Ohio v. Environmental Protection Agency

On June 27, 2024, the U.S. Supreme Court issued a 5–4 decision in Ohio v. Environmental Protection Agency, granting an emergency stay of the EPA's Good Neighbor Plan under the Clean Air Act. The rule required 23 upwind states to reduce nitrogen oxide emissions contributing to ozone pollution in downwind states. Ohio, Indiana, West Virginia, and industry groups challenged the EPA's disapproval of their state implementation plans and the imposition of a federal plan. The Court, in an opinion by Justice Neil Gorsuch, held that the applicants were likely to succeed because the EPA failed to adequately explain whether the federal plan could operate independently if some state disapprovals were later invalidated. The stay blocks enforcement of the rule in the applicant states while litigation continues in the D.C. Circuit. Justices Barrett, Sotomayor, Kagan, and Jackson dissented.

The Supreme Court granted the emergency application for a stay by a 5–4 vote. Justice Neil Gorsuch wrote the majority opinion, and Justice Amy Coney Barrett wrote the dissent joined by Justices Sotomayor, Kagan, and Jackson. The EPA rule remains stayed as to the applicant states while the D.C. Circuit considers the merits.

Whether the Supreme Court should stay the EPA's Good Neighbor Plan pending review; whether the EPA reasonably disapproved state implementation plans and justified its federal plan; and whether the applicant states met the standard for emergency relief.

The ruling temporarily limits the EPA's authority to regulate cross-state air pollution under the Clean Air Act, delaying emission reduction requirements for numerous states. It highlights the Supreme Court's skepticism of broad agency action and may affect downwind states' air quality and the future of cooperative federalism in environmental regulation.