ELR Citation: 54 ELR 20095
No(s). 23A349 (U.S. Jun 27, 2024)

The U.S. Supreme Court, 5-4, granted three states' and several industry groups' applications to stay enforcement of EPA's 2023 rule issuing a federal implementation plan (FIP) for 23 states whose SIPs the Agency determined had failed to adequately address new air quality standards for ozone levels under the CAA's "good neighbor" provision. EPA based the FIP on which emission control measures would maximize cost-effectiveness in improving ozone levels in downwind states and on the assumption the FIP would apply to all covered states. It also designed the plan to be severable, such that if any state dropped out, the plan would apply unchanged to the remaining states. Lower courts subsequently stayed 12 of the SIP disapprovals, precluding EPA from imposing the FIP on those states. The applicants challenged the FIP, arguing the decision to apply the plan after 12 states had "dropped out" was arbitrary and capricious, and sought to stay any effort to enforce the FIP against them pending appeal. The Court found EPA did not address whether and how measures found to maximize cost-effectiveness in achieving downwind ozone air quality improvements with the participation of 23 states would continue to do so when fewer states were subject to the plan, despite the concern having been raised during the public comment period. Finding the applicants were likely to succeed on their claim, it stayed enforcement of the rule pending disposition of petitions for review in the D.C. Circuit and any petitions for writ of certiorari. Gorsuch, J., delivered the opinion of the Court, in which Roberts, C.J., and Thomas, Alito, and Kavanaugh, JJ., joined. Barrett, J., filed a dissenting opinion, in which Sotomayor, Kagan, and Jackson, JJ., joined.