This article serves as an update to the July 22, 2025, article: Indiana Air Regulation Updates for Affirmative Defense Provisions.
On July 21, 2023, the U.S. Environmental Protection Agency (EPA) finalized the removal of the “emergency” affirmative defense from the Clean Air Act operating permit program regulations. The emergency affirmative defense provision had previously been part of the Clean Air Act operating permit program for decades. It was designed to balance strict compliance requirements with practical day-to-day operations at industrial facilities, recognizing that certain emergencies are beyond a facility’s control. Affirmative defense allowed facilities to avoid penalties for certain violations caused by sudden, unforeseeable emergencies outside of the facility’s control (i.e., natural disasters), provided specific conditions were met. EPA’s removal of these provisions was intended to ensure continuous compliance with emission limits (even during periods of startup, shutdown, and malfunction) and to avoid what the agency viewed as an improper limitation on enforcement authority. The removal reflected a shift towards stricter enforcement.
In response, effective June 21, 2025, the Indiana Department of Environmental Management (IDEM) amended 326 IAC 2-7 (Part 70 Permit Program) and 326 IAC 2-8 (Federal Enforceable State Operating Permit Program) to remove emergency affirmative defense language and restore malfunction reporting requirements under 326 IAC 1-6 (Malfunctions). These amendments triggered a statewide permit reopening campaign, where IDEM began administratively opening existing Part 70 and FESOP permits to remove the emergency affirmative defense provisions and add the malfunction requirements. This process was expected to take several years, according to guidance from IDEM.
Industry Impact
Under the malfunction rule (326 IAC 1-6), facilities must record all malfunctions, startups, or shutdowns that cause violations of applicable air pollution control regulations or emission limits. If the malfunction lasts longer than one (1) hour, the facility must notify IDEM as soon as possible but not more than four (4) daytime business hours. Failure to report would constitute a violation of the rule, and a permit deviation once the facility’s permit is updated to include the malfunction rule per IDEM’s reopening campaign. The malfunction reporting requirements impose significant challenges for facilities because they demand rapid response to IDEM and diligent documentation during what is expected to be a chaotic time of operational disruption. Having to notify IDEM as soon as possible if a malfunction lasts longer than one (1) hour can be logistically challenging when diagnosing the problem and assessing regulatory impacts can take time. This is a particular challenge for power plants, refineries, data centers, and other manufacturing facilities where sudden upsets and malfunctions may occur more frequently. Additionally, the requirement to maintain records of all malfunctions, startups, and shutdowns adds administrative burden and increases the risk of noncompliance due to human error, particularly for facilities with limited environmental staff.
July 21, 2023 Rule Reversal
On September 5, 2025, the U.S. Court of Appeals for the D.C. Circuit issued a decision reversing EPA’s July 21, 2023 rule (SSM Litigation Group v. EPA, Case No. 23-1267). The court held that the emergency affirmative defense is permissible under the Clean Air Act because it does not impede continuous compliance requirements. The court found that the defense provides a lawful process for facilities to demonstrate that certain violations caused by unforeseen emergencies should not result in enforceable penalties when the facility was otherwise complying with all regulatory conditions. The reversal reflects the court’s position that facilities should not be penalized for certain unforeseeable events. This ruling reinstates the emergency affirmative defense nationwide and requires EPA to revise its regulations accordingly. EPA will need to reverse the 2023 rule to reinstate the emergency affirmative defense language. Indiana will likely follow suit by amending the Part 70 and FESOP programs to reinstate emergency affirmative defense, and likewise, add it back to Part 70 and FESOP permits.
What’s Next?
Despite the court ruling, the current Part 70 and FESOP rules in the Indiana rules remain in effect until new rulemakings occur, and IDEM has not provided a timeline for rulemaking to reinstate affirmative defense. Based on typical regulatory processes, IDEM will likely not provide an update until after EPA does. Once EPA revises its regulations, IDEM will need to begin the rulemaking process for reinstating the defense language, which involves drafting the amended defense language, publishing notices, soliciting public comments, and obtaining Environmental Rules Board approval. Needless to say, the reinstatement of the emergency affirmative defense language in 326 IAC 2-7 and 326 IAC 2-8 is not a fast process.
Additionally, IDEM has yet to announce any changes to its ongoing permit reopening campaign. IDEM may pause reopening Part 70 and FESOP permits to remove emergency provisions, but no formal statement has been issued.
For facilities operating under a Part 70 or FESOP permit, this creates a temporary compliance challenge. While the defense is technically reinstated at the federal level, Indiana’s current rules do not reflect that change, and many Part 70 and FESOP permits across the state have already had their emergency provisions removed. Even for facilities that have not yet had the emergency provisions removed from their Part 70 and FESOP permits, since the emergency provisions are not currently included in the Part 70 and FESOP regulations, IDEM may not honor the emergency defense during an enforcement action. Therefore, the emergency defense should not be utilized in enforcement actions until IDEM completes its rulemaking to add the emergency provisions back into the Part 70 and FESOP regulations. This could result in facilities mistakenly assuming they are protected under the defense and fail to meet the malfunction reporting obligations under 326 IAC 1-6, leading to potential violations. To maintain compliance during this transition period, it is recommended that facilities comply with IDEM’s existing requirements, including recording and reporting malfunctions under 326 IAC 1-6.
If you have any questions about how these developments affect your facility or need assistance preparing for upcoming changes, please contact Trinity’s Indiana office or call 317-451-8100.
