The head of the Environmental Protection Agency said Monday that he will sign a new rule overriding the Clean Power Plan, an Obama-era effort to limit carbon emissions from coal-fired power plants.

"The war on coal is over," EPA Administrator Scott Pruitt declared in the coal mining state of Kentucky. He said no federal agency "should ever use its authority" to "declare war on any sector of our economy."

For Pruitt, getting rid of the Clean Power Plan will mark the culmination of a long fight he began as the elected attorney general of Oklahoma. Pruitt was among about two dozen attorneys general who sued to stop President Barack Obama's push to limit carbon emissions, stymieing the limits from ever taking effect.

Pruitt talks to a reporter after speaking at Whayne Supply in Hazard, Ky., on Monday. Pruitt said 'no federal agency should ever use its authority to say to you we are going to declare war on any sector of our economy.' (Adam Beam/Associated Press)

Closely tied to the oil and gas industry in his home state, Pruitt rejects the consensus of scientists that man-made emissions from burning fossil fuels are the primary driver of global climate change.

President Donald Trump, who appointed Pruitt and shares his skepticism of established climate science, promised to kill the Clean Power Plan during the 2016 campaign as part of his broader pledge to revive struggling coal mines.

'We think it stops further decline of coal fired plants'

In his order Tuesday, Pruitt is expected to declare that the Obama-era rule exceeded federal law by setting emissions standards that power plants could not reasonably meet.

It was not immediately clear if Pruitt would seek to issue a new rule without congressional approval, which Republicans had criticized the Obama administration for doing. Pruitt's rule wouldn't become final for months, and is then highly likely to face legal challenges filed by left-leaning states and environmental groups.

Pruitt appeared at an event with Senate majority leader Mitch McConnell at Whayne Supply, a Hazard, Kentucky, company that sells coal mining supplies. The store's owners have been forced to lay off about 60 per cent of its workers in recent years.

While cheering the demise of the Clean Power Plan as a way to stop the bleeding, McConnell conceded most of those lost jobs are never coming back.

Sen. Mitch McConnell, seen here greeting people at a coal operation, B&W Resources in Manchester, Ky., in Oct. 2014. (J. Scott Applewhite/Associated Press)

"A lot of damage has been done," said McConnell, a Kentucky Republican. "This doesn't immediately bring everything back, but we think it stops further decline of coal-fired plants in the United States, and that means there will still be some market here."

Obama's plan was designed to cut U.S. carbon dioxide emissions to 32 per cent below 2005 levels by 2030. The rule dictated specific emission targets for states based on power-plant emissions and gave officials broad latitude to decide how to achieve reductions.

The Supreme Court put the plan on hold last year following legal challenges by industry and coal-friendly states.

Even so, the plan helped drive a recent wave of retirements of coal-fired plants, which also are being squeezed by lower costs for natural gas and renewable power, as well as state mandates promoting energy conservation.

'This president has tremendous courage'

The withdrawal of the Clean Power Plan is the latest in a series of moves by Trump and Pruitt to dismantle Obama's legacy on fighting climate change, including the delay or rollback of rules limiting levels of toxic pollution in smokestack emissions and wastewater discharges from coal-burning power plants.

On Thursday, Trump nominated former coal-industry lobbyist Andrew Wheeler to serve as Pruitt's top deputy at EPA — one of several recent political appointees at the agency with direct ties to fossil fuel interests.

The president announced earlier this year that he will pull the United States out of the landmark Paris climate agreement. Nearly 200 countries have committed to combat global warming by reducing carbon dioxide and other greenhouse gases that contribute to global warming.

"This president has tremendous courage," Pruitt said Monday. "He put America first and said to the rest of the world we are going to say no and exit the Paris Accord. That was the right thing to do."

Despite the rhetoric about saving coal, government statistics show that coal mines currently employ only about 52,000 workers nationally — a modest four per cent uptick since Trump became president. Those numbers are dwarfed by the jobs created by building such clean-power infrastructure as wind turbines and solar arrays.

Environmental groups and public health advocates quickly derided Pruitt's decision as short-sighted.

"Trump is not just ignoring the deadly cost of pollution, he's ignoring the clean-energy deployment that is rapidly creating jobs across the country," said Michael Brune, executive director of the Sierra Club.