Amicus Brief: Kentucky v. EPA and Chamber of Commerce v. EPA

The Clean Air Act authorizes the EPA to revise the national ambient air quality standard (NAAQS) only after “a thorough review” of existing air quality criteria and a decision that the revision would “be appropriate.” 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 to the most restrictive level ever. Kentucky and 24 other states challenged the law, and the Chamber of Commerce and other business groups brought a similar challenge. 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. 

Now on petition for Supreme Court review, the petitioners challenge the EPA expedited rule as beyond the agency's authority. The Manhattan Institute has joined the Prime Mover Institute on a brief arguing that the EPA did not base the rule on fully updated air quality criteria and instead chose a selective and partial assessment of recent scientific findings. The fact that the agency chose an expedited process does not remove the statutory requirements. Second, the rule was passed without taking into account whether a standard is attainable. For example, wildfire particles account for 44% of the pollution nationwide, and in some places dust from roads and farming account for most of it. In many parts of the country, it is impossible to comply with the strict standards. The rule is economically damaging and illegal, and the Court should grant review

Ilya Shapiro is a senior fellow and director of Constitutional Studies at the Manhattan Institute. Follow him on Twitter here.

Trevor Burrus is a legal policy fellow at the Manhattan Institute.