Supreme Court of the United States · Official docket →
Kentucky, et al. v. Environmental Protection Agency, et al.
Paid petition · United States Court of Appeals for the District of Columbia Circuit, No. 24-1050, 24-1051, 24-1052, 24-1073, 24-1091 · judgment June 26, 2026
(petition-stage, structural)
About 4.8× the 4.1% base rate. The model weights this up for counsel who has won certiorari before, a D.C. Circuit decision below, and a petition filed soon after the judgment below.
Questions presented
The Clean Air Act allows the Environmental Protection Agency (EPA) to revise a national ambient air quality standard (NAAQS) only after a “thorough review” of its air-quality criteria and the current standard. 42 U.S.C. § 7409(d)(1). But in 2024, EPA used a short-circuited reconsideration process—involving an intentionally narrow review of a few limited studies— to revise the air-quality standards for fine particulate matter (PM2.5) to the most restrictive level ever. Although EPA later disavowed any power to revise NAAQS without a thorough review, the D.C. Circuit rejected that concession and approved an expansive view of EPA’s authority anyway. The questions presented are:
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Whether the Clean Air Act gives EPA the authority to revise NAAQS without conducting a thorough review merely because the revision occurs before the normal, five-year review.
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Whether the Clean Air Act bars EPA from considering the costs and feasibility of revising NAAQS when deciding whether to exercise its discretion to undertake a revision before the normal, five-year review.
Counsel of record
For petitioner
Matthew Franklin Kuhn
Office of Attorney General of Kentucky
For respondent
Joshua A. Klein
California Department of Justice
Case
Subject area
Economic Activity (estimated from the questions presented, in the Supreme Court Database’s categories)
Conference history
—
Amicus briefs
9 cert-stage
Related
Vide, 26-298
Proceedings
- Oct 08 2026Motion to extend the time to file a response is granted in part and the time is further extended to and including November 17, 2026.
- Oct 07 2026Motion to extend the time to file a response from November 9, 2026 to December 7, 2026, submitted to The Clerk.
- Oct 07 2026Response of petitioners in opposition to motion for a further extension of time filed.
- Oct 02 2026Brief of Federal Respondents in support filed. VIDED.
- Oct 02 2026Brief amicus curiae of Mountain States Legal Foundation filed. VIDED.
- Oct 02 2026Brief amici curiae of Representative Brett Guthrie, et al. filed. VIDED.
- Oct 02 2026Brief amici curiae of American Fuel & Petrochemical Manufacturers, et al. filed. VIDED.
- Oct 02 2026Brief amici curiae of Western States Trucking Association, et al. filed (as to 26-277).
- Oct 02 2026Brief amici curiae of Competitive Enterprise Institute, et al. filed. VIDED.
- Oct 01 2026Brief amici curiae of Prime Mover Institute, et al. filed. VIDED.
- Oct 01 2026Brief amicus curiae of Job Creators Coalition filed. VIDED.
- Sep 23 2026Brief amicus curiae of Midwest Ozone Group filed. VIDED.
- Sep 22 2026Motion to extend the time to file a response is granted and the time is extended to and including November 9, 2026, for all respondents. See Rule 30.1
- Sep 20 2026Motion to extend the time to file a response from October 2, 2026 to November 7, 2026, submitted to The Clerk.
- Sep 15 2026Brief amici curiae of The Honorable Andrew R. Wheeler, et al. filed. VIDED.
- Aug 28 2026Petition for a writ of certiorari filed. (Response due October 2, 2026)