Colorado Supreme Court Clears Boulder’s Climate Suit Against Exxon and Suncor Entities
Singleton Schreiber’s Environmental Litigation Practice Continues to Lead on Climate Accountability Nationwide
Denver, CO — In a major legal victory for climate accountability, the Colorado Supreme Court ruled yesterday that Boulder County and the City of Boulder can proceed with their climate accountability suit against Exxon Mobil and Colorado Suncor entities. The case, In re County Commissioners of Boulder County and City of Boulder v. Suncor Energy USA, Inc., et al., brings claims under Colorado common law against defendants Exxon Mobil Corporation, Suncor Energy USA, Inc., Suncor Energy Sales, Inc., and Suncor Energy Inc. seeking to recoup economic losses caused by these defendants’ knowing contribution to alteration of the climate while concealing the dangers of their fossil fuel products.
In a 5–2 decision, the Court rejected the defendants’ arguments that federal law preempts these state law claims. The ruling affirms that Colorado courts have jurisdiction to hear cases seeking damages for local impacts caused by fossil fuel companies.
“Compensating the injured has been the purview of state common law since Colorado’s founding,” said Kevin Hannon, Partner at Singleton Schreiber. “The Colorado Supreme Court simply acknowledged that Colorado common law can apply to hold Exxon and the Suncor entities accountable.”
The Court’s opinion held that federal common law was displaced by the Clean Air Act and that state law claims are not preempted by it. The Court also ruled that Boulder’s lawsuit, which seeks damages rather than emissions limits or an injunction, does not conflict with federal law.
“The Court properly ruled that Colorado law is fully capable and appropriate to address climate harms occurring in Colorado. After over seven years, Boulder County and the City of Boulder can finally have their day in court,” Hannon added.
The Supreme Court’s decision sends the case back to the trial court for further proceedings. The decision does not weigh the merits of the case but confirms that the state law claims are actionable under Colorado law.
In addition to Kevin S. Hannon and Yohania T. Santana of Singleton Schreiber, LLP, the Boulder plaintiffs are represented by EarthRights International, the Law Office of Marco B. Simons, and the Law Offices of David Bookbinder.
“Our firm is built to take on polluters and fight for the health and safety of communities,” said Gerald Singleton, Singleton Schreiber’s Managing Partner. “This decision by the Colorado Supreme Court confirms what we’ve long argued: state courts have a critical role in addressing the damage caused by knowing alteration of the climate and environmental negligence.”
Singleton Schreiber is a client-centered law firm, specializing in mass torts/multi-district litigation, fire litigation, personal injury/wrongful death, civil rights, environmental litigation, insurance bad faith, and sex abuse/trafficking. Over the last decade, the firm has recovered more than $3 billion for clients who have been harmed and sought justice. The firm also has the largest fire litigation practice in the country, having represented over 30,000 victims of wildfire, most notably serving plaintiffs in litigation related to the 2025 Eaton and Hurst Fires, 2025 Moss Landing Battery Plant Fire, 2023 Maui wildfires, the Colorado Marshall wildfire, the Washington Gray wildfire, several California wildfires, and others.
