It usually takes at least three to start a trend, but two recent appellate-level decisions suggest a new air pollution enforcement trend is in the making: Environmental plaintiffs may be able to avoid Clean Air Act (CAA) preemption by bringing state common-law tort claims against an intrastate emitting source. The plaintiffs in both Bell v. Cheswick and Freeman v. Grain Processing Corp. successfully convinced the U.S. Court of Appeals for the Third Circuit and the Iowa Supreme Court, respectively, that the CAA did not preempt their tort claims based on state common law. The result—as well as the U.S. Supreme Court’s denial of certiorari in both cases—surprised observers because the Supreme Court has held previously that the CAA preempts similar tort claims based on federal common law. It is too early to ascertain the full impact of these decisions, however, and recent rulings in other class action cases suggests that courts may be hesitant to certify classes of plaintiffs with injuries that vary significantly from one plaintiff to another. Nevertheless, by resorting to torts that date back over 400 years, plaintiffs may open the door to litigation against facilities that are otherwise meeting their regulatory obligations.