Ssm Litigation Group v. Environmental Protection Agency

FOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued January 14, 2025 Decided September 5, 2025
No. 23-1267
SSM LITIGATION GROUP,
PETITIONER
v.
ENVIRONMENTAL PROTECTION AGENCY,
RESPONDENT
CALIFORNIA COMMUNITIES AGAINST TOXICS, ET AL.,
INTERVENORS
On Petition for Review of a Final Action
of the Environmental Protection Agency
Russell S. Frye argued the cause and filed the briefs for
petitioner.
Daniel R. Dertke, Attorney, U.S. Department of Justice,
argued the cause for respondent. With him on the brief was
Todd Kim, Assistant Attorney General.
Joshua Smith, Andrea Issod, Deena Tumeh, Seth L.
Johnson, Patton Dycus, John D. Walke, and Emily K. Davis

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were on the brief for environmental intervenors in support of
respondent.
Before: RAO and WALKER, Circuit Judges, and GINSBURG,
Senior Circuit Judge.
Opinion for the Court filed by Circuit Judge RAO.
RAO, Circuit Judge: Pollution control technology
sometimes fails due to an emergency or other unforeseen event.
During such emergencies, a stationary source of air pollution
may exceed its emission limitations. For decades, the
Environmental Protection Agency recognized this reality by
providing an affirmative defense to liability for excess
emissions caused by emergency events. In 2023, the agency
rescinded the defense, concluding it was unlawful because it
encroached on the judiciary’s authority under the Clean Air Act
to impose “appropriate civil penalties.” 42 U.S.C. § 7604(a). In
addition, EPA maintained the defense was unlawful because it
could be construed as an exemption that rendered emission
standards non-continuous in violation of the Clean Air Act.
In its petition for review, SSM Litigation Group argues
EPA’s rescission of the Title V affirmative defense was
arbitrary and capricious because it rests entirely on erroneous
legal justifications. We agree and therefore grant the petition.
I.
The Clean Air Act authorizes EPA to impose emission
standards and limitations for various sources of air pollution,
including factories and power plants. The Act defines an
emission limitation as “a requirement … which limits the
quantity, rate, or concentration of emissions of air pollutants on
a continuous basis.” 42 U.S.C. § 7602(k). As relevant here,

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EPA sets emission limitations based on the capabilities of
pollution control technology. See, e.g., id. §§ 7411, 7412. Title
V of the Clean Air Act, enacted in 1990, establishes a
permitting regime for facilities that emit air pollution. Id.
§§ 7661 et seq. This regime “consolidate[d] existing air
pollution requirements into a single document, the Title V
permit.” U.S. Sugar Corp. v. EPA, 830 F.3d 579, 597 (D.C. Cir.
2016) (cleaned up).
All operators of stationary sources of air pollution are
required to apply for and hold a Title V permit, which must list
the “enforceable emission limitations and standards”
applicable to the source under the Clean Air Act. 42 U.S.C.
§ 7661c(a); see id. § 7661a(a). If an operator violates the
emission limitations and standards incorporated in its permit,
the operator can be sued for injunctive relief and “any
appropriate civil penalties.” Id. § 7604(a); see id. § 7413(b).
But the permit also creates a “shield” from liability that treats
compliance with the permit’s terms as compliance with
applicable Clean Air Act requirements. Id. § 7661c(f).
Shortly after Congress enacted Title V, EPA promulgated
regulations that created a narrow defense for stationary sources
that exceed their emission limitations due to an emergency
event. See 57 Fed. Reg. 32250, 32306 (1992) (establishing
affirmative defense for holders of state-issued Title V permits);
61 Fed. Reg. 34202, 34239 (1996) (extending affirmative
defense to holders of federally issued permits). These
regulations created “an affirmative defense to an action brought
for noncompliance with … technology-based emission
limitations” during an emergency. 40 C.F.R. § 70.6(g)(2)
(2022). The regulations defined an emergency as “any situation
arising from sudden and reasonably unforeseeable events
beyond the control of the source, including acts of God,” that
“causes the source to exceed a technology-based emission

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limitation under the permit, due to unavoidable increases in
emissions attributable to the emergency.” Id. § 70.6(g)(1)
(2022). To qualify for the defense, the permittee was required
to prove that “[a]n emergency occurred,” that the facility was
“being properly operated,” and that the permittee had taken “all
reasonable steps” to minimize excess emissions during the
emergency. Id. § 70.6(g)(3) (2022). If the defense applied, a
permittee would not be found in violation of the Clean Air Act
for exceeding its emission limitations. Id. § 70.6(g)(2) (2022).
For decades, EPA retained the Title V affirmative defense
for emergencies. In 2016, however, EPA proposed rescinding
the defense on the ground that it unlawfully encroached on the
judiciary’s role to impose “any appropriate civil penalties” for
Clean Air Act violations. 42 U.S.C. § 7604(a); see 81 Fed. Reg.
38645, 38648–49 (2016) (discussing NRDC v. EPA, 749 F.3d
1055 (D.C. Cir. 2014)). In the alternative, EPA concluded the
defense was unlawful because it operated as an exemption from
otherwise applicable emission limitations, rendering those
limitations non-continuous in violation of 42 U.S.C. § 7602(k).
81 Fed. Reg. at 38648 n.12 (discussing Sierra Club v. EPA, 551
F.3d 1019 (D.C. Cir. 2008)). EPA rescinded the defense in a
final rule issued in 2023. 88 Fed. Reg. 47029, 47030–31
(2023).
SSM Litigation Group (“SSM”), a coalition of trade
associations some of whose members operate stationary
sources of air pollution and hold Title V permits, petitioned for
review.
II.
We begin, as we must, with our jurisdiction. We have
exclusive jurisdiction over petitions challenging “any …
nationally applicable regulations promulgated, or final action
taken, by the [EPA] Administrator.” 42 U.S.C. § 7607(b). The

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government and environmental intervenors maintain that SSM
has failed to demonstrate standing. Because SSM is an
association ultimately representing entities directly regulated
under Title V, we conclude it has standing to challenge the
rescission of the Title V affirmative defense.
A.
To demonstrate associational standing, “an organization
must show that (1) its members would otherwise have standing
to sue in their own right; (2) the interests it seeks to protect are
germane to the organization’s purpose; and (3) neither the
claim asserted nor the relief requested requires the participation
of individual members in the lawsuit.” Int’l Dark-Sky Ass’n,
Inc. v. FCC, 106 F.4th 1206, 1217 (D.C. Cir. 2024) (cleaned
up). At the time SSM submitted its petition, the D.C. Circuit
Rules required a direct review petitioner to “set forth the basis
for the claim of standing” in its opening brief and, if standing
is not apparent from the administrative record, to establish
standing through “arguments and evidence.”1 D.C. Cir. R.
28(a)(7) (2024). In applying this rule, we have “allowed
petitioners to proceed if a reply brief fleshes out a timely raised
theory of standing and also makes standing patently obvious
and irrefutable.” Sierra Club v. U.S. Dep’t of Energy, 107 F.4th
1012, 1015 (D.C. Cir. 2024) (cleaned up).
B.
The parties do not dispute that the interests SSM seeks to
protect are germane to its purpose or that the claim asserted and
relief sought—reversal of a rule—do not require the
1 D.C. Circuit Rule 28(a)(7) has since been amended, effective
August 11, 2025, to require all petitioners to include, in their opening
briefs, arguments and evidence establishing standing, regardless of
whether standing is apparent from the administrative record.

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participation of individual members. Int’l Dark-Sky Ass’n, 106
F.4th at 1217. They disagree only over whether SSM has
demonstrated, in accordance with our local rules, that it has
members that would have standing to sue in their own right.
We conclude SSM has made this showing.
SSM raised a straightforward theory of standing in its
opening brief. It explained that it is a coalition of trade
associations “whose members operate stationary sources of air
pollution subject to operating permits issued under [Clean Air
Act] Title V” and who were protected “under an affirmative
defense provision” for emergencies. SSM Br. at 18. In other
words, SSM’s member associations have members that are
directly regulated under Title V and that have been exposed to
liability by EPA’s rescission of the affirmative defense
included in their permits. That injury is redressable by an order
of this court setting aside the rescission regulation.
Neither EPA nor intervenors question that a holder of a
Title V permit would have standing to sue if its permit included
the affirmative defense. EPA argues only that SSM failed to
provide evidence that it represents such permit holders. To be
sure, SSM neglected in its opening brief to attach declarations
from any member association, instead providing those
declarations only in its reply brief. But that delay in providing
evidence of standing is excusable because (1) the
administrative record “went a long way toward showing
standing”; (2) the reply brief declarations did not raise a new
theory of standing and made standing “patently obvious”; and
(3) EPA “suffered no prejudice” from the delay. Nat’l Council
for Adoption v. Blinken, 4 F.4th 106, 112 (D.C. Cir. 2021).
First, when filing its petition, SSM reasonably concluded
the administrative record was sufficient to establish its
standing. As SSM pointed out in its opening brief, numerous

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commenters in the rulemaking process raised a similar theory
of injury caused by the rescission of the affirmative defense.
See, e.g., J.A. 55 (comment by Ohio Chemistry Technology
Council, et al., explaining its “members are subject to
regulation by Ohio’s … fully-approved Title V operating
permit program, and have a direct and substantial interest in the
action proposed by EPA”); J.A. 59 (comment by a trade
association explaining its “members own and operate
manufacturing facilities … affected by the proposed change in
the operating permit program regulations because they are
required to have [Clean Air Act] operating permits”). At the
time SSM filed its petition, Circuit Rule 28(a)(7) required
evidence of standing only when standing was “not apparent
from the administrative record.” D.C. Cir. R. 28(a)(7) (2024).
But the record here demonstrates that directly regulated Title
V permit holders are injured by the rescission—an entirely
obvious and straightforward theory of standing.
SSM’s reliance on the administrative record in its opening
brief was reasonable, particularly because the requirement that
an association identify specific members is most salient when
an association represents third parties who are not directly
regulated. See, e.g., Sierra Club v. EPA, 292 F.3d 895, 901–02
(D.C. Cir. 2002) (evaluating whether individuals had standing
to challenge rule regulating facilities generating or treating
toxic wastewater); Chamber of Commerce v. EPA, 642 F.3d
192, 200–10 (D.C. Cir. 2011) (evaluating whether automobile
dealers had standing to challenge rule regulating automobile
manufacturers); Twin Rivers Paper Co. LLC v. SEC, 934 F.3d
607, 613–14 (D.C. Cir. 2019) (evaluating whether retirees had
standing to challenge rule regulating investment funds). SSM
asserted its members represent directly regulated Title V permit
holders, and the explanation of why such directly regulated
entities have standing is clearly established by the
administrative record.

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Second, although SSM did not identify specific regulated
entities in its opening brief, it provided the necessary
declarations in its reply brief, which “ma[de] standing patently
obvious and irrefutable.” Dep’t of Energy, 107 F.4th at 1015
(cleaned up). In its reply brief, SSM attached declarations from
member associations that corroborated its original theory of
standing. For example, the American Chemistry Council
attested that it is part of SSM and that its members “have
facilities required to have an operating permit under Title V of
the Clean Air Act,” some of which “are located in states that
had approved state Title V permitting programs that contained
Title V affirmative defense provisions.” Reply Br., Ex. B.,
Decl. of Dr. Kimberly White. The American Forest and Paper
Association attested to similar facts. See Reply Br., Ex. A,
Decl. of Timothy Hunt (attesting the Title V affirmative
defense “had been either stated in or incorporated by reference
in” the Title V permits “that some or all” of the associations’
members’ are required to have). These declarations make
standing patently obvious and irrefutable because they confirm
that the facilities SSM ultimately represents are “object[s] of
the action (or forgone action) at issue.” Lujan v. Defs. of
Wildlife, 504 U.S. 555, 561 (1992).
At oral argument, EPA suggested the reply brief
declarations were deficient because they failed to name
individual facilities. Our precedents are clear, however, that
“anonymity is no barrier to standing on this record” because
SSM’s members are “directly regulated by the … [r]ule” and
naming them would “add[] no essential information bearing on
the injury component of standing.” Advocs. for Highway &
Auto Safety v. Fed. Motor Carrier Safety Admin., 41 F.4th 586,
594 (D.C. Cir. 2022) (cleaned up). EPA does not, and cannot,
maintain that a directly regulated facility protected by the
affirmative defense lacks standing to challenge its rescission.
And there is no serious dispute that SSM’s reply brief

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declarations—made under penalty of perjury—establish that
SSM represents such facilities.
Finally, because SSM’s standing is irrefutable and the
reply brief declarations merely bolster its original theory of
standing, EPA “was not prejudiced by its inability to respond
to the supplemental declarations.” Cmtys. Against Runway
Expansion, Inc. v. FAA, 355 F.3d 678, 685 (D.C. Cir. 2004);
see also Dep’t of Energy, 107 F.4th at 1015 (same). We may
consider these reply brief declarations, which conclusively
establish that SSM has associational standing.
III.
On the merits, we conclude EPA’s rescission of the
affirmative defense was not reasonably explained and not in
accordance with law. See 42 U.S.C. § 7607(d)(9)(A)
(authorizing reviewing court to “reverse any … action found to
be … arbitrary, capricious, an abuse of discretion, or otherwise
not in accordance with law”); Ethyl Corp. v. EPA, 51 F.3d
1053, 1064 (D.C. Cir. 1995) (explaining the Clean Air Act’s
standard of review “is essentially the same” as that of the
Administrative Procedure Act). The agency justified its
rescission exclusively on legal grounds, asserting the Title V
affirmative defense was unlawful for two alternative reasons.
First, EPA primarily maintained the affirmative defense
encroached on the judiciary’s statutory authority to assess civil
penalties. In the alternative, EPA stated the defense functioned
as an exemption that rendered emission limitations non-
continuous in violation of the Clean Air Act. Because the

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agency’s rescission regulation was premised entirely on
erroneous legal justifications, it must be reversed.
A.
EPA justified its rescission of the Title V affirmative
defense primarily on the ground that the defense unlawfully
encroached on the judiciary’s role under the Clean Air Act to
assess penalties for violations of emission limitations. See 88
Fed. Reg. at 47030–34. EPA based this conclusion on NRDC
v. EPA, which held that a partial affirmative defense to
monetary penalties unlawfully restricted the judiciary’s
statutory authority to impose “appropriate civil penalties.” 749
F.3d at 1063 (quoting 42 U.S.C. § 7604(a)). EPA now
concedes—and the environmental intervenors largely do not
dispute—that the primary rationale for the rescission has been
foreclosed by our intervening decision in Environmental
Committee of Florida Electric Power Coordinating Group,
Inc. v. EPA, 94 F.4th 77 (D.C. Cir. 2024) (“Florida Electric”).
In Florida Electric, we clarified the critical distinction
between a true affirmative defense that operates as a complete
defense to Clean Air Act liability—as does the Title V defense
for emergencies—and an affirmative defense that merely
“precludes certain remedies after a source has violated an
emission rule.” Id. at 114. The latter is better understood as a
limitation on remedies. Id. at 86 (discussing different types of
affirmative defenses). Under the Clean Air Act, the EPA has
no authority to create a regulatory “defense” that limits the
remedial authority granted by Congress to the federal courts.
Id. at 114–15. But a complete affirmative defense, like the one
at issue here, is permissible because it relates to the antecedent
question of liability and therefore does not impinge on the
judiciary’s authority to award “appropriate civil penalties.” 42
U.S.C. § 7604(a).

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Because the Title V affirmative defense is a complete
defense to liability, not a limitation on judicial remedies, EPA’s
primary rationale for its rescission was erroneous.
B.
EPA and the environmental intervenors also defend the
rescission regulation on the ground that the Title V affirmative
defense is effectively an exemption from applicable emission
limitations and therefore renders those limitations not
“continuous” in violation of the Clean Air Act, as interpreted
by this court in Sierra Club v. EPA, 551 F.3d at 1027–28. This
rationale finds no support in the Clean Air Act or Sierra Club.
The Clean Air Act requires EPA to establish emission
standards. See, e.g., 42 U.S.C. § 7412(d). And the Act defines
an emission standard or limitation as a requirement that “limits
the quantity, rate, or concentration of emissions of air
pollutants on a continuous basis.” Id. § 7602(k) (emphasis
added). Reading these provisions together in a case involving
section 112 standards, we interpreted the Clean Air Act to
require “that some section 112 standard apply continuously.”
Sierra Club, 551 F.3d at 1028. We held that a regulation that
expressly lifted section 112 standards during periods of startup,
shutdown, and malfunction was contrary to the Act. Id.
The reasoning of Sierra Club, however, does not support
EPA’s contention that the Title V affirmative defense is
unlawful. The agency’s argument conflates two distinct legal
concepts: an affirmative defense to liability and an ex ante
exemption from an emission standard. An affirmative defense
allows a defendant to avoid liability, but it does not alter the
underlying legal requirements.2 See Wright & Miller, 5 Fed.
2 The concept of an affirmative defense derives from the common
law pleading device known as confession and avoidance. See

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Prac. & Proc. Civ. § 1270 (4th ed. updated May 2025). The
very concept of an affirmative defense assumes that a legal
standard remains in force, because otherwise there would be no
claim—and no need for an affirmative defense. See Wright v.
Southland Corp., 187 F.3d 1287, 1303 (11th Cir. 1999) (“An
affirmative defense is generally a defense that, if established,
requires judgment for the defendant even if the plaintiff can
prove his case.”). Unlike the regulatory exemption in Sierra
Club, which suspended emission standards during certain
times, the Title V affirmative defense for emergencies does not
lift applicable standards. Because the emission standards are
never lifted, they apply “on a continuous basis” as required by
the Clean Air Act. 42 U.S.C. § 7602(k).
EPA leans on the fact that in Florida Electric we described
complete affirmative defenses as “creat[ing] an exemption
from the normal emission rule” and as “functionally
exemptions.” 94 F.4th at 114, 116. Those descriptions,
however, were necessary only to distinguish complete
affirmatives defenses from partial affirmative defenses—and
to explain why the complete affirmative defenses did not
encroach on the judiciary’s power to choose appropriate
remedies for a Clean Air Act violation. Id. at 114. We did not
otherwise collapse the legal distinction between an affirmative
defense and an ex ante exemption from a legal standard. And,
as EPA acknowledges in its brief, Florida Electric did not
reach the question of whether a complete affirmative defense
Shipman, Common-Law Pleading § 166, p. 299–301 (3d ed. 1923).
Confession and avoidance contrasts with demurrer, which is an
assertion that a claim is legally insufficient on its own terms. See id.
§§ 146–47, p. 277–79. Today, litigants make such insufficiency
assertions through a motion to dismiss, Fed R. Civ. P. 12(b)(6),
whereas affirmative defenses must typically be raised in a responsive
pleading, Fed R. Civ. P. 8(c)(1).

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would render an emission limitation non-continuous in
violation of the Clean Air Act. See id.; EPA Br. at 40.
Squarely presented with that question, we now hold that a
complete affirmative defense to liability does not render an
emission limitation non-continuous under 42 U.S.C. § 7602(k).
EPA therefore cannot justify its rescission of the Title V
affirmative defense on the ground that it renders emission
limitations non-continuous.
* * *
EPA rescinded a thirty-year-old affirmative defense on the
ground that it was unlawful under the Clean Air Act. EPA’s
reasoning, however, cannot be squared with the text of the
Clean Air Act or our precedents. Because EPA offered no
independent policy rationale, its rescission regulation was
unreasonable and not in accordance with law. We therefore
grant the petition and reverse the rescission.
So ordered.

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