County Commissioners of Boulder County v. Suncor Energy USA, Inc.

A 5-2 majority of the Colorado Supreme Court concluded that federal law did not preempt common law tort claims brought by the County Commissioners of Boulder County and the City of Boulder (together, Boulder) under Colorado law against four fossil fuel companies seeking damages for the companies’ alleged role in exacerbating climate change and causing harm to Boulder and its residents. Boulder asserted claims of public and private nuisance, trespass, unjust enrichment, and civil conspiracy. The court concluded that federal common law did not preempt Boulder’s state law common law claims because the Clean Air Act had displaced federal common law concerning air pollution. Instead, the court considered whether the Clean Air Act preempted the claims and determined that no form of preemption—express, field, or conflict—applied. The court also found that Boulder’s claims did not involve “uniquely federal areas of regulation” and that litigating the claims “would not upset any balance set by Congress because Boulder’s claims do not seek to impose liability for activities” regulated by the Clean Air Act. The court also disagreed with the fossil fuel companies’ contention that Boulder asserted what formerly would have been federal common law claims. The court said Boulder was not bringing an action against a “pollution emitter to abate pollution” but instead was seeking “damages from upstream producers for harms stemming from the production and sale of fossil fuels.” The court also found that the defendants did not support the proposition that because federal common law formerly existed, the Constitution’s structure precluded application of state law even though the federal common law no longer existed. The court also rejected the contention that state law claims previously preempted by federal common law could only proceed if authorized by federal statute. In addition, the court rejected arguments that Boulder’s claims were essentially attempts to regulate greenhouse gas emissions and therefore preempted by the Clean Air Act; instead, the court found that the common law claims “seek compensation for allegedly tortious conduct” not addressed by the Clean Air Act. The court also was not persuaded that the federal foreign affairs power preempted Boulder’s claims. The Supreme Court discharged the order to show cause and remanded to the district court for further proceedings, noting that it was not expressing any opinion on the “ultimate viability” of the claims. Two justices dissented. They would have considered whether the Clean Air Act affirmatively authorized “the interstate aspect of Boulder’s claims” and would have concluded that it did not. They also would have concluded that the federal government’s “primacy in foreign affairs” precluded the international aspect of Boulder’s claims.

The Colorado Supreme Court scheduled oral argument for February 11, 2025 in the climate change case brought by the City of Boulder and Boulder County against Exxon Mobil Corporation, Suncor Energy USA, Inc., and related companies. The Supreme Court agreed in July 2024 to consider whether a district court erred when it allowed the City and County to proceed with claims under state law.

On July 29, the Colorado Supreme Court ordered the Board, the City, and the district court to address why the Supreme Court should not grant the issue raised in the defendants' petition regarding “[w]hether the district court erroneously concluded that respondents’ claims could proceed under state law.” The Supreme Court denied the petition with respect to the issue of “[w]hether a Colorado tribunal may exercise personal jurisdiction over an out-of-state defendant for its alleged contributions to interstate and international GHG emissions that are not traceable to conduct in Colorado.” The responses are due by August 26, and Exxon has 14 days from receipt of the answer to reply.

On July 16, 2024, ExxonMobil Corporation (Exxon) filed a petition for order to show cause in the Colorado Supreme Court in which Exxon asked the court to reverse Colorado District Court rulings allowing the Board of County Commissioners of Boulder County and the City of Boulder to proceed with their lawsuit seeking to hold the companies liable for climate change harms. Exxon argued that no adequate remedy was available absent review by the Supreme Court and that the district court’s rulings raised issues of significant public importance that the Supreme Court had not yet considered.