On June 18, the U.S. Supreme Court issued two decisions that clarify a deceptively simple question under the Clean Air Act: Where should lawsuits challenging EPA actions be filed?
The rulings – EPA v. Calumet Shreveport Refining LLC and Oklahoma et al. v. EPA – do not change the substance of environmental law, but they do shape how and where that law gets litigated. And that matters.
At the heart of both cases is a venue provision in the Clean Air Act, which says that challenges to EPA actions must be filed in the D.C. Circuit if the action is “nationally applicable” or based on a “determination of nationwide scope or effect.” Otherwise, the case belongs in the regional circuit where the action applies. That distinction – between national and local – was tested in two very different regulatory contexts: biofuel blending waivers and state ozone control plans.
In Calumet, a group of small refiners challenged the EPA’s denial of exemptions from the Renewable Fuel Standard, which requires blending ethanol and other biofuels into transportation fuels. The refiners filed in the Fifth Circuit, arguing that the denials were specific to their individual facilities and thus locally applicable. The EPA disagreed, saying its decisions were based on broader legal and economic interpretations that affect the entire industry and should therefore be reviewed in the D.C. Circuit.
The Supreme Court, in a 7–2 decision, sided with the EPA. Writing for the majority, Justice Clarence Thomas acknowledged that the denials were directed at specific refineries. But he emphasized that the agency’s reasoning – particularly its interpretation of “disproportionate economic hardship” and its view that compliance costs are typically passed on to consumers – had nationwide implications. That was enough to trigger the Clean Air Act’s exception and send the case to the D.C. Circuit.
Justice Gorsuch, joined by Chief Justice Roberts, dissented. He argued that the statute calls for a case-by-case review of hardship, not a sweeping policy judgment. In his view, the majority’s approach risks turning straightforward venue questions into drawn-out legal battles. His concern was that this new test could make it harder – and more expensive – for regulated parties to know where to bring their claims.
The second case, Oklahoma v. EPA, involved the agency’s rejection of state implementation plans (SIPs) for ozone control submitted by Utah and Oklahoma. The EPA had bundled these rejections into a single omnibus rule affecting 21 states. But the court unanimously held that each state’s plan was a separate action based on localized facts, and therefore should be reviewed in the appropriate regional circuit – in this case, the Tenth Circuit.
Again writing for the court, Justice Thomas rejected the EPA’s argument that the omnibus nature of the rule made it nationally applicable. He pointed out that the agency itself had acknowledged the state-specific nature of its decisions. Because the disapprovals weren’t based on a nationwide determination, the D.C. Circuit wasn’t the right venue.
These decisions do not change the Clean Air Act’s venue rules, but they do clarify how courts should apply them. The key takeaway is that it is not just the geographic reach of an EPA action that matters – it is the reasoning behind it. If the agency relies on broad statutory interpretations or economic theories that apply across the board, the federal D.C. Circuit is likely the right forum. But if the action is grounded in state-specific facts, regional courts remain the proper venue.
For environmental lawyers, this matters more than it might seem. Venue can influence everything from the pace of litigation to the applicable precedent. It can also affect who gets to participate in the case and how accessible the process is for local stakeholders. These rulings offer a clearer framework for evaluating where to file or defend Clean Air Act challenges – and a reminder that procedural rules can shape the outcome just as much as the merits.
These Supreme Court holdings also reflect a broader tension in environmental law: the balance between national consistency and local flexibility. As the EPA continues to regulate complex issues like air quality, climate policy, and fuel standards, that tension is not going away. But with these recent decisions, the rules of the road are a little clearer.