WASHINGTON -- The Environmental Protection Agency proposed new rules on Friday to reduce future carbon dioxide emissions from new power plants, a major step to address climate change that industry and some environmentalist say could all but end the construction of coal-fired plants in the United States.

Under the proposed rules, new coal plants would have to reduce emissions of heat-trapping carbon dioxide to 1,100 pounds per megawatt hour from the industry’s current range of 1,800 to 2,200 pounds per megawatt hour. Natural gas plants would have to meet a standard of 1,000 pounds of carbon per hour, easily achieved as many gas generators already emit less than that.

The rules are the most significant initiative to date by the Obama administration to deliver on a reinvigorated commitment to addressing climate change that the president made in a June speech at Georgetown University.

“By taking common-sense action to limit carbon pollution from new power plants, we can slow the effects of climate change and fulfill our obligation to ensure a safe and healthy environment for our children,” EPA Administrator Gina McCarthy said. “These standards will also spark the innovation we need to build the next generation of power plants, helping grow a more sustainable clean energy economy.”

For a new coal plant to meet the proposed emissions standard, it would have to use carbon capture and sequester technology, which entails scrubbing a fossil fuel before or after combustion and then storing the carbon dioxide deep underground or using it for operations such as recovering oil from partially depleted wells. The coal industry and its political allies insist that the technology is too expensive. As a result, coal plants would not be built and jobs in coal states eliminated.

“The president is leading a war on coal and what that really means for Kentucky families is a war on jobs,” said Senate minority leader Mitch McConnell (R-Ky.). “The announcement by the EPA is another back door attempt by President Obama to fulfill his long-term commitment to shut down our nation’s coal mines."

The long decline of coal jobs in Appalachia has been stoked by mechanization, loss of domestic heavy industry and most recently, the flood of cheap natural gas into power generation. But some environmentalists, such as Sierra Club Executive Director Michael Brune, agree that the new environmental rules would effectively bar new coal plants. “Can you build a coal plant after this? No,” Brune said. “It’s not commercially feasible to build a new coal plant, period. That’s why coal plants aren’t being built in the first place. When coal-burning utilities are forced to account for soot, smog, mercury and now, carbon, they can't compete and it widens the gap between coal and other fuels.”