605 U.S. 609 (2025) · 2025
Oklahoma v. EPA
environmental lawClean Air ActEPAair pollutionvenuefederalismLandmark
Summary
Oklahoma v. EPA held that EPA disapprovals of state implementation plans are locally or regionally applicable actions under the Clean Air Act. Challenges to those disapprovals therefore belong in regional courts of appeals rather than automatically in the D.C. Circuit. The case leaves the merits of EPA's disapprovals for the proper courts.
Background & Context
States must submit implementation plans showing how they will meet federal air-quality standards. EPA disapproved several state plans related to ozone pollution. Oklahoma and other parties challenged those disapprovals and disputed whether the D.C. Circuit or regional circuits had venue.
The Question Before the Court
Under the Clean Air Act, are EPA disapprovals of state implementation plans nationally applicable actions, or locally or regionally applicable actions that may be challenged in regional courts?
Petitioner
Oklahoma, et al.
Party asking the Court to review or reverse
Argued
- The disapprovals were regional actions.
Respondent
Environmental Protection Agency, et al.
Party defending the judgment below
Argued
- The disputes belonged in the D.C. Circuit.
The Holding
EPA disapprovals of state implementation plans under the Clean Air Act are locally or regionally applicable actions, so challenges to them belong in regional circuits, not exclusively in the D.C. Circuit.
The Court
How the justices lined up in this decision.
6-0, with Justice Alito not participating
Vote
Joined decision
6 justicesAC
Amy Barrett
Majority
BK
Brett Kavanaugh
Majority
CT
Clarence Thomas
Majority
EK
Elena Kagan
Majority
KB
Ketanji Jackson
Majority
SS
Sonia Sotomayor
Majority
Concurred
2 justicesJR
John Roberts
Concurred
NG
Neil Gorsuch
Concurred
What this means for you
The ruling lets states and regulated parties challenge some EPA air decisions in regional courts closer to the affected states. That can shape forum choice in environmental litigation and may produce different regional outcomes. The decision does not decide whether EPA properly rejected the states' pollution plans.
Key Takeaways
- The Court decided where challenges must be filed, not whether EPA's disapprovals were correct.
- State implementation plan disapprovals are locally or regionally applicable actions.
- Regional circuits, not the D.C. Circuit alone, may hear these challenges.
- Justice Alito did not participate.
- The ruling affects forum choice in Clean Air Act litigation.
Decision
6-0, with Justice Alito not participating majority opinion
- Citation
- 605 U.S. 609 (2025)
- Vote
- 6-0, with Justice Alito not participating
- Decision type
- Majority opinion
- Argued
- March 25, 2025
- Decided
- June 18, 2025
- Term
- 2024
- Opinion author
- Clarence Thomas
Justice Thomas wrote the Court's opinion, joined by Justices Sotomayor, Kagan, Kavanaugh, Barrett, and Jackson. Justice Gorsuch concurred in the judgment, joined by Chief Justice Roberts. Justice Alito did not participate.