More than 300 union members and their families from Ohio, Pennsylvania and West Virginia gathered at the Environmental Protection Agency's headquarters Tuesday to protest a proposal to limit carbon emissions from coal-fired power plants that they said would kill jobs in Appalachia.

Many of the protesters were reliable Democratic voters who said they were venting frustration not with their party, but rather with an Obama administration that they say is pummeling their communities with too-stringent regulations.

"The United States Senate is controlled by Democrats, and these rules could not pass the United States Senate," said Cecil Roberts, president of the United Mine Workers of America, on a gloomy and overcast day in Washington.

The proposal aims to slash electricity-sector emissions 30 percent below 2005 levels by 2030. It has riled coal-mining communities that were already ailing from decades of job declines and, more recently, competition from cheap, cleaner-burning natural gas that is prompting coal mine closures.

The industry has pointed its finger at President Obama's EPA for recent struggles. The mine workers' union experience is instructive — it endorsed Obama in 2008, but sat out his re-election.

"There were some promises made, and we didn't endorse anyone in 2012 because those promises weren't fulfilled," David Jackson, a life-long Democrat and president of UMWA Local 1713 in southwest West Virginia, told the Washington Examiner. "We don't get that from all Democrats. We just happen to get that from our president."

The EPA says coal will still provide 30 percent of the nation's power, down from about 42 percent today, when the power plant rule is fully implemented in 2030. And the agency has in recent weeks touted the economic benefits of the proposal, which it says will spark innovation in green technologies, reduce healthcare spending and blunt the costly effects of climate change. Most scientists blame the burning of fossil fuels for creating the greenhouse gases that are exacerbating climate change.

"How every individual state responds in terms of developing a plan is going to be up to them," EPA Administrator Gina McCarthy told reporters at a recent Washington event. "And I think they have great opportunities to make this both as a state and locally the best approach for them economically and from an energy perspective."

Coal production in Central Appalachia, which includes West Virginia and Ohio, peaked in 1997 at 290 million short tons. It hit 133 million short tons last year, according to data from the federal U.S. Energy Information Administration. EIA says production will fall below 100 million short tons for good in 2023, dropping to 80.5 million short tons in 2040.

To communities in Appalachia that have dealt with year after year of job losses, the EPA proposal is just another thorn in their side. While EPA regulations haven't caused the region's recent struggles — even Jackson admitted more regulation was necessary — those attending the rally said the rules would accelerate trends.

"We are fighting for our livelihood," James Gibbs, the international at-large vice president for UMWA, told the crowd.

Gibbs emphasized voting power as a way to show the administration and other lawmakers that the EPA regulations were untenable.

"This is our election. We need to take back this country," Gibbs said. "We have got to get out and take our people to the polls."

That doesn't mean union workers are looking to flip to support Republicans, much like many voters in the rest of some once-blue Appalachian districts.

Jim Byard, a 76-year-old retiree from Mannington, W.Va., told the Examiner he would keep voting for Democrats because he was concerned about right-to-work legislation and pension changes that have cleared GOP-held capitols in recent years.

"They're trying to break our union and take everything away from us. If we lose our healthcare and pensions, where are we at?" he said. "I don't question my party. Not a bit."

Mel Arnold, on the other hand, said policies like the EPA power plant proposal are making it harder for him to continue voting Democratic. But the 74-year-old Zanesville, Ohio, resident said he wasn't ready to make a switch.

"It's not good," Arnold told the Examiner. "Politicians are — I'm not too crazy about any of them."