The Trump administration will stop the Obama-era clean power plan aimed at reducing global warming, EPA Administrator Scott Pruitt said Monday.
Speaking in Kentucky, Mr Pruitt said he will sign a proposed rule on Tuesday "to withdraw the so-called clean power plan of the past administration."
The clean power plan aimed to restrict greenhouse gas emissions from coal-fired power plants. It was a centrepiece of the Obama administration's environmental policies.
President Donald Trump ordered the EPA to rewrite the rule in March.
The Environmental Protection Agency is expected to declare the Obama-era rule exceeded federal law by setting emissions standards that power plants could not reasonably meet.
"The EPA and no federal agency should ever use its authority to say to you we are going to declare war on any sector of our economy," Mr Pruitt said.