Among the states, Pennsylvania facilities reported the second-highest emissions amounts. Highly industrialized New Jersey was far down the list, with emissions comparable to those of Montana.
Users can sort the data by facility, industrial sector, type of gas emitted, and location - including views by state and by county. The database is at http://ghgdata.epa.gov
Gina McCarthy, assistant administrator for the EPA's Office of Air and Radiation, said the data tool was a powerful public resource for individuals, communities, businesses, and investors.
"What we can bank on is that better information will lead to a better-informed public, which will lead to better environmental protection," she said.
Mark Durbin, a FirstEnergy spokesman, said he wasn't surprised that Bruce Mansfield ranked high.
"There is a direct correlation of the amount of CO2 emitted with the amount of coal combusted," he said. Since Bruce Mansfield "is one of the largest coal-fired plants in the nation, it stands to reason that the CO2 we report is a large number."
The 2,490 megawatts of electricity the plant produces, he said, is enough to power about 1.5 million homes.
What the list doesn't show, he said, is that Bruce Mansfield is also one of the most highly controlled power plants, with equipment to reduce mercury, sulfur dioxide, and other emissions.
While these pollutants have come under increasing regulation, carbon dioxide has not, although many experts expect that federal legislation or regulation will eventually target power-plant emissions of the gas.
Greenhouse gases contribute to climate change. President Obama has announced the goal to reduce U.S. emissions to 20 percent below 1990 levels by 2020.
