俄克拉荷马州诉环境保护局案

In 2015, the EPA revised ozone National Ambient Air Quality Standards, requiring states to submit State Implementation Plans (SIPs) under the Clean Air Act's "Good Neighbor" provision. The EPA disapproved 21 states' SIPs in 2023, including those of Oklahoma and Utah, and aggregated them into a single Federal Register rule. Oklahoma and Utah petitioned the Tenth Circuit for review. The EPA moved to transfer the cases to the D.C. Circuit, arguing the omnibus rule was nationally applicable. The Tenth Circuit granted the transfer, finding the rule constituted a single, nationally applicable action. The Supreme Court granted certiorari and reversed. Justice Thomas delivered the 8-0 opinion, joined by Justices Sotomayor, Kagan, Kavanaugh, Barrett, and Jackson. Justice Gorsuch filed a concurring opinion joined by Chief Justice Roberts; Justice Alito took no part.

The Supreme Court held that the EPA's disapprovals of the Oklahoma and Utah SIPs are locally or regionally applicable actions, not nationally applicable. The Court further held that the "nationwide scope or effect" exception did not apply because the disapprovals were based on state-specific, fact-intensive analyses rather than determinations of nationwide scope or effect. The Tenth Circuit's decision was reversed and the cases were remanded for further proceedings consistent with the opinion. Petitioners were awarded $14,233.72 in costs.

The central dispute was whether the EPA's disapprovals of Oklahoma's and Utah's SIPs, published together in a single rule, constituted a "nationally applicable" action reviewable only in the D.C. Circuit, or "locally or regionally applicable" actions reviewable in regional circuits under 42 U.S.C. §7607(b)(1). The EPA argued the omnibus rule was nationally applicable or based on a determination of nationwide scope or effect. The states contended each disapproval was state-specific and thus reviewable in the regional circuit.

The decision reaffirmed the Clean Air Act's cooperative federalism framework by affirming that states can challenge EPA actions in regional circuits rather than being forced to litigate in the D.C. Circuit. It clarified venue rules for environmental litigation, resolving a circuit split and providing guidance on where challenges to EPA actions must be brought. The ruling limits the EPA's ability to aggregate state-specific actions to manipulate venue and signals that agencies cannot avoid regional circuit review by packaging disparate state determinations into a single rule.