The Trump administration has announced plans to roll back federal limits on mercury and other hazardous air pollutants from power plants, arguing the move will support baseload energy supply as electricity demand rises.
The Environmental Protection Agency (EPA) said easing the standards would reduce costs for utilities operating older coal-fired plants, particularly as power consumption increases due to the expansion of data centres supporting artificial intelligence.
The decision reverses updates made in 2024 under the Biden administration to the Mercury and Air Toxics Standards (MATS), which strengthened rules first introduced in 2012. The 2024 changes aimed to cut allowable mercury emissions from coal plants by 70% and reduce emissions of nickel, arsenic, lead and other toxic metals by two-thirds. The Environmental Defense Fund had estimated the tighter standards would deliver $420 million in health cost savings through 2037.
The Supreme Court had previously declined to suspend the 2024 regulations following a challenge by several Republican-led states and industry groups.
In its final rule published on Friday, the EPA said reverting to the 2012 standards would generate annual savings of between $69 million and $78 million from 2028 to 2037. The agency stated that the 2012 rule already provides “an ample margin of safety to protect public health” and that the 2024 additions imposed costs exceeding their benefits.
Environmental and public health groups criticised the move, warning it would increase exposure to mercury, a neurotoxin linked to impaired brain development in babies, as well as other hazardous pollutants.
Harold Wimmer, president of the American Lung Association, said the 2024 updates would have delivered “$300 million in additional health benefits” and “protected pregnant women, infants and children from harmful exposure and saved thousands of lives each year”.
Research firm Energy Innovation said ageing coal plants continue to face rising maintenance costs, which increased 28% between 2021 and 2024, including at plants affected by the repeal.
Coal-fired plants, which account for less than 20% of US electricity generation according to the Energy Information Administration, are among the largest sources of hazardous air pollutants, including mercury, lead, arsenic and acid gases.
The administration has framed the rollback as part of a broader strategy to meet growing power demand. President Donald Trump previously declared an “energy emergency” to justify keeping certain coal plants online and granted temporary exemptions from MATS requirements to 68 facilities.
