The Supreme Court has held in Am. Elec. Power Co., Inc. v. Connecticut that the CAA preempts tort claims under federal common law and in International Paper Co. v. Ouellette that the Clean Water Act does not preempt state common law claims under the law of the state that is the source of the alleged pollution. However, it explicitly left open the question of whether the Clean Air Act preempts tort claims under state common law. See Am. Elec. Power, 131 S. Ct. at 2540 (“None of the parties have briefed preemption or otherwise addressed the availability of a claim under state nuisance law. We therefore leave the matter open for consideration on remand.”).
There is already an arguable circuit split on this question, and the Sixth Circuit will soon be forced to stake out its own position. In Bell v. Cheswick Generating Station, the Third Circuit held that the CAA does not preempt claims under the common law of a source state. In North Carolina v. Tennessee Valley Authority, the Fourth Circuit wrote that the Supreme Court in Ouellete “created the strongest cautionary presumption against” state law nuisance actions where state standards differed from federal standards, a dictum that did not distinguish between source and affected states (although the case involved only affected-state claims) and thereby suggested a broader view of CAA preemption. The Sixth Circuit has previously held that the Clean Air Act does not preempt statutory state law claims, but has not addressed common law state claims such as nuisance.
In Merrick v. Diageo Am. Supply, Inc., the Western District of Kentucky recently held that the CAA does not preempt common law tort claims under the law of the source state, consistent with some other decisions by district courts in the Sixth Circuit. See Little v. Louisville Gas & Elec. Co., 2014 U.S. Dist. LEXIS 96947 (W.D. Ky. July 16, 2014); Technical Rubber Co. v. Buckeye Egg Farm, L.P., 2000 U.S. Dist. LEXIS 8602 (S.D. Ohio June 16, 2000). Last month, the Merrick court certified this issue for an interlocutory appeal to the Sixth Circuit.
The Supreme Court denied certiorari in Bell last month, but a Sixth Circuit decision in Merrick might be the final straw in persuading the Supreme Court to address this issue.