In a pair of closely watched decisions issued on June 18, 2025, the U.S. Supreme Court answered a critical procedural question under the Clean Air Act (CAA): is the proper venue for judicial review of U.S. Environmental Protection Agency (EPA) actions under the CAA the D.C. Circuit or a regional Circuit Court? Together, these cases provide important guidance for determining where to file actions challenging EPA decisions under the CAA.
In Environmental Protection Agency v. Calumet Shreveport Refining, LLC (Calumet), the Court held that the D.C. Circuit was the proper venue to hear challenges to EPA denials of Renewable Fuel Standard (RFS) program small refinery exemption (SRE) petitions. By contrast, in Oklahoma. v. Environmental Protection Agency (Oklahoma), the Court ruled challenges to EPA's disapproval of State Implementation Plans (SIPs) belonged in the applicable regional Circuit Court (in Oklahoma's case, the Tenth Circuit).
Key Takeaways
Under CAA Section 7607(b)(1), venue for judicial review of EPA actions depends on how the action is classified:
- "Nationally applicable" actions go to the D.C. Circuit;
- "Locally or regionally applicable" actions go to regional Circuit Courts; and
- An exception allows "locally or regionally applicable" actions to be reviewed in the D.C. Circuit if the EPA finds and publishes that the action is "based on a determination of nationwide scope or effect."
The Court's decisions set forth tests courts should apply in determining whether an EPA action is "nationally applicable" or "locally or regionally applicable." The decisions also detail the circumstances in which the exception applies, allowing locally or regionally applicable actions to be reviewed in the D.C. Circuit.
A clear understanding of these cases is critical for any entity considering a challenge to EPA action under the CAA.
Background and Discussion
Calumet: Renewable Fuel Standard (RFS) Small Refinery Exemption Denials
In Calumet, the Supreme Court was asked to determine which Circuit Court can properly hear challenges to EPA's denial of multiple SRE petitions under the CAA's RFS program. The RFS program requires most domestic refineries to blend specified volumes of ethanol and other renewable fuels into the transportation fuels they produce. Small refineries petitioned EPA to grant a total of 105 SREs exemptions, arguing they faced "disproportionate economic hardship."
Following the Supreme Court's decision in HollyFrontier Cheyenne Refining, LLC v. Renewable Fuels Assn., 594 U.S. 382 (2021), EPA denied the SRE petitions in two separate actions (one covering 36 petitions from compliance year 2018, the other covering 69 petitions from compliance years 2016-2021) based on two core principles:
- Hardship must be directly caused by RFS compliance; and
- Small refineries generally pass compliance costs to consumers (the RIN passthrough theory).
Applying these principles uniformly nationwide, EPA issued nationwide denials for 105 petitions, asserting that the decisions were either nationally applicable or locally applicable, but based on nationwide determinations, which triggered D.C. Circuit review.
The Fifth Circuit disagreed with EPA, concluding that the exemption denials were locally applicable actions involving individualized assessments of each refinery's circumstances and, therefore, fell within the jurisdiction of the regional Circuit Courts.
The Supreme Court reversed the Fifth Circuit. The Court first addressed whether an EPA action is "locally or regionally applicable" by evaluating two questions, "what the relevant 'action' is" and "what it means to be 'nationally applicable' as opposed to 'locally or regionally.'" The Court first determined the "action" at issue was each individual denial of an SRE. The Court concluded that because each denial only applies to a single refiner, "which is a particular entity located in a particular place," the denials are "paradigmatically 'locally or regionally applicable' actions." The Court rejected EPA's contention that it could "control the unit of 'action' used to determine venue," observing this would "effectively" allow EPA to control venue under the CAA. The Court concluded the CAA did not authorize "such gamesmanship" or "confer such broad discretion." The Court also rejected EPA's contentions that an action should be deemed "nationally applicable" where it "affects more than one Circuit" or may "have follow-on effects" under the RFS program more broadly.
Evaluating the exception that would allow such actions to be reviewed in the D.C. Circuit, the Court held that, in determining whether the denials have "nationwide scope or effect," "courts should assess EPA's reasoning de novo" and "parse the reasoning offered by EPA in taking an action to decide which determinations primarily drove the action." Here the Court emphasized EPA's uniform application of a consistent framework across all petitions and that both its interpretation of "disproportionate economic hardship" and the RIN passthrough theory were "determinations of nationwide effect that formed the core basis for" its denials.
Oklahoma: State Implement Plan (SIP) Disapprovals
SIPs are a critical element of the CAA, which operates under a cooperative federalism model that generally assigns states the primary role of CAA implementation and enforcement under EPA-approved SIPS. In Oklahoma, the Supreme Court was asked to determine whether EPA's disapproval of Oklahoma and Utah's SIPs were locally or regionally applicable or nationally applicable. The Court concluded that each SIP disapproval constituted a distinct EPA "action" and were "undisputedly locally or regionally applicable actions" because SIP approvals and disapprovals are state-specific decisions governed by §7410 of the CAA. Echoing its determination in Calumet that each EPA SRE denial is "paradigmatically" a "locally or regionally applicable action," that the Court described each decision on an individual SIP as "the prototypical" local action. Accordingly, the Court concluded that each disapproval was local or regionally applicable and, therefore, belonged in a regional Circuit Court under the CAA's venue provision.
The Court rejected EPA's argument that the disapprovals should be treated as a single nationwide action because they were aggregated into an omnibus rule. The Court emphasized that the relevant "action" is defined by the underlying CAA provision, not EPA's packaging. The Court rejected EPA's contention that its use of a "uniform statutory interpretation and common analytical methods" rendered its SIP determinations "nationally applicable," emphasizing this is only relevant to the second step of its analysis and whether its action is "based on a determination of nationwide scope or effect." The determination of whether an action is "nationally applicable" turns on whether "it has binding effect throughout the country."
The Court ruled that the "nationwide scope or effect" exception to regional review did not apply, finding that the disapprovals were primarily based on intensely factual, state-specific analyses, unique to each state's circumstances, rather than a nationwide rationale. Although EPA used certain national-level analytical tools like the 1% contribution threshold as screening mechanisms, these did not primarily drive the decisions. Accordingly, the Court held the SIP disapprovals properly fell within the jurisdiction of the relevant regional Circuit Courts.
Broader Implications
Read together, the cases shed important light on how the CAA's venue selection clause operates. First, the Supreme Court concluded that each small refinery exemption denial and each SIP disapproval are separate, individual actions, that each constitute a "locally or regionally applicable action," suggesting that EPA actions will be considered "nationally applicable" only in narrow circumstances.
Second, because the outcome of the two cases diverged based on how the Court applied the exception for locally or regionally applicable actions to be reviewed in the D.C. Circuit, the cases are especially instructive for the application of this exception.
In Calumet, the Court found that each local exemption denial was based on a uniform national determination affecting all refineries similarly. Contrastingly, in Oklahoma, the Court determined that each SIP disapproval was grounded in individualized, fact-intensive, state-specific analyses unique to each state's plan.
The two decisions also reinforce that the venue for CAA challenges turns not on how EPA organizes or publishes its decisions but on the substantive nature of the underlying action and the scope of EPA's rationale.
Conclusion
The Supreme Court's twin rulings have significant implications for future CAA litigation and clarify the jurisdictional boundaries between regional Circuit Courts and the D.C. Circuit in CAA cases. Accordingly, any entity considering a challenge to an EPA action under the CAA, or considering intervening to support an EPA action, should have a clear understanding of these cases and the underlying venue statute.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
