Power plants are the second largest source of carbon dioxide emissions after transportation in the US, and loosening the toxics rules would likely lead to more cases of cancer, brain damage, and birth defects.
Together, the rule changes would cause thousands of premature deaths, according to estimates by the Biden EPA and outside experts.
Trump officials say they are seeking to strike a balance between economic and environmental protections.
“We are proposing to repeal Obama and Biden rules that have been criticised as regulating coal, oil, and gas out of existence,” said EPA Administrator Lee Zeldin.
“Both proposed rules, if finalised, would deliver savings to American families on their electricity bills, and it will ensure they have the electricity that they need.”
The rule changes are part of the Trump Administration’s multi-pronged approach to rolling back emission controls.
Zeldin had previously announced the EPA’s intention to reconsider these and many other environmental rules in March on a day he called “the most consequential day of deregulation in American history”.
As the Washington Post reported in February, Zeldin has been privately urging the White House to strike down the EPA’s 2009 “endangerment finding”, which concluded that greenhouse gas emissions pose a threat to human health and welfare, according to three people briefed on the matter.
That finding underpins most of the federal Government’s actions to confront climate change, including the power plant rules, by allowing greenhouse gases to be regulated under the Clean Air Act.
“By gutting these clean air standards, the EPA is giving a free pass to the nation’s dirtiest power plants and most toxic polluters,” said Representative Sheldon Whitehouse (Democrat, Rhode Island), in a statement reacting to the EPA announcement.
“Pollutants like mercury and greenhouse gases are harmful, a settled scientific fact for decades, and the evidence has only [got] stronger.”
Environmental advocates emphasised the health risks of changing the emissions rules.
“The hazardous air pollutants from coal-fired power plants in particular are hugely harmful to health. Mercury is a neurotoxin. The other emissions host a wide range of health harms for people that breathe emissions from those plants,” said Laura Kate Bender, vice-president of public policy at the American Lung Association.
Business groups have argued that the emissions standards are too strict, driving up costs for coal and gas power plants or forcing them to close down.
“What the Trump Administration is doing is absolutely essential to saving the grid, and that means saving the economy, because without a reliable grid, you can’t have a productive economy,” said Myron Ebell, the former director of the Centre for Energy and Environment at the Competitive Enterprise Institute, a libertarian think-tank.
Ebell said that the mercury and air toxics rules had already led coal plants to close, causing billions of dollars in economic damage that won’t be undone by the EPA’s actions. Rescinding greenhouse gas emissions rules could still benefit plants that burn fossil fuels, he said.
The Government has been swinging from one extreme to another on emissions rules for more than a decade, Ebell added.
“We’ve been playing ping-pong on these rules since the Obama Administration. Obama did them, Trump undid them, Biden did them. Trump’s undoing them.”
The rule changes are certain to face legal challenges from environmental advocates, with the Natural Resources Defence Council’s chief executive Manish Bapna saying in a statement that if EPA goes ahead, “we’ll see them in court”.
