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

2025 CO 21. No. 24SA206. Federal Preemption—Clean Air Act.

May 12, 2025

In this original proceeding under C.A.R. 21, the supreme court considered whether the district court erred in concluding that the state law tort claims brought by respondents against petitioners are not preempted under federal law and may therefore proceed.

The court concluded that respondents’ claims are not preempted by federal law and, therefore, the district court did not err in declining to dismiss them. Accordingly, the court discharged its order to show cause and remanded the case to the district court for further proceedings consistent with this opinion.