EPA Restores Title V Affirmative Defense Protections

On June 1, 2026, the Environmental Protection Agency (“EPA”) issued a final rule withdrawing a 2023 rule, Removal of Title V Emergency Affirmative Defense Provisions From State Operating Permit Programs and Federal Operating Permit Program (the “2023 Affirmative Defense Rule”). The withdrawal reinstates the longstanding emergency-related affirmative defense provisions in the EPA’s Title V operating permit program that shield regulated entities against claims for noncompliance with technology-based emission limitations during an emergency.

Background

Title V of the Clean Air Act (“CAA”), enacted in 1990, establishes a permitting regime for facilities that emit air pollution.¹ Under this framework, 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 CAA.² 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.”³ Subsequent regulations, however, created “an affirmative defense to an action brought for noncompliance with . . . technology-based emission limitations” during an emergency.⁴ Those provisions had defined an “emergency” 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.”⁵

On July 21, 2023, the EPA issued the 2023 Affirmative Defense Rule, which rescinded the emergency-related affirmative defense provisions based on the EPA’s conclusion that they were legally impermissible under the CAA.⁶ As a consequence, states were likewise required to remove from their operating permit program regulations and existing operating permits any State affirmative defense provisions based on the rescinded Federal provisions.⁷

The DC Circuit’s Decision in SSM Litigation Group v. EPA

SSM Litigation Group filed a petition for review of the 2023 Affirmative Defense Rule in the US Court of Appeals for the DC Circuit. On September 5, 2025, the court issued its decision in SSM Litig. Grp. v. EPA, 150 F.4th 593 (D.C. Cir. 2025), finding that the EPA’s 2023 Affirmative Defense Rule was “unreasonable and not in accordance with law” and rested “entirely on erroneous legal justifications.”⁸ The court issued its mandate on January 12, 2026, after denying a petition for rehearing on January 2, 2026.

The Withdrawal

Following the DC Circuit’s decision, the EPA has now formally withdrawn the 2023 Affirmative Defense Rule. The effect of this final action is to restore the text of 40 CFR 70.6(g) and 71.6(g) as those provisions existed before the 2023 rule—that is, to reinstate the emergency-related affirmative defense provisions in their entirety.

The EPA issued this action as a final rule without notice-and-comment rulemaking, invoking the Administrative Procedure Act’s “good cause” exemption under 5 U.S.C. 553(b)(B). The Agency determined that providing a public hearing or an opportunity for comment was unnecessary because the withdrawal is a “ministerial act necessary to carry out the D.C. Circuit’s mandate” involving “no exercise of Agency discretion.” For the same reasons, the EPA invoked good cause under 5 U.S.C. 553(d)(3) to make the rule effective immediately upon publication in the Federal Register.

The EPA also characterized this action as an Executive Order 14192 deregulatory action,⁹ noting that it provides burden reduction because State, local, and Tribal permitting authorities are no longer required to submit revisions to their Title V operating permit programs or to revise existing operating permits.

Reinstated Emergency Affirmative Defense Provisions

With the withdrawal now effective, the emergency affirmative defense at 40 CFR 70.6(g) and 71.6(g) is once again available to permittees. Under the reinstated provisions, a permittee may assert the affirmative defense in an enforcement proceeding for noncompliance with technology-based emission limitations if it demonstrates through properly signed, contemporaneous operating logs or other relevant evidence that:

1. An emergency occurred and the permittee can identify the cause(s) of the emergency;
2. The permitted facility was at the time being properly operated;
3. During the period of the emergency, the permittee took all reasonable steps to minimize levels of emissions that exceeded the emission standards or other requirements in the permit; and
4. The permittee submitted notice of the emergency to the permitting authority within two working days of the time when emission limitations were exceeded due to the emergency, including a description of the emergency, any steps taken to mitigate emissions, and corrective actions taken.¹⁰

The permittee bears the burden of proof in establishing the occurrence of an emergency. Importantly, the definition of “emergency” does not include noncompliance caused by improperly designed equipment, lack of preventive maintenance, careless or improper operation, or operator error.

Practical Implications

This withdrawal carries several implications for regulated entities and State permitting authorities:

State and local program revisions are no longer required. State, local, and Tribal permitting authorities are no longer required to submit revisions to their Title V operating permit programs or to revise existing operating permits to implement the requirements of the now-withdrawn 2023 rule. Jurisdictions that had already removed or modified their emergency affirmative defense provisions to comply with the 2023 rule will consider reinstating them.

Affirmative defense is available again. Owners and operators of sources holding Title V operating permits once again have access to the emergency affirmative defense for exceedances of technology-based emission limitations resulting from qualifying emergencies. This restoration of the regulatory status quo provides significant operational certainty for facilities that may experience sudden, unforeseeable disruptions.

Documentation is critical. Because the affirmative defense must be demonstrated through properly signed, contemporaneous operating logs or other relevant evidence, facilities should ensure that their emergency response protocols include real-time documentation of emergency events, the actions taken to minimize excess emissions, and timely notification to the permitting authority.

Conclusion

The EPA’s withdrawal of the 2023 Affirmative Defense Rule marks a return to the longstanding regulatory framework under which permittees may assert an emergency affirmative defense against enforcement actions for exceedances of technology-based emission limitations. Regulated entities should review their operating procedures to ensure they are positioned to take advantage of the reinstated provisions, with particular attention to contemporaneous documentation and timely notification requirements. Mayer Brown will continue to monitor developments in this space, including any potential challenges to the withdrawal itself.

 

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¹ 42 U.S.C. § 7661 et seq.

² Id. § 7661c(a).

³ Id. § 7413(b).

⁴ 40 C.F.R. § 70.6(g)(2); 40 C.F.R. § 71.6(g)(2).

⁵ 40 C.F.R. § 70.6(g)(1); 40 C.F.R. § 71.6(g)(1).

⁶ Removal of Title V Emergency Affirmative Defense Provisions From State Operating Permit Programs and Federal Operating Permit Program, 88 Fed. Reg. 47,029 (July 21, 2023).

⁷ Id.

⁸ SSM Litig. Grp. v. Env’t Prot. Agency, 150 F.4th 593, 599-600 (D.C. Cir. 2025).

⁹“ Unleashing Prosperity Through Deregulation,” Exec. Order No. 14192, 90 FR 9065 (Jan. 31, 2025).

¹⁰ 40 C.F.R. § 70.6(g)(3); 40 C.F.R. § 71.6(g)(3).