Whether the Clean Air Act preempts state and local governments from regulating manufacturers' post-sale, nationwide updates to vehicle emission systems

QUESTION PRESENTED Title II of the Clean Air Act (“CAA”) grants the U.S. Environmental Protection Agency (“EPA”) broad and exclusive authority to enforce auto manufacturers’ compliance with CAA standards over the entire useful life of their vehicles. To avoid conflicting regulation, Congress directed that “[nlo State or any political subdivision thereof shall adopt or attempt to enforce any standard relating to the control of emissions from new motor vehicles.” 42 U.S.C. § 7548(a). Exercising its authority, EPA reached a multi-billiondollar resolution with petitioners relating to, among other things, post-sale software updates made to their vehicles on a nationwide basis. Certain state and local governments nonetheless brought unprecedented lawsuits seeking substantial additional penalties based on the same updates. The Ohio Supreme Court below—following a decision of the U.S. Court of Appeals for the Ninth Circuit and deepening a direct conflict with final decisions of the Alabama Supreme Court and intermediate appellate courts in Tennessee and Minnesota—held that all 50 states and thousands of local governments may freely regulate manufacturers’ post-sale, nationwide updates to vehicle emission systems. The question presented is whether the CAA preempts state and local governments from regulating manufacturers’ post-sale, nationwide updates to vehicle emission systems. (I)