D.C Circuit Court Restores Title V Affirmative Defense

In a September 5, 2025 decision, the D.C. Circuit reinstated the affirmative defense provisions under Title V operating permits.  The court found that the July 1, 2023 rule, which removed the affirmative defense provisions from Title V permits, was arbitrary and capricious.  A key point in the court’s decision is that an affirmative defense to liability is not an exemption from an emissions standard that applies on a continuous basis.  The court reiterated that “[a]n affirmative defense allows a defendant to avoid liability, but it does not alter the underlying legal requirements,” which assume that a legal standard remains in force. The court also stated “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.”

The Title V affirmative defense provisions were first promulgated in 1992 under 40 CFR §70.6(g) to provide a defense for sources that exceed emissions limitations as a result of an emergency.  The rule created an affirmative defense regarding actions as a result of noncompliance with an emissions standard during an emergency.  Emergency was defined as “any situation arising from sudden and reasonably unforeseeable events beyond the control of the source, including acts of God…” and that results in unavoidable emissions in excess of a standard attributed to the emergency.  A permit holder would not be in violation of the Clean Air Act (CAA) if the affirmative defense provision applied. To qualify for the defense, the permittee was required to prove that an emergency occurred, the facility was being properly operated, and that all reasonable steps had been taken to minimize excess emissions during the emergency.

The affirmative defense provisions were removed from the Title V regulations by U.S. EPA on August 21, 2023 because they were deemed inconsistent with the U.S. EPA’s CAA enforcement structure and removal “would harmonize the EPA’s treatment of affirmative defenses across different CAA programs.”  The U.S. EPA also concluded that the affirmative defense provisions provided an exemption from emissions limits that otherwise applied continuously. They also stated that the affirmative defense encroached on the judiciary’s role to impose appropriate penalties.

In addition to reinstating the affirmative defense provisions that can be used by stationary sources, as applicable, in the event of unavoidable exceedances of emissions standards due to emergencies, the D.C. Circuit court ruling could provide additional leeway for the reinstatement or continuation (as applicable) of similar provisions under other regulatory programs. For example, U.S. EPA has been removing affirmative defense provisions added to Part 63 standards (National Emission Standards for Hazardous Air Pollutants for Source Categories, or NESHAPS) as they are conducting their periodic reviews.

ALL4’s air quality experts have significant experience developing Title V permitting and compliance strategies, and Title V air permit applications. Please reach out to me at rrakiewicz@all4inc.com or a familiar ALL4 resource should you have any questions about Title V permitting or compliance or for assistance in evaluating or permitting your next project.