Zeldin and lawmakers who spoke on Tuesday praised the original MATS rule, portraying the 2024 update as an overreach by the Biden administration that imposed undue costs on the fossil fuel industry. (“We’re not eliminating MATS,” Zeldin said. “We’re proposing to revise it.”) But the coal industry and red states fought hard against the implementation of the original rule, experts who spoke to WIRED point out.
“They do not want to have increased mercury pollution hung around their neck,” Julie McNamara, an associate director of policy with the Climate & Energy program at the Union of Concerned Scientists, says. “Mercury is a potent neurotoxin that affects the most vulnerable. When coal plants finally installed pollution controls, we had massive mercury pollution reductions and incredible benefits associated with that. I think that’s why they want to try and keep the mantle of protecting public health and interest, while trying to make it seem like these were just radical amendments.”
The rollbacks are part of a larger attack on the EPA’s ability to regulate carbon dioxide as a pollutant, and part of an administration-wide effort to divorce climate science from policy. Earlier this year, Zeldin said that the agency would look to target the endangerment finding, a key determination made by the EPA in 2009 that defined greenhouse gases as dangerous to public health and welfare. That move—outlined in Project 2025—raised public objections even from fossil fuel industry groups like the American Petroleum Institute and the Edison Electric Institute, which represents utility companies.
Killing the endangerment finding would require clearing a much higher legal bar than rolling back power plant regulations. The proposed rules will be open for public comment, with the agency stating a final rule should be issued by the end of the year; experts who spoke with WIRED say that they expect this latest move to be challenged in court. However, they all emphasized the fact that the proposal is above and beyond even what the first Trump administration attempted to do in eliminating climate regulations in its first term.
“This is a very big deal, that the EPA is attempting to sideline itself,” McNamara says. “This is saying, ‘We do not believe that we should regulate carbon emissions from power plants.’ If you can’t justify regulating power plants, then you can’t justify regulating oil and gas emissions.”
Meanwhile, the planet keeps getting hotter. Figures from Mauna Loa Observatory on Hawaii released quietly by NOAA last week show that May had a monthly average of 430.2 parts per million (ppm), the first time in recorded history that seasonal averages of CO2 exceeded 430 ppm, and 3.5 ppm higher than last year’s May average. This reading comes on the heels of similarly-sobering figures the agency downplayed in April showing the largest-ever jump in atmospheric carbon dioxide concentrations between 2023 and 2024.
“Another year, another record,” Ralph Keeling, director of the Scripps CO2 Program, said in a release on the May numbers. “It’s sad.”
