The Supreme Court, in American Electric Power Co., Inc. v. Connecticut, 131 S. Ct. 2527 (2011), held that the Clean Air Act (CAA) preempts federal common law claims relating to a CAA permittee’s air emissions. American Electric expressly left open the question of whether the CAA also preempts state common law claims. District courts relied on the Court’s reasoning in American Electric to hold that the CAA also preempts allstate common law claims. Recently, however, the Third Circuit, in Bell v. Cheswick Generating Station, 734 F.3d 188 (3d Cir. 2013), reversed one of these district court decisions and held that the CAA does not “shield” permittees from state common law claims.