By Maxine Joselow · The Washington Post (c) 2025
The Senate voted Thursday to overturn an Environmental Protection Agency rule limiting the seven most hazardous air pollutants emitted by chemical plants, oil refineries and other industrial facilities, reversing one of President Joe Biden’s major environmental regulations.
The 52-46 vote delivers a key victory to major companies and trade groups in the fossil fuel and petrochemical sectors that had lobbied against the regulation. It also marks the first time in the Clean Air Act’s 55-year history that Congress has scaled back protections under the landmark environmental law.
Sen. John Curtis (R-Utah) introduced the resolution under the Congressional Review Act, which allows lawmakers to nullify a regulation within 60 days of its enactment with a simple majority vote. The House is expected to pass the same resolution, and President Donald Trump has signaled he will sign it into law.
The EPA rule dictates that once a facility emits any of the seven toxic air pollutants at unsafe levels, it must always maintain strict pollution controls, even if its emissions later drop to safe levels. Inhaling even small amounts of these pollutants – including mercury, alkylated lead and dioxins – can cause cancer, brain damage and other serious health effects.
Environmentalists have strongly supported the regulation, saying it has protected public health in the poor and minority communities that are disproportionately exposed to unhealthy air. But business groups have criticized the rule, saying it has imposed burdensome requirements for companies to monitor, report and reduce their emissions.
According to an analysis by the environmental law firm Earthjustice, the regulation has compelled more than 1,800 facilities nationwide to curb their pollution.
“Repealing this rule would be such a giveaway to corporate polluters,” said Nathan Park, a legislative representative at Earthjustice. “These facilities could increase their toxic pollution without any accountability or oversight.”
Jo Banner, co-director and co-founder of the nonprofit Descendants Project, said scrapping the rule could particularly harm her community of St. John the Baptist Parish in Louisiana. The majority-Black parish lies in a stretch of Louisiana known as “Cancer Alley” because of the many industrial facilities there.
Across the Mississippi River from her neighborhood, Banner can sometimes see pollution billowing from an oil refinery and an aluminum plant. Four of her neighbors either are battling cancer or have recently recovered from the disease. Though it is nearly impossible to prove the cause of these cases, a robust body of scientific evidence has linked air pollution to an increased risk of numerous types of cancer.
“Any time the wind shifts, all of this pollution is coming over to our community,” Banner said. “This impacts our community first and worst.”
Business groups, however, have assailed the rule as burdensome. The National Association of Manufacturers (NAM), a trade group representing 14,000 companies across the country, has led the charge. In a letter sent to Trump one month after the 2024 election, the group included the rule in a list of regulations that it said were “strangling our economy” and should be reversed.
Chris Phalen, the NAM’s vice president for domestic policy, argued in an interview that despite its intent, the rule has disincentivized companies from curbing their pollution.
“We believe the EPA should be rewarding good behavior by encouraging manufacturers to reduce their emissions, and getting rid of the ‘Once In, Always In’ rule will restore the pathway to a win-win outcome: reduced compliance costs on industry for improved environmental outcomes,” Phalen said.
Curtis, the senator, agreed, saying in a statement: “EPA’s current rule eliminates any incentive for major polluters to deploy new technologies to clean up. It effectively told the worst emitters, ‘Don’t worry about coming into compliance – you will never be reclassified.’ That’s backwards.”
The battle over the rule dates to 1995, when a top EPA air official under President Bill Clinton issued a memo establishing a policy known as “Once In, Always In.” The policy dictated that once a facility is classified as a “major source” of 187 air pollutants, it must always meet strict emissions limits, even if it is later reclassified.
During Trump’s first term, the EPA unofficially ended this policy in 2018 and formally revoked it in 2020. The Biden administration never fully reinstated the Clinton-era memo covering all 187 pollutants, opting instead to target the seven most hazardous pollutants in a rule finalized last year.
While Trump’s EPA could have rolled back the Biden-era rule, that regulatory process could have taken years, whereas lawmakers can act immediately under the Congressional Review Act.
Also Thursday, the House passed another Congressional Review Act resolution that would block California from banning sales of new gasoline-powered cars in the state by 2035. It is unclear whether the Senate will follow suit.