Colorado sues the EPA for rejecting its clean air plan

Two lawsuits challenge the EPA’s decision

Environmental groups and Colorado’s top lawyer are taking the EPA to court.

The National Parks Conservation Association and Sierra Club filed a petition in the U.S. Court of Appeals for the Tenth Circuit, with the environmental law group Earthjustice representing them.

Colorado Attorney General Phil Weiser filed a separate lawsuit in the same court on the same day, March 4, 2026. Both lawsuits argue the EPA’s full rejection of Colorado’s clean air plan had no legal basis.

Colorado built a plan most sides supported

Colorado sent its Regional Haze State Implementation Plan to the EPA in 2022.

The plan included retirement deadlines for coal-fired power plants that the utilities themselves had volunteered.

It also set emission limits on dozens of other big pollution sources, including the Suncor oil refinery and cement plants across the state. Colorado found the plan would make a real dent in air pollution statewide.

Utilities, industry groups, local governments, and environmental organizations all backed it.

The EPA rejected everything, not just part

The EPA published its full disapproval in the Federal Register on Jan. 26, 2026.

The agency said Colorado didn’t give enough assurance that its plan would follow federal law, including property rights protections in the U.S. Constitution. The issue?

Colorado Springs Utilities pulled its agreement to close the Ray Nixon Power Plant, a coal station south of Fountain, by the end of 2029.

The EPA had first proposed only a partial rejection in July 2025 but expanded it after the utility backed out.

EPA says coal plants shouldn’t close for haze rules

EPA Region 8 Administrator Cyrus Western said the state didn’t need to shut down coal plants to meet federal haze standards.

EPA Administrator Lee Zeldin said reliable energy sources matter and that the agency can meet clean air goals while supporting baseload power.

The EPA also said Colorado “put desire to close power plants over federal law.” The message was clear: the agency wants states to find other ways to cut haze.

Colorado says the rejection ignores the facts

Attorney General Weiser said the EPA based its decision on policy disagreements about coal, not on the law.

He pointed out that utilities chose to retire their coal plants because they decided closure was the cheapest option. Environmental groups argued the rejection overrides choices local utilities made on their own.

The Colorado Department of Public Health and Environment said the state has met its regional haze requirements since 2018, and the EPA’s action didn’t reflect any failure to meet those standards.

The haze rule protects parks nationwide

The federal Regional Haze Rule dates back to 1999, created under the Clean Air Act.

It requires states and federal agencies to improve visibility across 156 protected areas, including national parks, wilderness areas, wildlife refuges, and tribal reservations in 36 states.

The long-term target is to restore natural visibility conditions by 2064. States must develop plans with pollution limits, compliance timelines, and monitoring.

The main culprits behind haze include particulate matter, sulfur dioxide, and nitrogen oxides.

Four Colorado national parks feel the impact

Colorado has four national parks: Rocky Mountain, Great Sand Dunes, Black Canyon of the Gunnison, and Mesa Verde. The state also has dozens of federally designated wilderness areas.

Rocky Mountain National Park ranks among the most visited parks in the country, and haze from coal plants and industrial emissions directly affects it.

Great Sand Dunes and Black Canyon also face threats to their views and air quality from the same pollution sources.

A federal push keeps coal plants running

The EPA’s rejection fits a wider pattern of Trump administration moves to support the coal industry.

On Dec. 30, 2025, the U.S. Department of Energy issued an emergency order forcing Craig Station Unit 1 in Moffat County to stay available through March 30, 2026.

The plant had been set to close Dec. 31, 2025, and had mechanical damage that made it unable to run at the time. Colorado utilities have agreed to close all six remaining coal plants by 2031.

Craig Station sparks a cost fight

The DOE said closing the plant could cut power to homes and businesses, creating a public safety risk.

But the energy consulting firm Grid Strategies estimated Craig Unit 1 could cost about $85 million a year to run at its recent average output.

The plant’s owners, Tri-State Generation and Transmission and Platte River Power Authority, said the order violated their property rights.

Colorado’s governor’s office said the state has no energy emergency and that ratepayers would bear tens of millions in extra costs.

EPA shifts haze policy across the country

In February 2026, the EPA issued new guidance saying it does not support states using power plant closures to meet regional haze rules.

The guidance told states to factor in electric grid reliability when building their plans.

The EPA also proposed to partially reject Hawaii’s haze plan on similar grounds, which suggests the Colorado approach is becoming a national pattern.

An Associated Press analysis found that about 93% of parks and wilderness areas covered by the rule have seen clearer skies since 1999.

Courts and deadlines loom over Colorado

Colorado now has to submit a revised plan, or the EPA will write a federal one for the state. Either version must be done within two years.

Because the EPA threw out the entire plan, emission limits on non-coal sources like the Suncor refinery and cement plants are now in limbo too.

The lawsuits from environmental groups and the attorney general head to the Tenth Circuit. The outcome could shape how other states handle coal closures under the Regional Haze Rule.

Clean air and energy costs hang in the balance

The Regional Haze Rule has helped improve visibility at iconic parks like the Great Smoky Mountains, Grand Canyon, and Rocky Mountain.

The same pollutants that cause haze also contribute to respiratory illness and premature death.

The dispute raises real questions about whether federal clean air protections will hold or get scaled back to favor the energy industry.

Colorado residents could face higher energy bills if aging coal plants keep running past their planned retirement dates.

This article was created with AI assistance and human editing.

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