Interstate Transport Plan Review for the 2015 8-hour Ozone NAAQS – Phase 2

The EPA is revisiting previous actions proposing or finalizing the disapproval or partial disapproval of certain State Implementation Plans and finalizing Federal Implementation Plans (FIPs) addressing states' interstate transport obligations under the 2015 ozone National Ambient Air Quality Standards (NAAQS). This proposed rule is designed to comport with Kentucky v. EPA, 123 F.4th 447 (6th Cir. 2024) and Texas v. EPA, 132 F.4th 808 (5th Cir. 2025).