Back from the Dead? D.C. Circuit Resurrects Emergency Affirmative Defense to Title V Air Permit Noncompliance

Owners and operators of facilities subject to permitting under the Clean Air Act’s Title V permit program have cause for rejoicing. Title V permittees have just seen their fortunes improve, if only in a narrow way, with the resurrection of a key “emergency” affirmative defense to exceedances of technology-based emission limits set by their Title V permits.

The “emergency” affirmative defense, based on “any situation arising from sudden and reasonably unforeseeable events beyond the control of the source, including acts of God,” had been a mainstay of the Title permit program for over thirty years, but EPA rescinded it in 2023. However, in a September 5, 2025 ruling in SSM Litigation Group v. Environmental Protection Agency, the United States Circuit Court of Appeals for the District of Columbia (“D.C. Circuit”), held that EPA’s recission of the emergency affirmative defense was unlawful. In short, the D.C. Court found that EPA’s rationale for repealing the defense in 2023 was based on “erroneous legal justifications” and that more recent case law undermines EPA’s chief arguments.

When EPA promulgated the Title V permit program regulations, it included the emergency affirmative defense as a very limited but important means for the permittee to avoid regulatory liability for exceedances of technology-based emission limits included within a Title V permit. This defense, included in Title V permits issued by states that had been authorized by EPA to administer the Title V program or issued by EPA directly, provided an important excuse from meeting such limits due to “reasonably unforeseeable” circumstances over which the permitted did not have control, including, for example, acts of God. This meant that such an exceedance resulting from such factors as major storms, lightning strikes, power outages, or fires could be barred from noncompliance risk and liability, if such event were not reasonably foreseeable and beyond the permittee’s control and the permittee documented such factors and reported the emergency event.

With the SSM Litigation Group decision, Title V permittees have reason to believe that the emergency affirmative defense has been restored. This case was argued before the D.C. Circuit on January 14, 2025, in the last week of the Biden Administration, and EPA defended its repeal of the emergency affirmative defense, along with some environmental groups. It seems less likely that a Trump Administration EPA would appeal this decision even though it restores a defense to enforcement action. Still, should the policy directive at EPA change again during a following administration, EPA could change its mind and again seek to unwind the defense or make it even narrower.

There are several other cautionary points to consider as well. First, this decision could yet be appealed by environmental groups that were involved in the case, or a request for rehearing by all of the active judges of the D.C. Circuit could be sought, so the case may not be fully over and final in its effect.

Second, EPA will still need to amend its own regulations to adhere to the D.C. Circuit’s decision (assuming it stands), and many states will likely follow suit, but perhaps not all. Restoration of the emergency affirmative defense to the federal Title V regulations does not mean that states implementing the Title V permit program will automatically restore the emergency affirmative defense in their own regulations after repealing it to comport their respective programs with the federal program. States are allowed by the Clean Air Act to be more stringent than the federal Title V permit program, and some may choose not to reinstitute the defense within their state Title V permit program.

Third, the emergency affirmative defense is conditional and requires that the permittee carry the burden of proof in mounting such defense and demonstrate eligibility of the technology-based limitation under the defense’s criteria as discussed above and to maintain the proper documentation of related events. While the burden on the permittee is as it has always been, these criteria bear repeating as the defense appears available once again:

• “An emergency shall not include noncompliance to the extent caused by improperly designed equipment, lack of preventative maintenance, careless or improper operation, or operator error;”
• “An emergency occurred and . . . the permittee can identify the cause(s) of the emergency;”
• “The permitted facility was at the time being properly operated;”
• “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
• “The permittee submitted notice of the emergency to the permitting authority within 2 working days of the time when emission limitations were exceeded due to the emergency, [which] notice must contain a description of the emergency, any steps taken to mitigate emissions, and corrective actions taken.”

57 Fed. Reg. 32250, 32306 (July 21, 1992); 61 Fed. Reg. 34202, 34239 (July 1, 1996)

Title V permit holders can find good news in the SSM Litigation Group decision, even if it is of limited scope given the breadth of Title V permit obligations and compliance risks. Permittees now need to watch for any challenge of the decision by environmental groups and next steps by EPA restate the emergency affirmative defense into the Title V program regulations and which states follow EPA’s lead and so the same for their state-level Title V program implementation.

SSM Litigation Group v. EPA, No. 23-1267, 2025 WL 2552531 (D.C. Cir. Sept. 5, 2025)
Operating Permit Program, 57 Fed. Reg. 32250, 32306 (July 21, 1992) (providing emergency affirmative defense as part of state-issued Title V permits), codified at 40 C.F.R. § 70.6(g)
Federal Operating Permits Program, 61 Fed. Reg. 34202, 34239 (July 1, 1996) (providing emergency affirmative defense as part of EPA-issued Title V permits), codified at 40 C.F.R. § 71.6(g)
Removal of Title V Emergency Affirmative Defense Provisions From State Operating Permit Programs and Federal Operating Permit Program, 88 Fed. Reg. 47029 (August 21, 2023)