Opinion Summary: Oklahoma v. EPA | Date Decided: 6/18/25 | Case No. 23–1067

This case was consolidated with: Pacificorp V. EPA, Case No. 23-1067.

Link to Docket: Here.

Background:

Under the Clean Air Act, each state must adopt an implementation plan to meet national standards, which EPA then reviews for compliance with the Act. In 2023, EPA published disapprovals of 21 states' plans implementing national ozone standards. It did so in a single Federal Register notice. The Act specifies that "[a] petition for review of the [EPA's] action in approving or promulgating any implementation plan ... or any other final action of the [EPA] under this Act ... which is locally or regionally applicable may be filed only in" the appropriate regional circuit, while "nationally applicable regulations ... may be filed only in" the D.C. Circuit. 42 U.S.C. § 7607(b)(1). Parties from a dozen states sought judicial review of their respective state plan disapprovals in their appropriate regional circuits.

The Fourth, Fifth, Sixth, and Eighth Circuits held that the implementation plan disapprovals of states within those circuits are appropriately challenged in their respective regional courts of appeals. In the decision below, the Tenth Circuit held that challenges to the disapprovals of Oklahoma's and Utah's plans can only be brought in the D.C. Circuit, explicitly disagreeing with the decisions of its sister circuits.

Questions Presented:

1. Whether a final action by EPA taken pursuant to its Clean Air Act authority with respect to a single state or region may be challenged only in the D.C. Circuit because EPA published the action in the same Federal Register notice as actions affecting other states or regions and claimed to use a consistent analysis for all states.
2. Whether the Environmental Protection Agency's disapproval of a State Implementation Plan may only be challenged in the D.C. Circuit under 42 U.S.C. § 7607 (b)(1) if EPA packages that disapproval with disapprovals of other States' SIPs and purports to use a consistent method in evaluating the state-specific determinations in those SIPs.

Holding: EPA's disapprovals of the Oklahoma and Utah SIPs are locally or regionally applicable actions reviewable in a regional Circuit.

Result: Reversed.

Voting Breakdown: 9-0. Justice Thomas delivered the opinion of the Court, in which Chief Justice Roberts and Justices Alito, Sotomayor, Kagan, Kavanaugh, Barrett and Jackson joined. Justice Gorsuch filed an opinion concurring in the judgment in which Chief Justice Roberts joined.

Link to Opinion: Here.

Oral Advocates:

• For Petitioners in 23-1067: Mithun Mansinghani, Oklahoma City, Okla.
• For Petitioners in 23-1068: Misha Tseytlin, Chicago, Ill.
• For Respondents: Malcolm L. Stewart, Deputy Solicitor General, Department of Justice, Washington, D.C.

Website Link to Oral Argument: Here.

Apple Podcast Link to Oral Argument: Here.