A coalition of 21 state Attorneys General* announced the launch of a new court challenge aimed at striking down the Trump administration’s recent repeal of rules designed to significantly reduce greenhouse gas (GHG) emissions from fossil fuel-based power plants.

The coalition, led by New York AG Letitia James warned that the administration’s move will eliminate one of the U.S.’ key climate protection measures, clearing the way for millions of additional tons of greenhouse gas emissions that will worsen extreme heat, deadly storms, flooding, and wildfires.

The new lawsuit follows the repeal by the U.S. Environmental Protection Agency (EPA) in September of a series of Biden-era rules targeting GHG emissions from fossil fuel-based power plants, one of the main sources of the U.S.’ carbon footprint. At the time, the EPA also announced a proposal to rescind the 2015 Greenhouse Gas Findings for Fossil Fuel-Fired Power Plants, effectively making it much more difficult for the agency to reinstitute GHG limiting rules for the fossil fuel-fired power generation sector under future administrations.

The agency’s move had been telegraphed in 2025 by EPA Administrator Lee Zeldin arguing that GHG emissions from power plants “do not contribute significantly to dangerous air pollution” within the scope of the underlying regulation, the Clean Air Act.

In 2015, under the Obama administration, the EPA implemented the Clean Power Plan to regulate limits for CO2 emissions from coal and natural gas power plants, using its authority under the Clean Air Act, which allowed the agency to take actions to address air pollution problems. The move was designed to promote a shift away from coal to cleaner power sources, such as natural gas and renewables.

After the Supreme Court ruled in 2022 that the EPA did not have the authority to devise emissions caps to promote a shift from high-emissions to low-emissions energy generation sources, the Biden administration EPA introduced new standards requiring more CO2 emissions controls to be put in place at fossil fuel-fired power plants, and introducing carbon capture and storage (CCS) requirements for the plants. The EPA’s September move repealed most of the 2024 Biden-era standards, including emissions guidelines for existing fossil fuel-fired plants, and CCS requirements for modified coal plants and new natural gas plants.

According to the New York AG, the states plan to argue that the EPA repealed the power plant pollution limits without properly considering reasonable alternatives or the health and climate costs of allowing more GHG emissions into the atmosphere. The AG’s office added that rescission was “arbitrary and capricious” because EPA did not sufficiently calculate the full cost of repealing the rule.

The coalition filed a petition for review asking the court to strike down the repeal. Additionally, the AGs also filed a notice of intent to sue the EPA for failing to fully regulate pollution form existing gas-fired power plants.

Attorney General James said:

“This administration’s insistence on giving the nation’s biggest polluters a free pass will set our country back decades in the fight against climate change. Dismantling these protections is a betrayal of American families, and the stakes are too high to allow this administration to once again put profits over people.”

*In addition to New York, states joining the court action included Arizona, California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New Mexico, North Carolina, Oregon, Rhode Island, Vermont, Washington, Wisconsin, and the District of Columbia, as well as the Governor of Pennsylvania, the Mayors of New York City and Chicago, and the City and County of Denver.