US President Donald Trump has signed an executive order to undo a slew of Obama-era climate change regulations that his administration says is hobbling oil drillers and coal miners.
"My administration is putting an end to the war on coal," Mr Trump said before signing the decree on Tuesday.
"We're going to have clean coal - really clean coal."
The Environmental Protection Agency budget will be cut, plans to slash carbon emissions will be undone and numerous states have been cleared to build coal-fired power stations.
The decree's main target is former President Barack Obama's Clean Power Plan that required states to slash carbon emissions from power plants - a critical element in helping the United States meet its commitment to the Paris climate accord.
The so-called "Energy Independence" order also reverses a ban on coal leasing on federal lands and undoes rules to curb methane emissions from oil and gas production.
"I am taking historic steps to lift restrictions on American energy, to reverse government intrusion, and to cancel job-killing regulations," Mr Trump said.
The wide-ranging order is the boldest yet in Mr Trump's broader push to cut environmental regulation to revive the drilling and mining industries.
Energy analysts and executives have questioned whether the moves will have a big effect on their industries, and environmentalists have called them reckless.
"I cannot tell you how many jobs the executive order is going to create but I can tell you that it provides confidence in this administration's commitment to the coal industry," Kentucky Coal Association president Tyler White said..
Mr Trump signed the order with EPA Administrator Scott Pruitt, Interior Secretary Ryan Zinke, Energy Secretary Rick Perry and Vice President Mike Pence by his side.
Environmental groups hurled scorn on Mr Trump's order, arguing it is dangerous and goes against the broader global trend toward cleaner energy technologies.
"These actions are an assault on American values and they endanger the health, safety and prosperity of every American," said billionaire environmental activist Tom Steyer.
Mr Trump and several members of his administration have doubts about climate change, and Mr Trump promised during his campaign to pull the United States out of the Paris accord, arguing it would hurt US business.
Christiana Figueres, former executive secretary of the United Nations Framework Convention on Climate Change who helped broker the Paris accord, lamented Mr Trump's order.
"Trying to make fossil fuels remain competitive in the face of a booming clean renewable power sector, with the clean air and plentiful jobs it continues to generate, is going against the flow of economics," she said.