Kaul sues EPA over greenhouse gas rule repeal

Wisconsin Attorney General Josh Kaul is challenging the U.S. Environmental Protection Agency’s recent decision to declare greenhouse gases no longer harmful to human health.

In mid-February, the agency repealed the endangerment finding, a 2009 rule that named six greenhouse gases, including carbon dioxide and methane, as polluting the air and endangering public health. The rule was used to underpin regulations on greenhouse gas emissions from cars, power plants, and the oil and gas sector.

Wisconsin joins 23 other states; Washington, D.C.; the U.S. Virgin Islands; and several cities and counties across the country in the lawsuit. It was filed March 19 in the U.S. Court of Appeals for the District of Columbia Circuit.

In a news release, Kaul said pretending that climate change is a “hoax” – a description favored by President Donald Trump – won’t make it go away, and that the federal government “should acknowledge what’s actually happening and make decisions based on science.”

EPA Administrator Lee Zeldin said the endangerment finding “severely damaged the American auto industry and massively drove up prices for American consumers” when he announced the repeal last month. Supporters of the repeal contend President Barack Obama didn’t have the authority to issue the finding and bypassed the legislative branch in a case of presidential overreach. Their argument is that the EPA has been issuing unlawful rules since then, based on that faulty finding.

The repeal immediately ended regulation of greenhouse gas emissions from U.S. vehicles and signaled an intent to unwind regulations on other greenhouse gas emitters, like power plants.

More than 99% of scientists agree that humans contribute to climate change through tailpipe fumes and burning fossil fuels for electricity and heat. And last September, a report from the independent National Academies of Sciences, Engineering, and Medicine concluded that evidence for the harm greenhouse gases cause to human health is “beyond scientific dispute.”

When the EPA proposed repealing the endangerment finding in August 2025, Kaul joined comment letters urging the agency to abandon the effort.

The March 19 lawsuit follows a lawsuit from public health and environmental groups, including Clean Wisconsin, that also challenges the repeal.