Calling climate change “one of the most significant public health challenges of our time,” the Obama administration on Friday announced new regulations to cut carbon pollution from coal and natural gas plants, a move that could speed the closure of aging coal plants in South Carolina and elsewhere across the country.

The rules have been in the works for years and are the first step in President Obama’s climate change package announced in June. Gina McCarthy, administrator of the Environmental Protection Agency, said in a statement that the rules would help slow global warming, make the nation’s skies cleaner and “spark the innovation we need to build the next generation of power plants.”

Opponents have called the admin-istration’s stance a “war”on coal. “We’re letting the EPA drive jobs out of the country,” said state Sen. Paul Campbell, R-Goose Creek, a former board member of Santee Cooper, a state-owned utility with a huge coal-fired plant in Cross.

“This isn’t about a war on coal, it’s about leveling the battlefield between coal and every other energy source out there,” said Blan Holman, an attorney for the Southern Environmental Law Center in Charleston. “For decades coal has gotten a free pass to pollute and taxpayer subsidies to produce, giving it unfair advantages against competitors.”

The rules could have implications in South Carolina’s changing power-generation mix. Concerned about new pollution restrictions, the state’s utilities already had decided to shutter older plants and focus more on natural gas and nuclear power. The state currently has nine coal-fired power plants, but that number is expected to decrease. Earlier this year, SCANA said it would shut down its Canadys station near Walterboro by the end of the year, four years ahead of schedule.

Coal-fired power plants are the nation’s largest source of greenhouse gases, and the new rules come at a time when many utilities are finding it cheaper to produce power using natural gas. Prices for natural gas have fallen dramatically with the advent of hydraulic fracturing, or fracking. The EPA issued its new Clean Air Act rules after receiving more than 2.5 million public comments from supporters and opponents.

The rules also will affect new natural gas plants. Emissions from new gas plants would be limited to 1,000 pounds of CO2 per megawatt hour or less, which is about what a modern plant now produces. New coal plants, however, would be limited to emissions of 1,100 pounds of CO2 per megawatt hour, which would force utilities to find ways to capture and store excess carbon dioxide, an expensive technology.

Mollie Gore, a spokeswoman for Santee Cooper, said utility leaders believe greenhouse gases should be addressed by Congress, not the Obama administration, and that the Clean Air Act shouldn’t be used to regulate carbon dioxide. Referring to the carbon capture and storage technology, she said that the “EPA has in fact proposed a standard that requires the use of unproven technology in new coal-fired power plants. This will ultimately add to already-increasing costs to produce power for utilities — and our customers.”

“The bottom line is that there’s a cost to carbon that’s not being captured in electricity prices,” said Hamilton Davis of the Coastal Conservation League, but added that the regulations mostly involve new plants. “We don’t have any proposed coal plants in South Carolina and hopefully we won’t see any, so it shouldn’t affect us.”