The Trump administration is moving to roll back the centerpiece of President Barack Obama's efforts to slow global warming, seeking to ease restrictions on greenhouse gas emissions from coal-fired power plants.
"Here's the president's message: The war on coal is over", Pruitt told a gathering in the Kentucky coal-country town of Hazard.
Speaking in Kentucky on Monday, Pruitt said he will sign a proposed rule on Tuesday "to withdraw the so-called clean power plan of the past administration".
"That rule really was about picking winners and losers", he said.
This is the latest example of how the Trump administration is aggressively targeting Obama-era regulations and other efforts to prepare and respond to climate change, from announcing plans to withdraw the U.S. from the Paris climate accord to axing restrictions on building in flood zones. Today's announcement from Pruitt is an expected result of that order.
However, the Clean Power Plan has essentially been on hold since February 2016, when the US Supreme Court halted its implementation until courts could decide whether it was legally valid. "At the same time, we recognize the need for a policy to address greenhouse gas emissions".
CNN obtained a copy of the leaked proposal to repeal the milestone Clean Power Plan, the outcome of President Donald Trump's executive orders calling for the review of the plan and questions the legality of the original rule. Pruitt sued the EPA 13 other times in his capacity as Oklahoma's attorney general for the agency's efforts to regulate mercury, smog and other forms of pollution.
Some experts say weakening the Clean Power Plan will not change the fortunes of the coal industry, which has lost significant share of US power generation to cheap, abundant USA natural gas.
The EPA won't prescribe an immediate replacement to the plan, but will seek public comment on whether to curb climate-warming emissions from coal and natural gas power plants.
Coal-fired power plants are among the largest emitters of carbon.
The plan was supposed to be instrumental in helping the United States reach its goals for the Paris climate agreement, which Obama signed with 195 nations in 2015 and Trump canceled in June.