After axing a federal doctrine to regulate greenhouse gas emissions earlier this month, the Trump administration rolled back additional air quality standards Friday — this time for limiting mercury and other deadly toxins from coal smokestack emissions.
U.S. Environmental Protection Agency Administrator Lee Zeldin announced the agency’s repeal of Biden-era amendments that increased mercury and air toxics standards. The repeal applies to mercury and other heavy metals from coal and oil-fueled power plants. Burning coal accounts for the majority of mercury emissions in the nation.
The revised standards essentially revert back to a 2012 update that is “fully protective of human health risks,” according to EPA, and will forgo an estimated $670 million cost to power plant operators — “Savings American families will see in the form of lower everyday living costs.”
“The Biden-Harris administration’s anti-coal regulations sought to regulate out of existence this vital sector of our energy economy,” Zeldin said in a prepared statement. “If implemented, these actions would have destroyed reliable American energy.”
Mercury is a potent neurotoxin that attacks the central nervous system, damages organs and is especially toxic to children, according to the EPA. When mercury is spewed from smokestacks, it settles in lakes, streams and oceans. It builds up in fish and shellfish that, when consumed by humans, presents a health risk.
“Weakening these clean air rules for the benefit of coal plants — it doesn’t make us more energy independent. I think it just makes people sick,” Earthjustice Senior Attorney Nicholas Morales told WyoFile.
“This move puts the American people at higher risk of cancer, asthma attacks, brain damage and other life-changing health problems,” the Center for American Progress said in a prepared statement.
While EPA touted cost savings to coal-burning utilities, it didn’t estimate the potential impact for human health. Last month, the agency ended the decades-long practice of calculating human health implications related to its air pollution actions.
“The Trump EPA knows that we can grow the economy, enhance baseload power and protect human health and the environment all at the same time,” Zeldin said. “It is not a binary choice and never should have been.”
What it means for Wyoming
What the rollback means for Wyoming — the nation’s largest supplier of coal burned to generate electricity — is unclear. Power plants that burn lignite-grade coal — not subbituminous Powder River Basin coal — account for most of the mercury emissions from coal smokestacks, according to the EPA. Compared to other U.S. coals, Wyoming coal is less saturated with mercury and other heavy metals.
In fact, federal clean air standards are largely responsible for Wyoming’s mammoth mining industry, beginning with the Clean Air Act of 1970. Electric utilities had invested in a large fleet of coal-burning power plants, and with the Clean Air Act they needed to cut ash, sulfur oxide and nitrogen oxide emissions. They turned to the Powder River Basin — coal there has less sulfur — in the 1970s, and Wyoming mines boomed.
Amid stagnant coal sales in the 1990s, environmental policies once again came to the rescue. An amendment to the Clean Air Act to address “acid rain” tilted electric utilities’ favor even further toward low-sulfur Powder River Basin coal.
How much of an advantage Wyoming coal earns for its lower mercury content is hard to say.
“I suppose we could have had a slight advantage,” Wyoming Mining Association Executive Director Travis Deti said. “But I would say other factors such as price and low-sulfur content also play to our advantage.
“The 2024 MATS rule, combined with other [Biden-era] EPA rules, were specifically designed to accelerate coal plant retirements,” Deti continued. “So we’re pleased with its repeal. It will help ensure that coal generation can continue supporting the nation’s electric grid, and this is obviously a good thing for Wyoming coal.”
Most coal plants were in compliance
A savings of $670 million, in the realm of power-plant emission controls, might not be considered a make-or-break prospect for the nationwide coal-power fleet, according to some.
The Biden-era’s more stringent standards of 2024 were intended to motivate a few laggard mercury polluters to either clean up or shut down, according to Earthjustice’s Morales. He noted that most coal plants had already been upgraded to meet the 2012 standards. In fact, the adoption of emission controls helped bring down the cost of doing so, according to EPA.
Still, there remained some stragglers, Morales noted, like Colstrip Generating Station in Montana and the Oak Grove plant in Texas. Those were also among dozens of coal plants that, last year, received an exemption to meet the new 2024 mercury standards until the Trump administration could roll them back.
“So this isn’t about keeping the lights on,” Morales said. “It’s really about giving a handout to polluters at the expense of public health.”
The EPA’s 2025 exemption list also included Powder River Basin coal-burning power plants Laramie River Station outside Wheatland and Dry Fork Station north of Gillette.
Even if the Biden mercury standards were narrowly focused to motivate a slice of the nation’s coal fleet, rolling them back still presents a hazard, according to Morales. Though many electric utilities attempt to plan years ahead to meet trending standards rather than zigzag to the whipsaw of federal policy, some will eagerly take advantage of the mercury regulation rollback, he said.
“When you take away the requirements to control pollution, coal plant [operators] are going to do what makes the most sense economically, and in many cases that may be for them saving a few dollars by not improving their emission control equipment. You know, more sickness and higher medical bills for people who live near coal plants.”