WASHINGTON — The Environmental Protection Agency’s administrator, Scott Pruitt, told coal miners in Kentucky on Monday that he will move to repeal a rule limiting greenhouse-gas emissions from existing power plants, assuring them, ‘‘The war against coal is over.’’
Speaking in Hazard, Ky., with Senate majority leader Mitch McConnell of Kentucky, Pruitt said the EPA will publish a new proposed rule Tuesday.
‘‘I'll be a signing a proposed rule to withdraw the so-called Clean Power Plan of the past administration, and thus begin the effort to withdraw that rule,’’ Pruitt said.
Attorneys general in several states — Massachusetts, California, and New York among them — vowed to challenge the decision.
A draft of the proposal contends the agency overstepped its authority in seeking to force utilities to reduce carbon emissions outside their actual facilities to meet federal emissions targets.
It does not offer a replacement plan for regulating emissions of carbon dioxide, which the Supreme Court has ruled the EPA is obligated to do. Rather, the agency said it plans to seek public input on how best to cut emissions from natural-gas and coal-fired power plants.
Monday’s announcement brought promises of even more legal fights.
A 2009 EPA determination that carbon dioxide constitutes a pollutant under the Clean Air Act is still in place, so the agency will have to justify how it is complying with that finding as it rolls back the regulation.
‘‘Along with our partners, Massachusetts fought for years to put this rule in place, and we will be suing to protect the Clean Power Plan from the climate change deniers in this administration who are trying to move us backward,’’ Massachusetts Attorney General Maura Healey said in a statement.
New York Attorney General Eric Schneiderman also promised to sue, the Associated Press reported.
‘‘The Trump Administration’s persistent and indefensible denial of climate change — and their continued assault on actions essential to stemming its increasing devastation — is reprehensible, and I will use every available legal tool to fight their dangerous agenda,’’ said Schneiderman, a Democrat.
EPA spokeswoman Liz Bowman said Pruitt chose to speak in Kentucky because coal workers have a direct economic stake in policies aimed at curbing emissions from coal burning.
Reaction to the announcement was divided sharply along ideological lines, with environmental and public health advocates decrying it and industry groups welcoming the move.
‘‘With this news, Donald Trump and Scott Pruitt will go down in infamy for launching one of the most egregious attacks ever on public health, our climate, and the safety of every community in the United States,’’ said Michael Brune, Sierra Club executive director. ‘‘He’s proposing to throw out a plan that would prevent thousands of premature deaths and tens of thousands of childhood asthma attacks every year.’’
But the National Rural Electric Cooperative Association’s chief executive, Jim Matheson, said rescinding the regulation would provide his members with the flexibility to use their plants to provide ‘‘reliable, affordable power.’’
Sixty-two percent of coop-owned generation is coal-fired, according to the association, while natural gas accounts for 26 percent, nuclear power 10 percent, and renewables 2 percent.
‘‘That’s what we’re really looking for, is flexibility so they can meet their individual consumers’ needs,’’ Matheson said.
Even some critics of the rule said Monday that they were open to a more limited regulation aimed at addressing carbon emissions.
Ross Eisenberg, vice president at the National Association of Manufacturers, said his group ‘‘agrees with the EPA’s conclusion that this regulation was broader than what the law allows, which is why we joined 28 states in challenging it in federal court.’’
‘‘At the same time, we recognize the need for a policy to address greenhouse gas emissions,’’ Eisenberg added, saying the group ‘‘supports a greenhouse gas policy going forward that is narrowly tailored and consistent with the Clean Air Act.’’
The Clean Power Plan, which aimed to decrease carbon pollution by about one-third by 2030, compared with 2005 levels, has long been subject to legal fights — and that much is unlikely to change.
During his time as Oklahoma’s attorney general, Pruitt joined others in suing the Obama administration, arguing it did not have legal authority to force states to form detailed plans to reduce CO2 emissions from such sources as coal-fired power plants.
Pruitt sided with industry officials who insisted the EPA’s regulations would unfairly force power-plant owners to shut down or essentially subsidize competing clean-energy industries.
Environmental groups and other supporters argued on the side of the Obama White House, saying the administration had standing under the Clean Air Act to put in place the effort, which they called a much-needed measure to help nudge the nation toward cleaner sources of energy and improve public health.
Early last year, the Supreme Court blocked the regulation’s implementation after 27 states and a host of other opponents challenged it. Its 5-to-4 decision, which did not address the merits of the lawsuit, came days before the death of Justice Antonin Scalia.
Meanwhile, a 10-judge panel of the US Court of Appeals for the District of Columbia Circuit in September 2016 heard oral arguments but did not rule before the Trump administration took office and requested time to reconsider the rule.
The EPA’s latest proposal comes months after President Trump told the EPA to begin rewriting the 2015 regulation, as part of a broader effort to obliterate Obama’s efforts to make combating climate change a top priority.
A central piece of Obama’s environmental legacy, the Clean Power Plan aims to slash the greenhouse-gas emissions that scientists agree are fueling the planet’s rapid warming.
It also was an integral part of the commitment US officials made as part of a historic international climate accord signed in 2015 in Paris, from which Trump has said he intends to withdraw.
In a statement Monday, former EPA administrator Gina McCarthy, who shepherded the rule during Obama’s second term, said a proposal to repeal it ‘‘without any timeline or even a commitment to propose a rule to reduce carbon pollution, isn’t a step forward, it’s a wholesale retreat from EPA’s legal, scientific and moral obligation to address the threats of climate change.’’
‘‘The Supreme Court has concluded multiple times that EPA is obligated by law to move forward with action to regulate greenhouse gases, but this administration has no intention of following the law,’’ McCarthy said.