SHIPPINGPORT — Union representatives for workers at FirstEnergy Corp.’s Bruce Mansfield coal-fired plant walked out on negotiations Monday amid accusations that the company has violated the current contract and wants to end health care subsidies for retirees.

“How can we move forward with a new contract when you have already violated the current agreement?” asked Herman Marshman Jr., the president of International Brotherhood of Electrical Workers Local 272. “You can’t have an agreement if nobody’s abiding by the agreement.”

After two negotiating sessions last week, Marshman said the union walked out on the latest one Monday angry over FirstEnergy’s approach. The current contract expires Feb. 15, he said.

FirstEnergy has violated the agreement 29 times, Marshman claimed, endangering the safety of employees. One example he cited was the company having emergency medical technicians assigned clerical work instead of being positioned to respond to a crisis.

“Our issue is that if they’re not on their station … then they have to stop doing whatever they’re doing and go back to their station to get their equipment to attend to the emergency,” said Marshman, a 34-year employee and plant system operator.

As for retirees, Marshman said FirstEnergy wants to eliminate health care subsidies for them as of Jan. 1, 2015. That, he said, is just one of 20 concessions the company has proposed.

Marshman said there are 283 union workers at the plant and several hundred retirees. Stephanie Walton, a FirstEnergy spokeswoman, would not respond to Marshman’s comments Tuesday, but did say company representatives would attend a negotiating session scheduled for today.

Marshman said the union would attend that session and trade concerns with the FirstEnergy team, but it would not enter into substantive negotiations.

Also, Marshman said he and a national IBEW representative would meet with FirstEnergy officials Friday in an effort to resolve “the stalemate” that has stalled talks.