Air pollution from coal-fired power plants spiked in 2025, a striking reversal of long-term progress in air quality as the Trump administration boosted coal use.
The emission increases were among the largest in at least a quarter-century, on a percentage basis, as the bulk of about 210 power plants registered increased sulfur dioxide and nitrogen oxide emissions, EPA numbers show.
Releases of sulfur dioxide, a lung-damaging compound key to acid rain formation, soared by more than 18 percent, from about 597,000 tons in 2024 to 705,000 tons in 2025, according to data compiled by POLITICO’s E&E News.
During the same period, the coal-fired power sector’s emissions of smog-forming nitrogen oxides swelled by some 12 percent, from 464,000 to 521,000 tons.
President Donald Trump and congressional Republicans have championed coal power, arguing that it’s needed to ensure the United States’ dominance in artificial intelligence. Trump made reviving the flagging coal industry a national priority, with his administration forcing plants to stay online past their scheduled retirement dates.
Research shows that pollution from the coal-burning plants poses “a serious risk to human health,” said Dan Cohan, an environmental engineering professor at Rice University. While the industry’s total emissions were still well below the levels of even a decade ago, continued increases would threaten one of the Clean Air Act’s signature accomplishments.
“The fact that much more emissions were coming out of them last year was a worrisome sign,” Cohan said.
At EPA, where Administrator Lee Zeldin last year pledged to ensure clean air for all Americans, spokesperson Brigit Hirsch did not address written questions asking how more pollution meshes with that promise or what factors might be behind the increases.
But Hirsch noted in an email steep drops in airborne concentrations of both sulfur dioxide and nitrogen oxides since 1990.
“Cherry-picking one year of data while ignoring the overall downward trend in emission levels is just misleading and meant to distract from the hundreds of environmental wins the Trump EPA has racked up over the past year-plus,” Hirsch said.
But Cohan and other experts view burgeoning electricity demand as a driving force.
Amid a boom in the construction of power-hungry computing centers, even coal-fired units “are starting to see more generation,” said James Staudt, president of Andover Technology Partners, a Massachusetts consulting firm.
‘Total annual emissions increased’
Coal is by far the highest-polluting fossil fuel, and coal-fired generation grew by 13 percent last year, according to recently released U.S. Energy Information Administration data.
At PacifiCorp’s Hunter Power Plant in Utah, for example, NOx emissions skyrocketed 78 percent last year from about 4,500 tons in 2024 to more than 8,000 tons. In an email, PacifiCorp spokesperson David Eskelsen attributed the jump to an increase in “utilization” at the roughly 1,600-megawatt plant.
“Data shows that Hunter generated substantially more electricity in 2025 than in 2024, and total annual emissions increased accordingly,” Eskelsen said, adding that the plant remains in compliance “with all applicable regulatory limits.” He did not reply to a follow-up question asking whether the trend is so far continuing this year.
Under Trump, moreover, EPA is poised to dismantle existing regulations that would further curb coal plant pollution. While two years ago the Supreme Court temporarily blocked implementation of a Biden-era “good neighbor” plan aimed at curbing smog-forming emissions that cross state lines, the agency is now taking first steps toward a permanent rollback.
Also on the administration’s chopping block is a tighter limit adopted during former President Joe Biden’s term on airborne concentrations of the fine particulate matter often dubbed soot. Both SO2 and NOx can help spawn such particles. The Trump administration is now asking the U.S. Court of Appeals for the District of Columbia Circuit to throw out the stricter standard. A ruling is pending.
Coal-burning power plants have historically been a top source of the two pollutants. From 1995 through 2023, however, the sector’s SO2 emissions plunged 96 percent while annual NOx releases fell 90 percent, according to the most recent numbers on an online “progress report.”
Both industry and environmental groups regularly tout those drops as a success story demonstrating that the United States can have cleaner air, economic growth and a dependable electric grid.
“I think that the long-term trend has shown that we’ve been able to cut pollution without hurting reliability,” said Amanda Levin, director of policy analysis at the Natural Resources Defense Council.
In her own recent dissection of the data from EPA’s Clean Air Markets program, Levin found that the overall growth in SO2 emissions last year was disproportionately higher among 71 plants granted presidential exemptions last year from other regulations issued during Biden’s term that strengthened power sector limits on mercury and other toxic pollutants.
Those regulations, formally known as the Mercury and Air Toxics Standards and repealed last month, did not directly target releases of SO2 or NOx. Levin, however, saw the trend as evidence that the plants seeking exemptions were especially willing to take advantage of a “more permissive” regulatory environment.
In her email, Hirsch wrote that the standards had “little or nothing to do” with NOx or SO2 emissions and accused Levin’s group of “a desperate attempt to drum up donations.”
Before Trump’s second term, EPA had routinely updated the emissions data for individual power plants in an online spreadsheet roughly every three months. The agency has since ended that tradition without explanation. For this story, E&E News extracted the plant numbers from the Clean Air Markets clearinghouse with the help of a former EPA staffer who was granted anonymity for privacy reasons.
For some individual plants, pollution spikes last year were well above the percentage increases for the coal-fired power sector as a whole, the numbers indicate. At NRG Energy’s Limestone operation in East Texas, for example, SO2 releases almost quadrupled from about 4,500 tons to some 17,000 tons.
In an email, NRG spokesperson Erik Linden described the data as inaccurate, saying that an emissions monitoring system breakdown and EPA data substitution rules led to the plant “reporting more emissions than [were] actually emitted.”
At Ameren’s Labadie Energy Center in St. Louis, SO2 emissions climbed 17 percent last year, slightly below the industrywide total. Even so, the 38,300 tons in releases were the highest of any coal-fired power facility in the United States. The Labadie plant was also among the coal-fired power sector’s top 10 sources of nitrogen oxides, with total emissions rising 15 percent to almost 7,700 tons.
In a statement, Craig Giesmann, director of environmental services for Ameren Missouri, did not answer written questions about the factors behind the added pollution last year, but said the Labadie operation continues to meet emissions requirements that “are fully protective of human health.”
The plant is also “a critical asset” to St. Louis and the state of Missouri, Giesmann said. “Keeping the lights on is a job we take seriously, and so is our responsibility to the environment.”
After reviewing the data, Peter Goode, an environmental engineer with the interdisciplinary environmental clinic at Washington University in St. Louis, said in an email that he believed the 2025 SO2 emissions increase stemmed from added plant operations.
For both 2024 and 2025, he added, the numbers “are still incredibly high.”
Reach this reporter on Signal at SeanReilly.70.
