Colorado District Court Latest to Dismiss Industry Lawsuit Against Building Updates

A Colorado District Court has dismissed a corporate-backed lawsuit against Denver ordinances aimed at reducing air pollution from buildings and reducing energy bills for owners and tenants. The court agreed with arguments made by the City of Denver and Sierra Club that federal law does not preempt the codes, and granted the parties’ request to dismiss the case.

“Denver residents support action against severe pollution and this decision upholds a community’s local right to cut harmful air pollution,” said Dylan Plummer, deputy director of the Sierra Club’s Clean Heat Campaign. “Everyone deserves to breathe clean air, and Denver’s codes will help businesses and residents save money and improve public health.”

Denver’s building codes were written with input from industry groups. At times this summer, the city saw the worst air quality in the world as severe air pollution mixed with wildfire smoke.

“This decision correctly recognizes that Denver and other local governments have authority to regulate the use of polluting gas appliances in homes and buildings,” said Emma Hardy, associate attorney with Earthjustice’s Rocky Mountain Office. “The court in Colorado joined numerous other courts across the country that have recently recognized that federal law does not prevent states and local governments from adopting laws that encourage building electrification and limit the use of certain gas appliances for space and water heating.”

The District Court’s decision dismissed corporate-backed claims that the federal Energy Policy and Conservation Act (EPCA) pre-empts local government policies to reduce pollution from sources including certain gas-fired appliances. Since 2024, federal courts across the U.S. have upheld local and state authority to regulate pollution from buildings, including in New York, Washington, D.C., Maryland, Illinois, and California.

“These baseless lawsuits are a fossil fuel industry-funded strategy designed to fight regulation, and delay common sense policies to modernize homes and buildings and reduce energy costs,” continued Plummer.

Denver’s updated energy code passed in 2023 aims to modernize buildings to reduce pollution and be more climate resilient. As the city faces increasing wildfire pollution and extreme heat, the code ensures homes and businesses are able to withstand modern challenges, while reducing energy use and bills. By supporting a transition from fossil fuel heating and building equipment to modern electric systems like heat pumps, the codes help building owners reduce pollution and avoid the volatile price swings of fossil fuels.

The plaintiffs included corporate landlord associations, the National Propane Gas Association, and Colorado Restaurant Association. Sierra Club intervened in 2024, with legal representation from both Earthjustice and Sierra Club’s in-house attorneys.