WASHINGTON (Reuters) – The Trump administration on Friday said limits on mercury emissions from coal-fired power plants were not necessary as their costs outweighed the benefits, sparking an outcry among environmentalists who say the move favors the coal industry at the expense of public health.

Under the Mercury and Air Toxic Standards, or MATS, enacted under former President Barack Obama, coal-burning power plants have been forced to install expensive equipment to cut output of mercury, which can harm pregnant women and put infants and children at risk of developmental problems.

Since August, the Environmental Protection Agency has been reconsidering the justification for the rule. A coalition of electric utilities has pushed back on the potential loosening of requirements, saying they have already invested in technology to cut emissions of the dangerous pollutant.

A study published this month by Harvard University’s School of Public Health said coal-fired power plants are the top source of mercury in the United States, accounting for nearly half of mercury emissions in 2015. It said the standards have markedly reduced mercury in the environment and improved public health.

In a statement issued on Friday during a partial government shutdown, the EPA said the emission standards of the MATS rule would remain in place. But it proposed withdrawing justification for the requirements after re-examining its cost analysis.

“EPA is proposing that it is not ‘appropriate and necessary’ to regulate HAP (Hazardous Air Pollution) emissions from coal- and oil-fired power plants… because the costs of such regulation grossly outweigh the quantified HAP benefits,” it said.

EPA said its reassessment showed the cost of compliance with MATS was between $7.4 billion to $9.6 billion annually, while the monetized benefits were between $4 million to $6 million. It also said the identification of unquantified benefits was not enough to support the standards.

Among the unquantifiable benefits are reduced healthcare costs, breathing cleaner air and drinking cleaner water, environmentalists say.

“The policy (Acting EPA Administrator) Andrew Wheeler and (President) Donald Trump proposed today means more pregnant women, young children, and the elderly will be exposed to deadly neurotoxins and poisons, just so wealthy coal and oil barons can make a few extra bucks,” Sierra Club Beyond Coal Campaign Director Mary Anne Hitt said in a statement. Wheeler is a former coal industry lobbyist.

“Virtually every coal plant in the U.S. has already met this lifesaving standard, and now Trump is recklessly trying to roll it back,” she said.

‘PLEASE STOP HELPING’

The coal industry had challenged a 2016 conclusion by Obama’s EPA that the rule was justified because savings to U.S. consumers on healthcare costs would exceed compliance costs. The calculations accounted for how pollution-control equipment would reduce emissions of other harmful substances in addition to mercury.

Since taking office in January 2017, Trump has targeted rolling back Obama-era environmental and climate protections to maximize production of domestic fossil fuels, including crude oil. U.S. oil production is the highest in the world, above Saudi Arabia and Russia, after a boom that was triggered more than a decade ago by improved drilling technology.

Trump’s industry allies, including Robert Murray, CEO of private coal mining giant Murray Energy Corp, had complained that the MATS rule contributed to the demise of the coal business by triggering hundreds of coal-fired power plant shutdowns and driving coal demand to its lowest in decades.

U.S. coal-fired power generation has fallen more than 40percent since a peak in 2007, while natural gas-fired generationsoared by about the same amount, according to the EnergyInformation Administration.

Utilities’ demand for U.S. coal is projected to fall furtherthis year, by around 2.5 percent to 648.2 million short tons,the lowest in 35 years, according to the EIA.

Electric utilities and utility groups favoring the rule asked the administration in July to keep it in place. They noted that billions of dollars in investments for anti-pollution equipment have already been made, and costs are being recovered from electricity customers through regulated pricing.

“This is like when your four-year-old kid tries to clean up your kitchen – it actually makes things worse. Please stop helping,” said a utility industry lobbyist based in Washington, who asked not to be named. “The rule itself forced coal plant shutdowns, but they aren’t coming back.”

EPA said it will take comment for the proposal for 60 days and will hold at least one public hearing.