EPA is removing the "emergency" affirmative defense provisions from the EPA's title V operating permit program regulations. These provisions established an affirmative defense that sources could have asserted in enforcement cases brought for noncompliance with technology-based emission limitations in operating permits, provided that the exceedances occurred due to qualifying emergency circumstances. These provisions are being removed because they are inconsistent with the EPA's interpretation of the enforcement structure of the CAA in light of prior court decisions from the U.S. Court of Appeals for the D.C. Circuit. Through this document, the EPA is also providing guidance on the implementation process resulting from the removal of the emergency affirmative defense provisions from the EPA's regulations, including the need for some state, local, and tribal permitting authorities to submit program revisions to the EPA to remove similar title V affirmative defense provisions from their EPA-approved title V programs, and to remove similar provisions from individual operating permits. This final rule is effective on 21 August 2023. POC is Corey Sugerik, Office of Air Quality Planning and Standards, Air Quality Policy Division (C504–05), EPA tele (919) 541–3223; email sugerik.corey@epa.gov.(Federal Register 21 July 2023 [Final Rule] Page 47029-47054)