If finalized, the repeal would end current limits on greenhouse gas pollution from vehicle tailpipes, power plants, smokestacks and other sources, and hamper future U.S. efforts to combat global warming.

Environmental Protection Agency Administrator Lee Zeldin announced the agency's plan to rescind the "endangerment finding" at an event at a car dealership in Indiana, alongside Energy Secretary Chris Wright, and called it the largest deregulatory action in U.S. history.

The proposal, which needs to undergo a public comment period, would cut $54 billion in costs annually through the repeal of all greenhouse gas standards, including the vehicle tailpipe standard, he said.

Under President Joe Biden, the EPA said the tailpipe rules through 2032 would avoid more than 7 billion tons of carbon emissions as it prodded automakers to build more EVs and provide nearly $100 billion of annual net benefits to society including $62 billion in reduced fuel costs, and maintenance and repair costs for drivers.

Environmental groups blasted the move, saying it spells the end of the road for U.S. action against climate change, even as the impacts of global warming become more severe.

"With today’s announcement, the EPA is telling us in no uncertain terms that U.S. efforts to address climate change are over. For the industries that contribute most to climate change, the message is 'pollute more.' For everyone feeling the pain of climate disasters, the message is 'you’re on our own,'" said Abigail Dillen, president of Earthjustice.

The move is expected to trigger legal challenges, according to several environmental groups, states and lawyers.

Zeldin said a 2024 Supreme Court decision that reduced the power of federal agencies to interpret the laws they administer, known as the Chevron deference, means that the EPA does not have the ability to regulate greenhouse gases.

"We do not have that power on our own to decide as an agency that we are going to combat global climate change because we give ourselves that power," Zeldin said.

He added that if Congress decides it wants to amend the federal Clean Air Act to explicitly state the U.S. should regulate carbon dioxide, methane and other planet-warming gases, the EPA would follow its lead.

SHAKING THE FOUNDATION

The endangerment finding's roots date back to 2009, when the EPA under former Democratic President Barack Obama issued a finding that emissions from new motor vehicles contribute to pollution and endanger public health and welfare.

That assessment followed a 2007 U.S. Supreme Court decision in its landmark Massachusetts v. EPA case that said the EPA has the authority under the Clean Air Act to regulate greenhouse gas emissions and required the agency to make a scientific finding on whether those emissions endanger public health.

The endangerment finding was upheld in several legal challenges and underpinned subsequent greenhouse gas regulations, ranging from tailpipe standards for vehicles, carbon dioxide standards for aircraft, and methane standards for oil and gas operations.

Zeldin and Wright challenged the global scientific consensus on climate change that global warming and its impacts have since been unfolding faster than expected and that policymakers need to step up action to curb global greenhouse gas emissions.

They also contradict the advisory opinion issued last week by the International Court of Justice, which said failure by governments to reduce emissions could be an internationally wrongful act, and found that treaties such as the 2015 Paris Agreement on climate change should be considered legally binding.

The administration has already dismissed all authors of the U.S. National Climate Assessment, which detailed climate change impacts across the country.

"Now the public is open to engage in a thoughtful dialogue about what is climate change? It is a real physical phenomenon. It's worthy of study. It's worthy of even some action, but what we have done instead is nothing related to the actual science of climate change or pragmatic ways to make progress," Wright said.

Zeldin said on a podcast earlier Tuesday that the endangerment finding never acknowledged "any benefit or need for carbon dioxide."

Industry reaction was limited on Tuesday, with some trade groups weighing in and some companies remaining quiet.

American Trucking Associations welcomed the announcement, saying that Biden-era vehicle emissions standards "put the trucking industry on a path to economic ruin and would have crippled our supply chain," said its president, Chris Spear.

Ford (F.N) said in a statement that Biden-created tailpipe standards did "not align with the market," and America needs "a single, stable standard to foster business planning."

"The standard should align with science and customer choice, reduce carbon emissions by getting more stringent over time, and grow American manufacturing," Ford said.

Other automakers Toyota (7203.T), GM (GM.N), Stellantis (STLAM.MI) declined to comment.

Marty Durbin, president of the Global Energy Institute at the U.S. Chamber of Commerce, said it welcomed the administration's focus on affordable energy but said it is still weighing the proposal.

"While we did not call for this proposal, we are reviewing it and will consult with members so we can provide constructive feedback to the agency,” he said.

California Air Resources Board chair Liane Randolph said the EPA move chooses "polluter fantasyland over proven science. Meanwhile, back on Earth, the planet continues to suffer the consequences of unchecked carbon pollution."