess administrative penalties.
---------------------------------------------------------------------------

    \14\ See NRDC, 749 F.3d at 1063.
---------------------------------------------------------------------------

    Commenters also made similar arguments with respect to the ability
of states to determine when it would be appropriate to pursue
enforcement action, whether through the courts or with respect to
administrative penalties.
    Response: The EPA disagrees with the claim that it would be
appropriate to retain the title V affirmative defense provisions for
use in EPA-initiated judicial enforcement or administrative penalty
actions. First, as explained previously and as acknowledged by
commenters, the logic of the NRDC case applies not only to citizen-suit
actions under section 304(a), but also to judicial enforcement actions
initiated by DOJ on behalf of the EPA pursuant to section 113(b). Like
section 304(a), section 113(b) involves enforcement actions that are
ultimately brought before federal courts. Therefore, any affirmative
defense that could be asserted in an enforcement proceeding brought
under section 113(b) would similarly infringe on the authority of
courts to determine appropriate penalties. Regarding suggestions that
the EPA could treat the affirmative defense as establishing criteria
defining whether the EPA considers it ``appropriate'' to commence an
enforcement action under section 113(b), the EPA finds that this is not
necessary or appropriate. For the reasons provided in section III.D.2.
of this document, the EPA has decided not to explicitly codify such an
``enforcement discretion'' type provision.
    Second, the EPA acknowledges that NRDC does not address the EPA's
authority to establish an affirmative defense to CAA section 113(d)
administrative actions. However, such an affirmative defense is not
necessary. As discussed further in section III.D.2., if a source
believes it is unable to comply with emissions standards as a result of
an emergency, the EPA may use its case-by-case enforcement discretion
to determine whether to initiate enforcement, as appropriate. Further,
as the D.C. Circuit recognized, in an EPA or citizen enforcement
action, the court has the discretion to consider any defense raised and
determine whether penalties are appropriate.\15\ The same is true for
EPA administrative actions. Moreover, assessment of penalties for
violations in administrative proceedings and judicial proceedings
should generally be consistent. Cf. CAA section 113(e), 42 U.S.C.
7413(e) (requiring both the Administrator of the EPA and the court to
take specified criteria into account when assessing penalties). The EPA
has previously explained this approach in various rules developed under
CAA sections 111, 112, and 129.\16\
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    \15\ See NRDC, 749 F.3d at 1064; see also U.S. Sugar, 830 F.3d
at 609. (``[Sources] can argue that penalties should not be assessed
because of an unavoidable malfunction'' and courts ``should not
hesitate to exercise their judicial authority to craft appropriate
civil remedies in the case of emissions exceedances caused by
unavoidable malfunctions.'').
    \16\ See, e.g., National Emission Standards for Hazardous Air
Pollutants Residual Risk and Technology Review for Flexible
Polyurethane Foam Production; Final Rule, 79 FR 48073, 48082 n.3
(August 15, 2014); Oil and Natural Gas Sector: Reconsideration of
Additional Provisions of New Source Performance Standards; Final
Rule, 79 FR 79017, 79024 n.3 (December 31, 2014); National Emission
Standards for Hazardous Air Pollutants: Polyvinyl Chloride and
Copolymers Production Reconsideration; Proposed Rule, 85 FR 71490
n.16 (November 9, 2020).
---------------------------------------------------------------------------

    Section IV.A.3. of this document discusses similar issues regarding
how states may be able to implement this rule by retaining or
developing similar provisions that apply in the limited context of
state-initiated administrative enforcement actions or judicial
enforcement in state courts.

B. Exemptions and the Sierra Club Decision

    In the 2016 proposed rule, the EPA noted that the D.C. Circuit in
Sierra Club vacated an EPA rule that exempted sources from otherwise
applicable emissions standards during periods of SSM because the SSM
exemption violated the CAA requirement that such standards apply
continuously. The EPA stated that, although the title V emergency
affirmative defenses were not exemptions, if they were to be construed
or treated as exemptions, they would run afoul of Sierra Club and also
should be removed for that reason. The EPA received various comments
relating to these issues.
1. Comments Suggesting That the Title V Emergency Provisions Create an
Exemption to Emission Limits or Define Whether a Violation Has Occurred
    Comment: Commenters presented differing perspectives on how the
title V emergency affirmative defense provisions function. The majority
of commenters addressing this topic supported the EPA's position that
the title V affirmative defense provisions, by their terms, clearly
function as an affirmative defense, rather than as exemptions or
provisions that define when a violation occurs. Commenters supporting
this perspective explained that applicable emission limits would still
apply during an emergency, and exceedances would still constitute a

violation, but sources could later assert the affirmative defense in an
effort to demonstrate to either the agency or a judge that, despite a
violation of the applicable requirement, there are valid reasons to
excuse the source from some or all penalties associated with the
violation. Another commenter noted the very strict conditions that a
source attempting to claim the affirmative defense for an emergency
would have to comply with and document in order to be eligible for the
affirmative defense. Similarly, commenters acknowledged that asserting
this defense would not automatically mean it was granted.
    However, other commenters suggested that the affirmative defense
provisions functionally serve as exemptions to applicable emission
limits or define when a violation of an emission limit has occurred.
For example, one commenter claimed that the title V affirmative defense
provisions operate as an exemption, whereby no restriction or emission
limit would exist in specific emergency circumstances. One commenter
suggested that the affirmative defenses found in 40 CFR 70.6(g) are an
affirmative defense to liability rather than an affirmative defense for
the reduction of penalties, which the commenter claims was considered
in NRDC. Other commenters claimed that the title V affirmative defense
essentially provides criteria for the EPA, the state, or a court to
consider when deciding whether excess emissions trigger a violation in
the first instance, and these commenters attempted to distinguish the
title V affirmative defense from the section 112 affirmative defense at
issue in the NRDC decision. Environmental commenters stated that the
emergency provisions could be interpreted to mean that, when their
terms are met, a source did not violate the relevant emission
limitation, thereby effectively providing an exemption. Environmental
commenters also argued that this type of functional exemption would be
illegal.
    Finally, one commenter suggested that the EPA convert the emergency
affirmative defense provisions into a narrowly tailored exemption from
technology-based standards. The commenter asserted that this approach
would be within the EPA's authority, and that an exemption would
provide more consistency than the use of enforcement discretion alone.
    Response: The EPA agrees with the majority of commenters that
acknowledged that the title V emergency affirmative defense provisions
did not create exemptions or otherwise define whether a violation has
occurred, as stated in the proposal.\17\ The provisions being removed
through this action, found at 40 CFR 70.6(g)(2) and 71.6(g)(3) state,
in part, ``An emergency constitutes an affirmative defense to an action
brought for noncompliance with . . . technology-based emission
limitations.'' By their terms, these provisions explicitly purported to
establish an affirmative defense to an enforcement action, not an
exemption. Moreover, these provisions purported to establish an
affirmative defense to an action brought for noncompliance with certain
emission limits. So, before the defense would apply, alleged
noncompliance with an emissions limitation would have already occurred,
and an enforcement action (administrative or judicial) would have been
brought because of such noncompliance. The title V affirmative
defenses, like the affirmative defense provisions at issue in the NRDC
case, were thus based on the establishment of an alleged violation of
permitted emission limits in the first instance. Moreover, it would not
have been the burden of the party bringing an action for noncompliance
to negate any claimed emergency ``exemption'' to an otherwise
applicable emission limit. Rather, it would clearly have been the
source's burden in defending against such an action to properly assert
and prove all the elements of the emergency affirmative defense.\18\
The result of a successfully pled affirmative defense would be to
provide the decision maker in an enforcement case with reasons why,
despite violations of an emission limit, the source should not be held
liable and assessed penalties (or potentially other forms of relief)
for such noncompliance. Therefore, the EPA believes that the title V
emergency affirmative defense provisions were not intended and should
not be interpreted to function as an exemption or to otherwise define
when a violation has occurred.
---------------------------------------------------------------------------

    \17\ See 81 FR 38645, 38651.
    \18\ See 40 CFR 70.6(g)(4) (the ``permittee . . . has the burden
of proof'').
---------------------------------------------------------------------------

    To the extent that the affirmative defense provisions could have
been interpreted to provide an exemption or define whether a violation
has occurred, the EPA reiterates that such an exemption would be
impermissible under the EPA's interpretation of the CAA and in light of
Sierra Club. Some commenters suggested that the EPA should interpret
the affirmative defense to function as an affirmative defense to
liability or to define whether the emission limitation applies and thus
whether there is a ``violation.'' But, if there is no ``violation''
when certain criteria or conditions for an affirmative defense are met,
then there is, in effect, no emission limitation that applies when the
criteria or conditions are met, and the affirmative defense would
operate to create an exemption from the emission limitation. As
discussed in the following subsection, and based on the EPA's
interpretation of the Sierra Club decision, this would violate the
basic CAA principle that emission limitations must apply continuously
and cannot contain exemptions, conditional or otherwise. For the same
reasons, it is not appropriate to convert the title V emergency
affirmative defense provisions into an exemption, as suggested by a
commenter.
2. Comments Interpreting the Sierra Club Case With Respect to
Exemptions From Emission Limitations
    Comment: Commenters presented differing views on the EPA's
interpretation of Sierra Club. Environmental commenters supported the
EPA's conclusion that exemptions from emission limitations are
unlawful, and that, to the extent that the title V emergency
affirmative defense provisions could be interpreted as providing for an
exemption, those provisions would be unlawful. Commenters noted that in
the Sierra Club case, the D.C. Circuit held that sections 112 and
302(k), read together, require that there must be continuous section
112-compliant standards. Commenters claimed that the statutory terms
``emission standard'' and ``emission limitation'' mean the same thing,
citing CAA section 302(k). Therefore, commenters asserted the court's
holding in Sierra Club also applies to the emission limitations
affected by the title V affirmative defenses. Environmental commenters
further asserted that the fundamental principles underlying the Sierra
Club decision with respect to exemptions were reinforced by the D.C.
Circuit's U.S. Sugar decision.
    However, a number of industry commenters challenged the EPA's
interpretation of the Sierra Club case, arguing generally that the case
has limited applicability beyond the context of section 112 standards.
Some commenters asserted that Sierra Club is not relevant to the
current rulemaking because the case was anchored to the unique language
of CAA section 112 and only addressed exemptions under CAA section 112,
rather than regulations in operating permit programs, SIP requirements,
or New Source Performance Standards (NSPS) regulations. One commenter
argued that because the Sierra Club decision was

limited to section 112 standards, the decision could at most be read to
prohibit title V provisions excusing noncompliance with an underlying
NESHAP provision.
    Other commenters asserted that requirements that limit emissions on
a continuous basis do not have to impose the same limitation at all
times, and that the form of the limitation does not always have to be
the same. For example, commenters noted that CAA section 302(k)
includes design, equipment, work practice, and operational standards,
which could apply during periods of operation not covered by a
numerical emissions limitation. These commenters claim that the Sierra
Club case did not approach the question of whether these different
types of standards would be acceptable. One commenter also asserted
that the emergency affirmative defense is not an exemption from
continuously applicable emission limits.
    Response: As discussed in the preceding subsection, the title V
emergency affirmative defense provisions should not be interpreted to
provide an exemption to emission limits or otherwise define when a
violation of an emission limitation has occurred. However, as noted in
the proposal, to the extent that the title V provisions could be
interpreted as providing such an exemption, this would run afoul of the
CAA requirement that emission limitations be continuous. See CAA
section 302(k), 42 U.S.C. 7602(k). The EPA disagrees with commenters'
assertions that the Sierra Club court's reasoning does not apply beyond
section 112 standards. As the EPA has explained in depth in other
documents, the same logic prohibiting exemptions from NESHAP emission
limits applies to other emission limitations subject to the definition
of ``emission limitation'' within section 302(k), including emission
limits contained within a source's title V permit.\19\ Finally,
comments on whether it is appropriate to impose different types of
emission limitations during different modes of operation may be
relevant to standard-setting or other proceedings where such
limitations are established, but these comments are not material to
this rulemaking to remove the title V emergency affirmative defense
provisions.
---------------------------------------------------------------------------

    \19\ See, e.g., SSM SIP Action, 80 FR 33892 (``Since the 2008
D.C. Circuit decision in Sierra Club v. Johnson, however, it has
been clear that NSPS and NESHAP standards themselves cannot contain
such exemptions. The reasoning of the court was that exemptions for
SSM events are impermissible because they contradict the requirement
that emission limitations be `continuous' in accordance with the
definition of that term in section 302(k). Although the court
evaluated this issue in the context of EPA regulations under section
112, the EPA believes that this same logic extends to SIP provisions
under section 110, which similarly must contain emission limitations
as defined in the CAA. Section 110(a)(2)(A) requires states to have
emission limitations in their SIPs to meet other CAA requirements,
and any such emission limitations would similarly be subject to the
definition of that term in section 302(k).''); see also id. at
33862.
---------------------------------------------------------------------------

C. Other Legal and Policy Considerations

    This section addresses comments involving other legal and policy
considerations related to the EPA's removal of the title V emergency
affirmative defense provisions.
1. Ongoing SSM SIP Action Litigation
    Comment: Some state and industry commenters urged the EPA to delay
finalizing this action until the ongoing SSM SIP Action litigation
concludes. These commenters claimed that the EPA's rationale underlying
this title V action depends on the same core legal issues involving the
EPA's interpretation of the NRDC and Sierra Club cases, which the
commenters claimed is currently under judicial review in the SSM SIP
Action litigation. One commenter further asserted that an adverse
ruling in the SSM SIP Action litigation would be dispositive of the
issues involved here.
    Response: The EPA disagrees with the commenters' suggestion to
delay this final action. The EPA has no reason to delay moving forward
with the removal of affirmative defense provisions from various CAA
program areas, including title V, solely because litigants have
challenged the SSM SIP Action. The EPA is confident of the strong legal
and policy bases for this current action, as well as prior actions in
the SSM SIP Action and numerous regulations promulgated under CAA
sections 111, 112, and 129 that also address affirmative defense
provisions. In fact, the EPA's interpretation of the CAA and its
application of relevant court decisions was upheld by the D.C.
Circuit.\20\ The EPA also disagrees with commenters' assertions that an
adverse decision with respect to the SSM SIP Action would necessarily
undermine the legal justification for this rule, because the SSM SIP
Action litigation could be decided on procedural or substantive grounds
that would not be determinative for this action. For example, the
ongoing SSM SIP Action litigation involves many issues that are
unrelated to this current rulemaking.\21\
---------------------------------------------------------------------------

    \20\ Specifically, the EPA's approach to addressing malfunction
emissions in section 112 rules for major boilers and area boilers
and section 111 and 129 rules for commercial and industrial solid
waste incinerators was upheld by the D.C. Circuit in U.S. Sugar.
    \21\ For example, briefs filed in the SSM SIP Action litigation
allege, among other things, that the EPA failed to make the showing
required to issue a SIP call, which is a procedure specific to CAA
section 110. See Brief of Industry Petitioners, SSM SIP Action
Litigation (filed March 16, 2016).
---------------------------------------------------------------------------

2. Consideration of Prior Case Law
    Comment: Multiple state and industry commenters discussed court
decisions involving SSM issues and affirmative defenses predating the
NRDC cases. These commenters generally asserted that the EPA relied too
heavily on the NRDC case in justifying the current action, and that the
EPA failed to address the importance of prior case law and the
relationship between these prior cases and the NRDC case.
    Many of these commenters cited to the Fifth Circuit's Luminant \22\
decision, where commenters asserted the court determined that
affirmative defense provisions do not interfere with a court's
jurisdiction to assess civil penalties or enforce the CAA, contrary to
the D.C. Circuit's decision in NRDC. One commenter, acknowledging the
differing outcomes of the Luminant and NRDC cases, asked the EPA to
discuss this dissonance and claimed that the EPA should have sought en
banc review of the NRDC decision before the full D.C. Circuit, or
alternatively sought review by the Supreme Court. Another commenter
suggested that the EPA should delay finalizing this rule because of the
confusion in the courts resulting from the differing NRDC and Luminant
decisions. Some commenters claimed that the Luminant case is more
directly relevant to the current action than the NRDC case. One
commenter asserted that the Luminant case would be controlling over the
NRDC case in states within the Fifth Circuit's jurisdiction, including
Texas. Some commenters noted that the NRDC case explicitly
distinguished its holding from that of Luminant and avoided confronting
the SIP issues discussed in Luminant. Similarly, some commenters cited
the Eleventh Circuit's Georgia Power \23\ case, which also involved
affirmative defense provisions contained within a SIP. Some commenters
also cited two cases where circuit courts upheld the EPA's ability to
use affirmative defense provisions in Federal Implementation Plans
(FIPs), including the Ninth Circuit's Montana Sulphur \24\ decision and
the Tenth Circuit's Arizona Public

Service \25\ case. Other commenters cited to prior cases decided in the
context of Clean Water Act regulations, including Marathon Oil \26\ and
Essex Chemical,\27\ and claimed that these cases support the creation
of mechanisms like affirmative defenses to account for the
unforeseeable and uncontrollable failure of even the best technology.
---------------------------------------------------------------------------

    \22\ Luminant Generation Co. v. EPA, 714 F.3d 841 (5th Cir.
2013).
    \23\ Sierra Club v. Georgia Power, 443 F.3d 1346, 1357 (11th
Cir. 2006).
    \24\ Montana Sulphur & Chemical Co. v. EPA, 666 F.3d 1174 (9th
Cir. 2012).
    \25\ Arizona Public Service v. EPA, 562 F.3d 1116 (10th Cir.
2009).
    \26\ Marathon Oil Co. v. EPA, 564 F.2d 1253 (9th Cir. 1977).
    \27\ Essex Chemical Corp. v. Ruckelshaus, 486 F.2d 427 (D.C.
Cir. 1973).
---------------------------------------------------------------------------

    Some commenters also addressed the D.C. Circuit's U.S. Sugar
decision. One commenter claimed generally that the case did not
undercut the EPA's basis for providing the title V emergency
affirmative defense. Other commenters, however, claimed that U.S. Sugar
reinforced the EPA's view that affirmative defense provisions that
constrain or interfere with a court's authority under CAA sections 113
and 304 are inimical to the Act.
    Response: The EPA acknowledges that various circuit court cases
preceding the D.C. Circuit's NRDC decision, including the Fifth
Circuit's Luminant decision, upheld the agency's prior interpretation
of affirmative defense provisions in various contexts, including the
authority of the EPA to approve affirmative defense provisions
contained in SIPs and the authority of the EPA to create affirmative
defense provisions in FIPs. In these decisions, the courts deferred to
the EPA's prior interpretation of the CAA with respect to affirmative
defense provisions.\28\ While some courts found the EPA's former
interpretation permissible, those courts did not determine that the
EPA's former interpretation was the only or even the best permissible
interpretation. As previously noted, it is well within the EPA's legal
authority to now revise its interpretation to a different
interpretation of the CAA.\29\ Those prior decisions were based upon an
interpretation of the CAA that the agency no longer holds, and
therefore those prior decisions do not speak to the validity of the
EPA's current policy with respect to affirmative defenses. The EPA
further notes that the affirmative defense provisions at issue in the
other court decisions cited by the commenters, including affirmative
defenses in SIPs and FIPs, are not affected by this action.
---------------------------------------------------------------------------

    \28\ For example, the Fifth Circuit in Luminant held that the
EPA's interpretation of the CAA at that time was a ``permissible
interpretation of section [113], warranting deference.'' 714 F.3d at
853.
    \29\ FCC v. Fox Television Stations, Inc., 556 U.S. 502, 515
(2009); Motor Vehicle Mfrs. Ass'n v. State Farm Mutual Auto. Ins.
Co., 463 U.S. 29, 42 (1983).
---------------------------------------------------------------------------

    In NRDC, however, the D.C. Circuit conclusively determined that the
EPA's former interpretation of the CAA concerning affirmative defenses
was not permissible with respect to section 112 standards promulgated
by the EPA. The NRDC court vacated the affirmative defense provisions
in that case, finding them without legal basis because they
contradicted fundamental requirements of the Act concerning the
authority of courts to decide whether to assess civil penalties in CAA
enforcement suits. Because the NRDC decision interprets CAA sections
113 and 304 and addresses the legal basis for affirmative defense
provisions, the EPA has reevaluated its interpretation of the CAA with
respect to affirmative defense provisions in title V programs as well.
Based on this reevaluation and the reasoning of the NRDC decision, the
EPA has determined that it is appropriate to remove the emergency
affirmative defense provisions in 40 CFR 70.6(g) and 71.6(g), and to
require removal of similar affirmative defense provisions from state
operating permit programs and individual operating permits, because
these provisions are not authorized by the CAA.
    Finally, the EPA notes that the D.C. Circuit's U.S. Sugar decision
further reinforced the principles underlying the NRDC decision. In U.S.
Sugar, the D.C. Circuit, acknowledging that the EPA could not create an
exemption or affirmative defense provision, deferred to the EPA's
decision to rely on case-by-case enforcement discretion as the
mechanism to handle excess emissions during malfunctions.\30\ Arguments
suggesting that prior cases, including Marathon Oil and Essex Chemical,
require the EPA to provide affirmative defenses in such situations are
contrary to the U.S. Sugar decision.
---------------------------------------------------------------------------

    \30\ U.S. Sugar, 830 F.3d at 607-09.
---------------------------------------------------------------------------

3. EPA's Historical Policies Concerning Affirmative Defense Provisions
    Comment: A number of commenters addressed the EPA's historical
policies concerning affirmative defenses,\31\ including the title V
emergency provisions and the policy considerations underlying this type
of mechanism to address emissions in unusual situations. Many
commenters discussed the EPA's initial decision to create the title V
affirmative defense in the 1992 part 70 rule and 1996 part 71 rule. One
commenter claimed that the EPA initially included the title V
provisions to do what was right, even if the EPA did not concede that
it was required. Commenters focused on the initial purpose of the
emergency provisions, asserting that the affirmative defense provisions
were a very limited, appropriate recognition that even properly
designed and maintained technology is not infallible and can fail due
to emergencies beyond the control of a source. Other commenters noted
the EPA's prior approach that acknowledged that enforcement and the
imposition of penalties might not be appropriate in certain situations
beyond the control of the source. Commenters asserted that the NRDC
decision does not undermine the policy reasons that initially informed
the promulgation of affirmative defense provisions, and that these same
policy reasons support the title V emergency affirmative defense
provisions.
---------------------------------------------------------------------------

    \31\ Some commenters also discussed the EPA's historical policy
on exemptions prior to the Sierra Club case.
---------------------------------------------------------------------------

    Commenters also claimed that the title V emergency provisions are
consistent with decades of EPA policy, citing various rulemakings and
guidance documents. Commenters also stated that these types of
affirmative defense provisions were recognized by states long before
the 1990 CAA Amendments and the title V operating permits program, and
that the title V affirmative defense provisions have existed for over
25 years. Commenters also pointed to other EPA actions justifying
affirmative defenses, including FIPs for Montana and New Mexico, EPA's
briefs prepared for litigation in the Luminant case, and EPA's
withdrawal of Texas' SIP Call. Commenters also noted that affirmative
defense provisions are still contained in other regulations promulgated
by the EPA, including NSPS and NESHAP standards.
    Some commenters addressed the EPA's legal authority to change its
policy on affirmative defenses. Commenters asserted that agencies are
only permitted to change their existing interpretations when they offer
a reasoned explanation for the change, citing various Supreme Court
cases including Encino Motorcars, LLC v. Navarro \32\ and FCC v. Fox
Television Stations.\33\ These commenters alleged that the EPA's action
is arbitrary and capricious because the EPA has failed to provide an
adequate justification for the agency's revised policy with respect to
the title V affirmative defenses. However, other commenters
acknowledged that the EPA may change its interpretation so long as the
agency provides a reasoned explanation, and

agreed that the justifications provided by the EPA in the 2016 and 2022
proposed rules are sufficient.
---------------------------------------------------------------------------

    \32\ 136 S. Ct. 2117 (2016).
    \33\ 556 U.S. 502 (2009).
---------------------------------------------------------------------------

    Finally, some commenters discussed the perceived inequity or
unfairness of the EPA's change in policy and removal of affirmative
defense provisions, based in part on the supposition that sources have
come to rely on these provisions. Specific comments addressing how the
removal of the title V affirmative defense provisions could impact
sources are discussed further in section III.D.2. of this document.
    Response: The EPA acknowledges the underlying considerations
supporting the EPA's past policies--especially the agency's recognition
that even well-designed and appropriately operated equipment may
sometimes fail due to circumstances beyond the control of the source
(such as during emergencies) and that, in certain situations,
enforcement for violations of technology-based standards may not be
appropriate. This rule does not change that general recognition. As
discussed in section III.D.2. of this document, the EPA continues to
believe that enforcement may not be warranted under certain specific
circumstances, such as during an emergency, as determined on a case-by-
case basis by enforcement authorities. The EPA, states, citizens, and
the courts retain the discretion and authority to consider such
circumstances in evaluating how to respond to exceedances or
violations. However, an affirmative defense provision that interferes
with the authority of courts to assess penalties is no longer an
appropriate or legally sound mechanism to address these situations.
    The EPA also acknowledges its past policies regarding different
mechanisms to account for excess emissions during periods of SSM and
emergencies. Based on these former policies, the EPA previously
established affirmative defense provisions in various other CAA program
areas, including within previously promulgated FIPs and various NSPS
and NESHAP regulations. However, since that time, decisions from the
D.C. Circuit, including Sierra Club and NRDC, have established
parameters under the CAA regarding legally permissible approaches for
addressing excess emissions during periods of SSM or emergency events.
In light of these decisions--particularly the 2014 NRDC decision--the
EPA has concluded that certain aspects of its prior interpretation of
the CAA were not legally permissible under the CAA. Thus, the EPA has
revised its interpretation of the CAA with respect to affirmative
defense provisions, and this revised interpretation provides the basis
for the current action (and similar actions in other CAA program
areas).
    Following the 2016 proposal, the EPA continued to evaluate SSM
provisions, including affirmative defenses, in SIPs. In October 2020,
the EPA issued a guidance memorandum that, among other things,
expressly superseded a portion of the EPA's interpretation of
affirmative defenses presented in the 2015 SSM SIP Policy.\34\ However,
on September 30, 2021, the EPA issued a guidance memorandum that
withdrew the October 2020 memorandum in its entirety and reinstated the
legal and policy positions expressed in the 2015 SSM SIP Policy in
their entirety.\35\ Thus, the EPA's current interpretation of
affirmative defenses in the context of SIPs is the interpretation set
out in the 2015 SSM SIP Policy.
---------------------------------------------------------------------------

    \34\ Memorandum, Inclusion of Provisions Governing Periods of
Startup, Shutdown, and Malfunctions in State Implementation Plans, 6
(October 9, 2020), available at https://www.epa.gov/system/files/documents/2021-09/2020-ssm-in-sipsguidance-memo.pdf. In 2020, EPA
also took action relating to an SSM-related affirmative defense in a
SIP for Texas, withdrawing a SSM ``SIP call'' in part because the
SIP-based affirmative defense was deemed to not be inconsistent with
the CAA. See 85 FR 7232 (February 7, 2020); see also 85 FR 23700
(April 28, 2020) (SIP call withdrawal relating to North Carolina)
and 85 FR 73218 (November 17, 2020) (SIP call withdrawal relating to
Iowa). Petitions for review of these withdrawal actions were filed
in the United States Court of Appeals for the D.C. Circuit. See
Sierra Club v. EPA, No. 20-1115.
    \35\ September 2021 SSM SIP Memo, supra note 5. This memorandum
also announced an intent to revisit, among other things, the 2020
action withdrawing the SSM affirmative defense-related SIP call for
Texas. Id. at 5. On December 17, 2021, the United States Court of
Appeals for the D.C. Circuit granted the EPA's request for a
voluntary remand of that 2020 Texas SIP call withdrawal action, as
well as the similar SIP call withdrawal actions relating to North
Carolina and Iowa, in light of EPA's stated intent to reconsider
those actions. Sierra Club v. EPA, No. 20-1115.
---------------------------------------------------------------------------

    The EPA's revised interpretation following the NRDC decision was,
and continues to be, well within the EPA's legal authority, and the EPA
has properly exercised its authority to revise its interpretation of
the CAA through the appropriate processes. The authority of an agency
to change its interpretation of a statute is well-established, provided
that it gives a reasoned explanation for the change.\36\ The EPA
disagrees with commenters that suggest that the EPA has not provided an
adequate rationale for this shift in policy, either generally with
respect to affirmative defenses or specifically with respect to the
title V emergency affirmative defense provisions. The EPA has clearly
articulated its revised interpretation of the CAA with respect to
affirmative defenses, here and in other documents, including the 2016
proposed rule (as referenced in the 2022 proposed rule), based on the
EPA's analysis of the NRDC decision.\37\ Commenters have not
substantiated their claim that the EPA's rationale is inadequate.
---------------------------------------------------------------------------

    \36\ See, e.g., Encino Motorcars, 136 S. Ct. at 2125-26; FCC v.
Fox Television Stations, Inc., 556 U.S. 502 (2009); see also Nat'l
Cable & Telecomms. Ass'n v. Brand X internet Servs., 545 U.S. 967,
981-82 (2005) (agency must adequately explain the reasons for a
reversal of policy).
    \37\ The EPA has clearly explained its general shift in policy
with respect to affirmative defense provisions in other documents.
See, e.g., 81 FR 36849; SSM SIP Action Supplemental Proposal, 79 FR
55934; SSM SIP Action, 80 FR 33851.
---------------------------------------------------------------------------

4. Consistency With Other CAA Program Areas
    Comment: A number of commenters acknowledged and addressed the
EPA's desire to ensure consistent agency policy with respect to
affirmative defense provisions across different CAA program areas.
However, some commenters asserted that consistency between the EPA's
title V regulations and other CAA programs is not a rationale for
taking this action. Other commenters disagreed that the title V
provisions should be removed for consistency with actions like the 2015
SSM SIP Action, arguing that the two actions are distinguishable.
Finally, some commenters claimed that removal of the title V
affirmative defense would actually undermine the goal of consistency
across CAA program areas, because title V permits incorporate emission
limits developed under numerous CAA regulatory authorities, and because
various NSPS, NESHAP, and SIP regulations currently still contain
affirmative defense provisions.
    One commenter also suggested that the EPA could resolve any
inconsistency between the title V affirmative defense provisions and
underlying standards that do not allow an affirmative defense by
clarifying through an interpretive rule or rule revision that
nationwide standards outweigh affirmative defense provisions under
title V.
    Response: The EPA is not removing the title V emergency affirmative
defense provisions solely for the sake of consistency. Rather, as
discussed in the proposal and in section III.A. of this document, these
provisions present legal issues substantially similar to those that
called for the removal of affirmative defense provisions from other
regulations. In addition to the legal considerations supporting the
current action, and as previously explained in the preamble to the 2016
proposed rule (as referenced in the 2022 proposal), the EPA believes
that it is important to apply, as much as

reasonably possible, the EPA's policy concerning affirmative defense
provisions consistently across CAA program areas. As previously
explained, the EPA has removed affirmative defense provisions from
numerous other CAA standards since the 2014 NRDC decision.\38\ Based on
the relationship between title V and these underlying standards, it is
particularly important to remove the affirmative defense provisions
from the title V program regulations. Title V permits include a wide
range of substantive CAA requirements that apply to a source, including
SIP provisions and standards developed under CAA sections 111, 112, and
129. Because the title V affirmative defense provisions applied
independent of these underlying standards, the title V emergency
affirmative defense might be asserted in civil actions or other
proceedings involving noncompliance with title V permit terms
reflecting standards from which the EPA has recently eliminated
affirmative defenses. In this way, the continued presence of the title
V affirmative defense provisions could effectively undermine the EPA's
efforts to remove affirmative defenses from the underlying standards,
as well as the efforts of states to revise SIPs to comply with the 2015
SSM SIP Action. The EPA acknowledges that not all affirmative defense
provisions in the EPA's regulations have been removed as of the date of
this rule. However, the fact that this is an ongoing process does not
provide a basis for retaining or delaying removal of the title V
affirmative defense provisions.
---------------------------------------------------------------------------

    \38\ 87 FR 19042, 19044, n. 3 (citing recent EPA rulemakings
removing affirmative defense provisions).
---------------------------------------------------------------------------

    Moreover, the EPA does not believe that it would be appropriate to
simply clarify in some manner--whether by revising the emergency
affirmative defense rules or issuing guidance--that the title V
affirmative defense would not apply where the underlying standards do
not allow or provide for an affirmative defense. Although this approach
could potentially reduce inconsistency between title V provisions and
the underlying standards from which affirmative defenses have been
removed, it would nonetheless fail to address the more fundamental
problem that the title V affirmative defense provisions are, in and of
themselves, inconsistent with the enforcement structure of the CAA and
thus legally impermissible.
5. Relationship to Other CAA Standards
    Comment: Commenters raised a number of concerns involving the
relationship between the title V emergency affirmative defense and
other CAA standards, including section 112 NESHAP, section 111 NSPS,
and SIPs. Comments specifically relating to SIPs are discussed in the
following subsection.
    Commenters claimed generally that the EPA has failed to consider
how the CAA requirements related to enforcement must be harmonized with
the CAA requirements relating to standard setting and permitting. One
commenter claimed that the title V affirmative defense provisions avoid
the need to address emergencies in each individual underlying standard,
which the commenter characterized as an impractical approach. Another
commenter asserted that the title V affirmative defense provisions have
effectively become part of the underlying applicable standards, and
other commenters suggested that the title V affirmative defense
provisions are necessary to ensure that underlying technology-based
standards are achievable and adequately demonstrated, taking into
account costs. These commenters asserted that removing the affirmative
defense would have the effect of making the underlying standards in a
permit more stringent than those authorized by the governing standards,
in that sources would be subject to a level of control technology that
is technologically and economically infeasible. Other commenters
suggested that if affirmative defenses are removed, either title V
permits or underlying standards would need to provide some other way to
account for malfunctions, such as through alternative emission
limitations, work practice standards, or malfunction abatement plans.
    Some commenters also claimed that the overlap between the title V
emergency provisions and various malfunction provisions in NSPS and
NESHAP regulations could cause confusion. However, other commenters
recognized that the removal of the title V affirmative defense
provisions should not have any impact on independent malfunction or
emergency provisions contained in underlying technology-based
standards.
    Lastly, several environmental commenters asserted that EPA must go
further and quickly remove ``SSM loopholes'' from other CAA programs,
including section 111 NSPS, section 112 NESHAP, and SIPs.
    Response: Many of the comments relating to malfunction emissions
and the development of technology-based standards are either not
directly related to the current rule to remove the title V emergency
affirmative defense provisions or reflect a misunderstanding about the
relationship between the title V affirmative defense provisions and
underlying standards included within operating permits. As an initial
matter, title V of the CAA does not generally impose new substantive
requirements on a source. Rather, title V permits provide a vehicle to
clarify in a single document the various CAA requirements applicable to
a source. Although title V permits must contain conditions (such as
monitoring, recordkeeping, and reporting provisions) necessary to
assure compliance with all CAA requirements already applicable to a
source, title V of the CAA does not provide the basis for making
substantive changes to underlying applicable standards.\39\ Therefore,
title V permits are not an appropriate mechanism for addressing
commenters' concerns related to the development of, for example,
alternative emission limits, work practice standards, or malfunction
abatement plans. These considerations may be more relevant in the
context of developing specific SIP provisions or section 111, 112 or
129 standards.\40\
---------------------------------------------------------------------------

    \39\ 40 CFR 70.1(b) (requiring all title V sources to have a
permit to operate that ``assures compliance by the source with all
applicable requirements'' and stating that ``title V does not impose
substantive new requirements,'' although it does require imposition
of fees and certain compliance measures).
    \40\ The D.C. Circuit's U.S. Sugar decision addressed arguments,
raised in the context of challenges to NESHAPs issued under CAA
section 112 that did not provide for an affirmative defense for
unavoidable malfunctions, that such malfunctions must be accounted
for either by an affirmative defense or by appropriate adjustments
in the standard-setting itself. The D.C. Circuit upheld the EPA's
decision to neither include an affirmative defense nor adjust the
underlying standard, as requested by Petitioners, to account for
malfunction periods. Instead, the court upheld the EPA's decision to
use enforcement discretion to address exceedances that occur during
malfunction periods.
---------------------------------------------------------------------------

    Moreover, the underlying standards, not the title V affirmative
defense provisions, establish the appropriate level of emission
controls, accounting for technological, economic, and other
considerations, as appropriate. The title V emergency affirmative
defense provisions are not, as some commenters suggested, part of the
underlying applicable requirements themselves. The title V affirmative
defense provisions operated independently from the specific standards
and/or emission limits, as well as any emergency, malfunction, or upset
provisions contained within underlying applicable

requirements. Although the title V provisions provided for an
affirmative defense in emergencies, removal of the affirmative defenses
would not make underlying technology-based standards more stringent or
otherwise have any effect on standards applicable to a source. The
title V provisions merely provided an affirmative defense that a
source, after having allegedly violated a technology-based emission
limitation contained in its title V permit, could assert in an
enforcement proceeding brought for alleged violations of the title V
permit term reflecting the requirements of the underlying standard.
Because the title V affirmative defense did not provide an exemption to
any standard or define when a violation of a standard has occurred, a
source's compliance status with the underlying standard itself--as well
as the source's compliance status with the title V permit term--would
not be affected by the presence or absence of an affirmative defense.
    Finally, comments discussing the purported need to provide for or
address excess emissions associated with malfunctions are immaterial
because this action addresses the title V affirmative defense
provisions for emergencies, which--although there may be some
similarities--are significantly different, and narrower, than
malfunction events. For further discussion, see section III.D.3. of
this document.
6. Relationship to the 2015 SSM SIP Action
    Comment: Multiple commenters addressed the relationship between
this action and the 2015 SSM SIP Action. Some commenters asserted that
the EPA's current action is based on the 2015 SSM SIP Action, or
claimed that the two actions are related for various reasons. Other
commenters claimed that the 2015 SSM SIP Action is not at issue in this
rulemaking, disagreed with the EPA's statements that certain aspects of
the 2015 SSM SIP Action are especially relevant, and attempted to
distinguish the types of provisions at issue in the 2015 SSM SIP Action
from those at issue here.
    Some commenters also specifically discussed the need for states to
develop SIP provisions that account for SSM situations (including work
practice standards) and claimed that states should not be prohibited
from including approved state SSM plans in title V permits. One
commenter suggested that removing the title V affirmative defense
provisions before SIP issues are resolved could prevent states from
incorporating all applicable requirements, including SIP requirements,
into title V permits, and another commenter asserted that this title V
rule should be withdrawn while states modify their rules to address the
2015 SSM SIP Action. On the other hand, other commenters suggested that
by promptly finalizing this title V rule, the EPA can better facilitate
the coordination of SSM SIP revisions with title V program revisions
and individual operating permit revisions.
    Response: This current title V rule is related to the 2015 SSM SIP
Action to the extent that each rule is based at least in part on the
EPA's view that, in light of the NRDC decision, affirmative defense
provisions are contrary to the enforcement structure of the CAA.\41\
However, this title V action is not ``based on'' the 2015 SSM SIP
Action, and the two actions are functionally independent rulemakings,
each operating within distinct areas of the CAA's regulatory structure.
Therefore, and for the reasons discussed in the preceding subsection
discussing the relationship between title V and other CAA standards,
this current action involving the title V affirmative defense
provisions will not have any effect on states' ability to develop
appropriate SIP provisions in response to the 2015 SSM SIP Action, and
it will not affect states' ability to ensure that title V permits
appropriately reflect all requirements applicable to a source,
including revised SIP provisions. In fact, as some commenters
indicated, it may be convenient for states to coordinate implementation
of any title V permit changes related to the 2015 SSM SIP Action with
permit changes related to this rulemaking. Issues regarding
implementation of this rule are discussed further in section IV. of
this document.
---------------------------------------------------------------------------

    \41\ This legal rationale is not affected by any differences
between affirmative defense provisions implicated by the 2015 SSM
SIP Action and those implicated by this action.
---------------------------------------------------------------------------

7. Title V of the CAA
    Comment: Some commenters noted that while title V of the CAA does
not establish or mandate affirmative defense provisions, neither does
title V of the CAA prohibit the EPA from establishing affirmative
defenses.
    Response: The EPA acknowledges that title V of the CAA is silent
with respect to affirmative defense provisions; it neither provides for
such provisions nor explicitly prohibits them. However, the EPA
interprets other provisions of the CAA that apply to enforcement of the
title V operating permits program--including sections 113 and 304--to
effectively prohibit the creation of affirmative defense provisions, as
discussed in section III.A.1. of this document.
8. Constitutional Issues
    Comment: Some commenters raised constitutional issues with the
removal of the title V emergency affirmative defense provisions.
Commenters argued that the imposition of penalties for any conduct that
is unavoidable violates basic constitutional protections guaranteed by
the Eighth Amendment and due process requirements. Commenters further
asserted that explicit affirmative defense provisions are necessary to
satisfy minimum constitutional standards, and that alternative
approaches, such as the exercise of enforcement discretion, are not
sufficient.
    Response: The EPA disagrees with commenters with respect to these
constitutional arguments. The comments suggest that without the title V
affirmative defense, any penalty assessed for violation of a title V
permit term during an emergency would be per se ``excessive'' or
``arbitrary'' and that the existing CAA enforcement provisions would be
facially unconstitutional. The EPA disagrees. It should be reiterated,
first, that the title V emergency affirmative defense has never been a
required permit term and it has not universally been adopted by all
permitting authorities for all permits. Even where the defense may be
available, it is, by its own terms, very limited and narrowly
circumscribed. Commenters have provided no information indicating that
the defense has been asserted with any frequency or, indeed, at all. It
is difficult to see how the removal from the EPA's regulations of a
narrowly circumscribed, discretionary defense that apparently is
infrequently asserted could render the CAA unconstitutional.
    Moreover, the CAA does not mandate that EPA automatically initiate
an enforcement action, let alone automatically assess a penalty, for a
violation of a CAA requirement. EPA has absolute discretion on whether
to initiate an enforcement action in any circumstance, including during
an emergency.\42\ If EPA chooses to initiate an enforcement action in a
circumstance involving a violation during an emergency, and chooses to
seek a penalty for that violation, the CAA establishes a maximum civil
penalty in

section 113(b) \43\ but then expressly provides in section 113(e) that
the EPA or the courts ``shall take into consideration various
criteria--including specifically, ``good faith efforts to comply,''
and, more generally, ``other factors as justice may require.'' Thus,
the CAA on its face does not mandate the imposition of any penalty
automatically, much less one that is per se excessive. The commenters
fail to provide any specific support for their claim that the statutory
penalty provisions of the CAA are facially unconstitutional, instead
making only generalized claims.
---------------------------------------------------------------------------

    \42\ Heckler v. Chaney, 470 U.S. 821 (1985) (holding that
decisions of agency not to undertake enforcement action are presumed
unreviewable).
    \43\ The maximum statutory civil monetary penalty amounts are
adjusted annually for inflation in 40 CFR part 19.
---------------------------------------------------------------------------

    In addition, State Farm Mutual Auto Insurance Co. v. Campbell,\44\
a case cited by some commenters, provides no support for any claim that
removal of the title V affirmative defense would somehow be
unconstitutional. State Farm involved a claim that a jury award of $145
million in punitive damages was excessive and, accordingly, contrary to
the Due Process Clause of the Fourteenth Amendment to the United States
Constitution. Reaffirming that the Fourteenth Amendment ``prohibits the
imposition of grossly excessive or arbitrary punishments,'' the Supreme
Court held that, under the particular circumstances of the case, the
punitive damages award was excessive and ``an irrational and arbitrary
deprivation of property.'' \45\ Here, no penalties have been assessed
at all, and State Farm provides no support for the conclusion that--
absent the title V emergency affirmative defenses--the CAA's
authorization, in accordance with various identified criteria, of
possible penalties is necessarily unconstitutional.\46\
---------------------------------------------------------------------------

    \44\ 538 U.S. 408 (2003).
    \45\ Id. at 429.
    \46\ Additionally, State Farm involved a claim under the
Fourteenth Amendment, which imposes limitations on the states, not
the federal government. This discussion assumes, for the sake of
argument, that the principles expressed in State Farm would also
apply to claims under the Due Process Clause of the Fifth Amendment.
---------------------------------------------------------------------------

    The EPA also disagrees with the claims that--absent the title V
affirmative defenses--the penalty provisions of the CAA would be
facially contrary to the Eighth Amendment. Again, if a party believes
that the penalties assessed in a particular enforcement action violate
the Eighth Amendment, it can raise that claim at the appropriate time.
As with the commenters' due process arguments, Congress has addressed
the potential for unfair--or unconstitutional--penalties by setting out
various criteria to be considered in determining civil penalties. The
penalty criteria in section 113(e) provide an opportunity to raise
concerns about imposition of penalties in the event of an emergency
similar to that afforded by the title V affirmative defenses, albeit
directed at the courts' discretion. The commenters do not explain why
they believe these explicit statutory factors do not provide sufficient
protection against the imposition of an allegedly unconstitutionally
excessive penalty.

D. Potential Impacts

    This section discusses various issues involving the effects of
removing the title V emergency affirmative defense provisions, focusing
primarily on the impact on sources. Overall, the EPA does not believe
that removing the emergency affirmative defense provisions will
substantially affect the legal rights of title V sources or the
decisions sources make when confronted with emergency situations. It is
also important to reiterate that the EPA is basing the current action
on its interpretation of the CAA in light of relevant caselaw
indicating that these affirmative defense provisions must be removed
because they are inconsistent with the enforcement structure of the
CAA.
1. Scope and Use of Title V Affirmative Defense Provisions
    Comment: Multiple state and industry commenters acknowledged the
limited scope of the title V affirmative defense provisions, which
apply only to emergency situations. Commenters also addressed the
relationship between emergencies and malfunctions. While some
commenters provided examples of situations that would constitute an
emergency but not a malfunction, other commenters asserted that the
terms ``emergency'' and ``malfunction'' are closely related in that
they both relate to unexpected and unforeseen events.
    A number of commenters further acknowledged the limited historical
and potential use of the title V emergency affirmative defense
provisions. However, commenters suggested that the rule could have
greater impacts than might be apparent.
    Environmental commenters, on the other hand, characterized large
SSM exceedances as routine and claimed that large polluters have used
affirmative defense provisions in many citizen enforcement actions.
Additionally, these commenters asserted that excess emissions are often
the result of operator errors, poor plant design, and a lack of
preventive maintenance. Thus, commenters claimed that sources using SSM
affirmative defense provisions have lacked an incentive to make
investments in accident prevention. Finally, these commenters claimed
that emissions during SSM and emergency events can be controlled.
    Response: The EPA agrees with commenters that emphasized the
limited scope of the title V emergency affirmative defense provisions.
Unlike more general affirmative defense provisions addressing excess
emissions during equipment malfunctions (which some commenters appear
to address), the title V provisions being removed were specific to
situations that qualify as an ``emergency,'' defined as ``any situation
arising from sudden and reasonably unforeseeable events beyond the
control of the source, including acts of God, which situation requires
immediate corrective action to restore normal operation, and that
causes the source to exceed a technology-based emission limitation
under the permit, due to unavoidable increases in emissions
attributable to the emergency.'' 40 CFR 70.6(g)(1). Thus, while the
title V emergency affirmative defenses, like affirmative defenses for
malfunctions, relate to events that are beyond the control of a source,
the title V defenses would only have been available in a more extreme,
limited set of circumstances. While it is possible for some overlap in
malfunction and emergency situations to exist (e.g., certain emergency
events could potentially cause equipment malfunctions), the EPA
believes that the majority of exceedances during malfunction events
would not be attributable to ``emergencies'' as defined in the title V
affirmative defense provisions. In addition, the title V affirmative
defense provisions being removed contain various procedural
requirements that must be met to assert the defense. See 40 CFR
70.6(g)(3). Moreover, as some commenters acknowledged and based on the
best information available to the EPA, the title V emergency
affirmative defense provisions have rarely, if ever, been asserted in
enforcement proceedings. Comments contending that sources frequently or
routinely have asserted affirmative defenses appear to relate to SSM
affirmative defenses, rather than the narrower title V affirmative
defense for emergencies. It is unlikely that the criteria for the title
V emergency affirmative defense would have been met in such
circumstances, as the title V provisions could not be asserted for
(among other things) noncompliance caused by improperly designed
equipment, lack of preventative

maintenance, careless or improper operation, or operator error.
    For these reasons, the EPA does not believe that the removal of the
narrowly drawn and apparently infrequently used title V emergency
affirmative defense provisions will have a significant impact on
sources. Further, as discussed in the following subsection, the EPA,
state authorities, and other entities likely would consider the
relevant circumstances--especially the relatively unusual, extreme, and
unavoidable circumstances that would have qualified under the narrow
definition of ``emergency''--in deciding whether to pursue enforcement
action or seek penalties, and sources remain free to argue to the
court, in the event of an enforcement action, that penalties should not
be assessed for these same reasons.
2. Alternatives to an Affirmative Defense: Discretion To Initiate
Enforcement and the Discretion of Decision Makers To Determine
Appropriate Remedies
    Comment: Many commenters expressed concerns that removing the title
V emergency affirmative defense provisions would result in less
certainty or greater risk of liability to sources confronted with
emergency situations. One commenter asserted that even if the EPA is
not legally required to provide an affirmative defense in title V
permits, the EPA should, to the maximum extent consistent with law,
continue to provide and allow states to provide sources relief from the
threat of enforcement for exceedances caused by emergencies. Another
commenter claimed more generally that the EPA must find other ways to
assure sources that they will not be subject to penalties if they
operate to provide vital services in an emergency. Commenters generally
requested additional guidance from the EPA to provide more certainty to
sources in the absence of an explicitly codified affirmative defense.
    Most commenters acknowledged the fact that even in the absence of
an affirmative defense, the EPA, state, and citizens all retain the
discretion to determine whether to bring an enforcement action, based
on the unique circumstances of each case. Thus, most commenters
acknowledged that not all exceedances of emission limits will
automatically result in enforcement actions. One commenter asserted
that the EPA routinely uses enforcement discretion to decide which
alleged violations to pursue, and that such decisions are often made on
the same principles codified in an affirmative defense. Other
commenters asserted that the EPA does not intend for true emergencies
to result in increased enforcement, and that the EPA's suggested
enforcement discretion approach avoids forcing every violation to
judicial resolution. Finally, one commenter asserted that the exercise
of enforcement discretion by state permitting authorities is
appropriate and consistent with CAA sections 113 and 304 and separation
of power principles.
    However, a number of commenters challenged the sufficiency of
relying on enforcement discretion alone to handle excess emissions
caused by emergencies. Commenters noted that explicitly codified
affirmative defense provisions have the benefit of providing certainty
to permittees, promoting consistency to agency actions, and promoting
the creation and retention of records necessary to justify agency
actions. Commenters claimed that relying on enforcement discretion
alone would result in more uncertainty and jeopardy and less harmony
among different CAA programs, because enforcement discretion policies
may be unwritten and unavailable to the public. Other commenters noted,
citing the U.S. Sugar decision, that federal and state policies
regarding enforcement discretion do nothing to prevent citizens from
pursuing enforcement. Some commenters also asserted that an enforcement
discretion approach still leaves sources in the difficult position of
choosing between proper emergency response and compliance with emission
limits. Other commenters claimed that relying on enforcement discretion
puts all power in the hands of the EPA, without any checks and
balances, and asserted that this contradicts principles of cooperative
federalism and exceeds the authority intended in the passage of the
CAA.
    Some commenters discussed how prior court decisions have treated
enforcement discretion. One commenter claimed that the D.C. Circuit in
U.S. Sugar acknowledged, but did not evaluate, the EPA's reliance on
enforcement discretion, and the commenter alleged that the court
appeared to have doubts that enforcement discretion alone is
sufficient. Another commenter claimed that the U.S. Sugar decision did
not validate the enforcement discretion approach beyond the context of
section 112 standards. Other commenters cited to the 1973 D.C. Circuit
opinion in Portland Cement Assn. v. Ruckelshaus \47\ in support of
their position that reliance on enforcement discretion is not a
sufficient response to addressing excess emissions from malfunctions,
and another commenter claimed that the 9th Circuit rejected the EPA's
use of enforcement discretion in the 1977 Marathon Oil \48\ Clean Water
Act case.
---------------------------------------------------------------------------

    \47\ 486 F.2d 375, 399 n.91 (D.C. Cir. 1973).
    \48\ Marathon Oil Co v. EPA, 564 F.2d 1253, 1272-73 (9th Cir.
1977).
---------------------------------------------------------------------------

    Some commenters requested that the EPA provide additional guidance
to clarify the circumstances under which permitting authorities
(including the EPA) should exercise their discretion not to bring
enforcement actions. Many commenters encouraged the use of the criteria
contained in 40 CFR 70.6(g) in guiding permitting authorities' exercise
of enforcement discretion. Some commenters asserted that states should
be able to rely on those criteria when exercising their enforcement
discretion. Other commenters urged the EPA: to make clear that the EPA
would not expect to bring an enforcement action under circumstances
meeting those criteria; to make clear that the EPA would continue to
use its enforcement discretion in the case of emergency situations; and
to create a strong policy statement that the EPA does not support civil
penalties in situations meeting those criteria. Commenters, with one
quoting a passage from the EPA's brief in the U.S. Sugar case, urged
the EPA to more fully articulate certain standards for determining
whether the EPA would pursue enforcement in a given situation,
including consideration of the good faith efforts of a source to
minimize emissions, which types of preventative and corrective actions
would be considered, and the nature and extent of the root cause
analysis that should be employed by sources to ascertain and rectify
excess emissions. Another commenter claimed that it is appropriate for
permitting authorities to take into account circumstances involving how
a source mitigated damage to people and the environment in responding
to an emergency.
    Relatedly, one commenter suggested that instead of removing the
affirmative defense provisions, the EPA should amend them to provide
that the affirmative defense may be allowed, if specified conditions
are met, at the discretion of the enforcement entity.
    Commenters also acknowledged that even when an enforcement action
is commenced, the ultimate decision makers also have the discretion to
determine whether and to what extent penalties are appropriate in a
given situation. Environmental commenters asserted that both the EPA
and the NRDC court recognized that even

without an affirmative defense, sources are still free to argue to a
court that they should be subject to lesser (or no) civil penalties for
any number of reasons, including practical considerations or
emergencies. Another commenter noted that the D.C. Circuit in U.S.
Sugar confirmed that sources may still argue to a court that penalties
should not be assessed in a given situation, and that sources may
support these arguments with relevant facts, such as the source's
compliance history and good faith efforts to comply with emission
limits.
    However, while some commenters acknowledged that the absence of an
affirmative defense would not automatically result in the imposition of
particular remedies, other commenters asserted that without an
affirmative defense, sources would lack a legal defense in enforcement
actions and would be liable for unforeseeable events outside of their
control. One commenter claimed that this would be unjust, and that
imposing an unjust system would foster disrespect for the law.
    Finally, some commenters requested further guidance on how sources
could make similar defenses in enforcement proceedings. Commenters
requested that the EPA retain or narrow the definition of ``emergency''
in its regulations, as this definition could help guide a court's
review of circumstances that are unlikely to warrant punishment, and
could provide more certainty to sources.
    Response: As discussed in detail in the 2016 proposal,\49\ the EPA
reiterates that the legal rights and obligations of individual sources
potentially subject to enforcement proceedings will not be
significantly affected by the removal of emergency affirmative defense
provisions from their title V permits. The absence of an affirmative
defense provision in a source's title V permit does not mean that all
exceedances of emission limitations in a title V permit, including
those resulting from an emergency, will automatically be subject to
enforcement or automatically be subject to imposition of penalties or
other remedies.
---------------------------------------------------------------------------

    \49\ See 81 FR 38653.
---------------------------------------------------------------------------

    First, any entity that may bring an action to enforce title V
permit provisions has enforcement discretion that they may exercise as
they deem appropriate in any given circumstance. For example, if the
excess emissions caused by an emergency occurred despite proper
operation of the facility, and despite the permittee taking all
reasonable steps to minimize such emissions, EPA or other relevant
entities may well decide that no enforcement action is warranted in a
specific case. In the event that an entity decides to bring an
enforcement action, it may, nonetheless, take into account the
emergency circumstances in deciding what remedies to seek.
    The EPA appreciates that relying on enforcement discretion might
afford less certainty to sources than an affirmative defense provision.
However, as the EPA has explained, the latter approach is not legally
consistent with the enforcement structure of the CAA, which among other
things imposes a duty on the source to continually comply with emission
limits and standards. Moreover, the EPA believes the exercise of
enforcement discretion in lieu of a codified affirmative defense
provision is both appropriate and sufficient to carry out the mandates
established by Congress in the CAA in a fair and equitable fashion, a
position that the D.C. Circuit upheld in its U.S. Sugar decision.\50\
The EPA believes that it is unlikely that entities would initiate an
enforcement action for emissions exceedances resulting solely from a
true emergency situation that would have qualified under the narrow
definition and particular requirements of the title V emergency
affirmative defense provisions. The EPA also generally agrees with
commenters that the conditions contained in the title V emergency
provisions, including but not limited to the nature of the emergency
event and the source's efforts to take all reasonable steps to minimize
emissions during an emergency, would likely be important considerations
to take into account when deciding whether to pursue enforcement, among
all other relevant factors. Enforcement discretion decisions
necessarily involve case-specific considerations, which should not be
confined to the specific conditions contained in the title V emergency
affirmative defense provisions.\51\ Thus, the EPA will not, in the
course of this rulemaking, provide explicit criteria that the EPA,
states, or other entities should apply in determining whether to
commence an enforcement action. Nothing in this action precludes the
EPA from issuing such guidance in other appropriate proceedings or
formats if the agency should subsequently determine that to be
appropriate.
---------------------------------------------------------------------------

    \50\ In its U.S. Sugar decision, the D.C. Circuit upheld the
EPA's reliance on case-by-case enforcement discretion as a
permissible and reasonable substitute for affirmative defense
provisions in accounting for malfunctions within section 112
standards. U.S. Sugar, 830 F.3d at 607-09. The EPA believes that the
D.C. Circuit's statements in NRDC and U.S. Sugar are more reflective
of the court's current views concerning affirmative defenses and
enforcement discretion than the much earlier decisions cited by
commenters, including Portland Cement Assn. v. Ruckelshaus.
Arguments suggesting that prior cases, including Marathon Oil and
Essex Chemical, require the EPA to provide affirmative defenses in
such situations are contrary to the D.C. Circuit's holdings.
    \51\ These considerations could potentially be much broader than
the title V emergency affirmative defense provisions, and encompass
situations where a source would never have been eligible for the
emergency affirmative defense.
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    Second, even if an enforcement action is commenced for exceedances
caused by an emergency, the absence of an explicitly defined
affirmative defense provision does not affect a source's ability to
demonstrate to the court (or to the EPA in an administrative
enforcement action) that penalties or other kinds of relief are not
warranted. Under section 113(e), courts (and the EPA in an
administrative enforcement action) must consider various factors when
assessing monetary penalties, including the source's compliance
history, good faith efforts to comply for the duration of the
violation, and ``such other factors as justice may require.'' Thus,
with or without an explicit affirmative defense, a source retains the
ability to defend itself in an enforcement action and to oppose the
imposition of particular remedies or to seek the reduction or
elimination of monetary penalties, based on the specific facts and
circumstances of the emergency event. The D.C. Circuit has noted that
such justifications would be a ``good argument . . . to make to the
courts.'' \52\ Thus, overall, elimination of the title V emergency
affirmative defense provisions will not deprive sources of these
defenses in potential enforcement actions. Sources retain all of the
arguments they previously could have made. Congress vested the courts
with the authority to judge how best to weigh the evidence in an
enforcement action and to determine appropriate remedies. The EPA may
not, through the title V affirmative defenses, restrict a court's
ability to do so, and the EPA does not believe that it would be
appropriate, in this action, to provide guidance to the courts with
respect to what factors a court should or must consider.
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    \52\ NRDC, 749 F.3d at 1064.
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    For similar reasons, the EPA does not believe it would be
appropriate or necessary to retain the definition of ``emergency'' or
any of the other provisions formerly contained in 40 CFR 70.6(g) and
71.6(g) that were associated with the title V affirmative defense.
These additional provisions, which were created solely for the purpose
of supporting the title V affirmative defense and ensuring that it was
narrowly tailored, no longer serve

a purpose in the EPA's part 70 and part 71 regulations. For example,
the EPA does not believe that retaining a standalone definition of
``emergency'' without any context or application would be helpful to
relevant entities determining whether to initiate enforcement or to the
courts or an agency determining the appropriate remedies.
    As explained in section III.A., affirmative defense provisions by
their nature limit or eliminate the authority of federal courts to
determine liability or to impose remedies through considerations that
differ from the explicit grants of authority in section 113(b) and
section 113(e). Therefore, these provisions are not appropriate under
the CAA, no matter what type of event they apply to, what criteria they
contain, or what forms of remedy they purport to limit or eliminate.
Thus, it would not be appropriate to amend the title V affirmative
defense provisions to provide that the affirmative defense may be
allowed if specified conditions are met, at the discretion of the
enforcement entity.
3. Impacts on the Decision Making and Planning of Sources Confronted
With Emergency Situations
    Comment: Industry commenters raised concerns involving how the
removal of the title V affirmative defense provisions will affect how
sources plan for and react to emergency situations. Many of these
comments asserted that without an affirmative defense provision in
their title V permits, sources confronted with an emergency situation
would be forced to decide whether to (1) comply with operating permit
requirements or (2) deal with the emergency situation in a manner
protective of human safety or other public interests, at the risk of
being held liable for violating permit terms. Specifically, some
commenters asserted that facilities faced with the threat of liability
may be less willing to shut down systems in an emergency, creating the
risk of more catastrophic accidents. Other commenters suggested that
sources might shut down earlier than would normally be the case, which
could result in resource shortages that could impede emergency response
efforts or area recovery. Commenters asserted that the affirmative
defense provisions serve the important purpose of allowing sources the
flexibility to continue or resume operations to provide vital services
in times of emergency.
    One industry commenter, citing discussion in the EPA's 2014 SSM SIP
Action Supplemental Proposal, asserted that removing the affirmative
defense provisions could result in an additional resource burden for
sources, who could be forced to invest in facility improvements in
order to protect the source from emergency situations.
    Other commenters asserted similar arguments specifically concerning
electric grid reliability, asserting that sources would have to weigh
compliance obligations against the need to continue generating
electricity to avert grid reliability problems. Some commenters
generally claimed, without describing specific instances, that the
title V emergency affirmative defense provisions, in addition to other
available mechanisms for relief from penalties, have helped ensure
reliable electric grid operation in emergency situations. Several
commenters provided specific examples of these situations.
    Commenters presented differing views of whether the definition of
``emergency'' in the title V affirmative defense provisions would
encompass reliability or electric system emergencies. One commenter
asserted that the definition of ``emergency'' should cover an extreme
situation involving critical reliability concerns because the EPA has
recognized that CAA rules need to account for the unique interconnected
and interdependent operations of power plants. However, another
commenter acknowledged that the definition may not be broad enough to
cover this situation, but suggested that the EPA recognize that
enforcement may be unwarranted not only for unit-specific emergencies,
but also for situations where facilities are called upon to support
reliability in the context of a larger electric system emergency.
    Some commenters claimed that certain electric system operators
cannot force a source to continue generating electricity in order to
ensure system reliability if doing so would cause the source to violate
an environmental requirement, such as a permit condition. Thus, these
commenters expressed concern that without the title V affirmative
defense--characterized by the commenters as an ``exemption''--electric
system operators would not be able to force a source to generate
electricity in order to ensure system reliability. Other commenters
discussed emergency generation orders issued by the Department of
Energy (DOE) under section 202(c) of the Federal Power Act (FPA), 16
U.S.C. 824a(c), by which the DOE may require power plant owners to
operate and generate electricity in certain emergency situations. While
some commenters expressed concern that a source could face the risk of
significant penalties for emissions exceedances resulting from
complying with such an order, other commenters discussed an amendment
to the FPA that excuses sources from compliance with environmental
regulations when necessary to comply with DOE emergency orders. One
commenter concluded that this FPA provision should be viewed as
complementary to, rather than a substitute for, the title V emergency
defense, and another asserted that this legislation indicates
congressional support for an emergency defense when electric system
reliability is at issue.
    Commenters urged the EPA to consult with other agencies with
expertise in reliability. Commenters also suggested that the EPA direct
federal and state enforcement offices to engage in close consultation
with relevant grid operators or reliability authorities prior to
initiating enforcement actions where exceedances were caused by a
demonstrated reliability need. Commenters also proposed that system
operators should be able to submit a reliability analysis in the record
of any enforcement proceeding and suggested that courts should not
independently assess previously established reliability-related
determinations.
    Response: The EPA does not believe that the removal of the title V
emergency affirmative defense provisions will significantly affect the
decision making of sources confronted with emergency situations.
Sources confronted with an emergency situation will always have to
assess the risk of liability involved with courses of action that would
result in exceedances of emission limits contained in title V permits
as well as the underlying standards. The EPA does not believe that
removing the title V affirmative defense provisions will affect this
risk assessment. First, the title V emergency provisions did not
provide guaranteed protection from liability. They simply created an
affirmative defense that a source, having allegedly violated a
technology-based emissions limit, could assert in narrowly defined
circumstances after an enforcement action was initiated. Moreover,
permittees seeking to assert the defense bore the burden of
establishing that a number of required conditions were met.
    Second, the incentives that exist for sources to behave in a
prudent manner during emergencies remain largely unchanged, even
without an explicit affirmative defense. As discussed in section
III.D.2. of this document, sources can still argue all available

defenses to an alleged violation and/or assert that penalties should
not be imposed, based on the particular circumstances. The ability to
assert relevant considerations in this manner is not limited to the
particular conditions associated with the title V emergency affirmative
defense provisions. The EPA agrees that the need to avert catastrophic
accidents, or to avert an electric reliability crisis, or any number of
other public interest-related considerations, could be especially
relevant to the decision whether to pursue enforcement or impose
penalties. The EPA cannot, however, restrict or define--through the
operation of an affirmative defense or otherwise--the evidence or
considerations that a court may take into account when determining
whether penalties should be assessed in a given situation.
    Additionally, the EPA does not believe that removing the title V
emergency affirmative defense provisions will have a significant effect
on how sources plan for emergencies or invest in facility improvements
in order to prepare for emergencies. The EPA notes that the comments
received on this point, and the EPA's statements in the 2014 SSM
Supplemental Proposal cited by commenters, are more relevant to
preparing for excess emissions from equipment malfunctions than to
preparing for emergencies. Moreover, as discussed previously, removing
the affirmative defense provisions should not change the incentives
that sources have to prepare for emergencies. Prudent behavior with
respect to planning for emergency situations and minimizing emissions
during an emergency to the maximum extent possible would be just as
advantageous to a source seeking to reduce the possibility that
enforcement will be initiated (or seeking to establish that penalties
are not appropriate) as it would be to a source attempting to meet the
criteria of a codified affirmative defense provision. The EPA believes
that such prudent behavior is a matter of good business practice that
most, if not all, sources would normally pursue irrespective of an
affirmative defense.\53\
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    \53\ Additionally, as discussed in section III.D.3., the title V
emergency affirmative defense provisions have rarely, if ever, been
asserted in enforcement proceedings. Thus, the EPA does not believe
that the removal of the narrowly drawn and apparently infrequently
used title V emergency affirmative defense provisions will have a
significant impact on sources.
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    Regarding specific comments concerning electric grid reliability,
the EPA does not believe that the current action will have a measurable
impact on electric grid reliability, and the EPA does not believe that
it is necessary to consult with other agencies with expertise in
reliability with respect to the limited actions being taken in this
rule. As an initial matter, even if the EPA were to retain the existing
title V emergency affirmative defense, the availability of that defense
in different types of situations involving issues of grid reliability
is uncertain. The EPA generally agrees with the commenters suggesting
that most electric grid reliability situations would not have qualified
as emergencies eligible for the title V affirmative defense, based on
the narrow definition of ``emergency'' in the title V regulations being
removed through this action.\54\ However, again, nothing would prevent
the consideration of reliability-related circumstances in determining
whether to initiate enforcement or in deciding whether penalties are
appropriate.
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    \54\ Again, the title V emergency provisions were only available
for ``sudden and reasonably unforeseeable events beyond the control
of the source'' requiring ``immediate corrective action to restore
normal operation, and that causes the source to exceed a technology-
based emission limitation under the permit, due to unavoidable
increases in emissions attributable to the emergency.'' 40 CFR
70.6(g)(1). This definition of ``emergency'' generally contemplated
emergencies directly affecting the operations of a single source. In
contrast, the need for one source to continue operating in response
to reliability concerns would generally not involve any sort of
emergency at that particular source, but rather would likely be
motivated by circumstances occurring at a different source. For
example, one source might be required to generate electricity to
make up for power that another source was unable to generate due to
an emergency at the other source.
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    Additionally, contrary to the assertion of commenters, the removal
of the affirmative defense provisions should not affect the ability of
electric grid operators to request that sources generate electricity in
order to avert grid reliability problems. Some of these comments were
based on the mistaken premise that the title V affirmative defense
provisions functioned as an exemption to emission limits.\55\ Moreover,
as other commenters note, Congress has provided various forms of relief
in these situations, including the amendment to FPA section 202(c)