Wisconsin has joined a coalition of 25 states, cities and counties asking a federal appeals court to overturn the EPA's repeal of greenhouse gas limits on coal- and gas-fired power plants — the emission source responsible for roughly one-quarter of U.S. carbon dioxide output.

The coalition filed its petition for review on Oct. 1 in the U.S. Court of Appeals for the District of Columbia Circuit. It seeks to vacate the EPA's repeal of the 2024 Carbon Pollution Standards and restore the emission limits for the power sector.

Wisconsin Attorney General Josh Kaul framed the stakes in direct terms.

"The Trump administration has chosen more wildfire smoke, more extreme weather, more harms to people's health — and, of course, more in profits for the fossil fuel industry," Kaul said. "The EPA should be protecting us from pollution, not clearing the way for it."

A Second Track: Existing Gas Plants

Beyond the court challenge, the coalition has served the EPA with a notice of intent to sue over what it calls the agency's continued failure to regulate greenhouse gas emissions from existing natural gas power plants. That gap matters for grid operations: the notice covers "peaker" plants that run during periods of peak electricity demand, facilities the coalition says are disproportionately sited in low-income communities and communities of color.

The Wisconsin DOJ notes the EPA issued standards for new gas-fired plants more than a decade ago but has never established comparable limits for the existing fleet. That regulatory asymmetry — new units controlled, legacy units uncontrolled — is now the basis for the threatened litigation.

The Legal Argument

In its petition, the coalition argues the EPA unlawfully repealed the 2024 standards without adequately considering alternatives or the health and economic costs of allowing additional emissions. The groups also allege the agency failed to properly calculate the costs of the repeal itself — a claim that goes to the administrative record and the adequacy of the cost-benefit analysis underlying the rollback.

The lawsuit returns the 2024 Carbon Pollution Standards to the D.C. Circuit, the court that has adjudicated the bulk of federal power-sector air regulation disputes over the past two decades.

Wisconsin's Exposure

The Wisconsin DOJ laid out the state-specific case behind its participation. Eliminating the limits, the department said, could contribute to more frequent heat waves, stronger storms, flooding and wildfire smoke, with Wisconsin facing increased heat, extreme storms and severe precipitation under higher-emissions scenarios.

The numbers the department cites are stark. A 2020 University of Wisconsin report found that extreme heat kills more Wisconsin residents than all other weather disasters combined. A 2024 report from the Center for Climate Integrity estimated Wisconsin communities could face more than $16 billion in costs to protect against climate change impacts.

Who Is in the Coalition

The coalition includes attorneys general from 20 states and the District of Columbia, along with the governor of Pennsylvania, the mayors of New York City and Chicago, and the City and County of Denver.

What Comes Next

Two deadlines now define the timeline. The D.C. Circuit will set a briefing schedule on the petition to overturn the repeal of the 2024 standards, and the notice of intent to sue starts the clock on potential litigation over existing gas-plant emissions. How the court weighs the EPA's cost calculations — and whether the agency moves to regulate the existing gas fleet before it is compelled to — will determine whether power-sector carbon limits return, and on what schedule.