Correction: An earlier version of the article misstated the 2012 figure for greenhouse gas emissions from U.S. power plants. It was 2.1 billion metric tons, not 2.1 million. This version has been corrected.

Greenhouse gas emissions from power plants and other industrial facilities declined by 4.5 percent from 2011 to 2012 as utilities continued to switch from coal to natural gas to generate electricity and produced slightly less power overall, the Environmental Protection Agency reported Wednesday.

Greenhouse gas emissions from these sources have declined by 10 percent in the two years since the EPA began compiling the data in 2010.

Power plants poured about 2.1 billion metric tons of heat-trapping gases such as carbon dioxide into the atmosphere last year, about 31 percent of the total U.S. production of such gases. Power plants release far more greenhouse gas than any other type of facility reviewed by the EPA, including refineries, chemical plants, and oil and gas exploration equipment.

“EPA is supporting President Obama’s climate action plan by providing the high-quality data necessary to help guide common-sense solutions to address climate change,” EPA Administrator Gina McCarthy said in a statement. “Putting this data in the hands of the public increases transparency, supports accountability, and unlocks innovation.”

Peter Zalzal, staff lawyer for the Environmental Defense Fund, said the data show that “we’ve had some emissions decreases, which is a good thing, but there are still significant sources of pollution out there.”

Noting continued leaks of methane and vented natural gas emission from oil and gas facilities, Zalzal said that “we can make tremendous progress in just applying common-sense solutions to our existing infrastructure,” such as plugging methane leaks during exploration for natural gas. Although there is much less methane than carbon dioxide released into the atmosphere, it is 20 times more effective at trapping heat.

Tom Kuhn, president of Edison Electric Institute, which represents electric utilities, said, “The utility industry understands the importance of reducing emissions and has been a leader in reducing greenhouse gas emissions over the last two decades.”

The American Petroleum Institute, which represents the oil and gas industry, said in a statement that “the EPA report shows that the U.S. energy revolution, driven by hydraulic fracturing and horizontal drilling, has been instrumental in delivering the natural gas that is helping to lower emissions, create jobs and energize the economy.”

In September, the EPA issued rules to strictly limit the amount of carbon that future coal- and gas-fired power plants can release, proposing a standard that will be difficult for coal plants to meet without substantial investment in new technology.

The agency is scheduled to issue a similar ceiling for existing power plants in June, and officials are holding meetings nationwide to hear public comment about what that level should be.

The data released Wednesday make clear how important regulating power plants is to the U.S. goal of reducing greenhouse gas emissions 17 percent by 2020. The 1,611 power plants reporting to the EPA were responsible for two-thirds of the heat-trapping gases released by the nine industry sectors in the report.

In second place were producers, transporters and distributors of petroleum and natural gas, which released about 10 percent as much as the utility sector.

The EPA also released a map that shows where facilities are located and how much carbon pollution they emit.

According to Zalzal, the top emitter is an oil-and-coal-powered plant in Juliette, Ga., that put 21.8 million metric tons of gases into the atmosphere in 2012.