Updated

The Obama administration's environmental agenda, long a target of American business, is beginning to take fire from some of the Democratic Party's most reliable supporters: Labor unions.

Several unions with strong influence in key states are demanding that the Environmental Protection Agency soften new regulations aimed at pollution associated with coal-fired power plants. Their contention: Roughly half a dozen rules expected to roll out within the next two years could put thousands of jobs in jeopardy and damage the party's 2012 election prospects.

"If the EPA issues regulations that cost jobs in Pennsylvania and Ohio, the Republicans will blast the President with it over and over," says Stewart Acuff, chief of staff to the president of the Utility Workers Union of America. "Not just the President. Every Democratic [lawmaker] from those states."

Several unions with strong influence in key states are demanding that the EPA soften new regulations aimed at pollution associated with coal-fired power plants.

A range of American companies that depend on fossil fuel-from coal and oil firms to manufacturers-have complained about the Obama EPA, one reason the administration has had tense relations with business. In meetings in recent days, representatives of electric power utilities that rely heavily on coal-fired plants, and some large unions, have taken their concerns to the White House. The companies and the unions have said a new regulation targeting mercury and other toxic pollutants, due to be proposed this week, could lead to higher electric bills, billions of dollars in new costs and the closing of plants that employ thousands of workers.

Now that labor unions are joining the chorus, the pressure on the agency is intensifying. Some Democrats, worried about potential job losses in industrial states, are already urging the EPA to slow down its push to combat climate change.

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