Workers at the largest power plant in Massachusetts have gone on strike over alleged public safety issues and concerns about working conditions.

Dozens of employees at Exelon Mystic Generating Station in Boston's Charlestown neighborhood started their strike Saturday morning, according to their union, the Utility Workers Union of America Local 369.

The 2,001-megawatt, oil and natural gas fired plant is owned by Illinois-based Exelon Power. A message seeking comment on the strike was left with the company on Sunday.

Exelon has repeatedly cut corners and deferred important maintenance upgrades at the plant, the union said in a statement. That jeopardizes the retention of highly-skilled, long-time employees, the union said.

"Running this vital plant is dangerous work which requires technical know-how. You need someone sitting at the control panel who knows what they're doing," Local 369 President Craig Pinkham said in a statement. "We're dealing with high-pressure gas, high-pressure steam, ammonia-fueled gas — many highly poisonous materials that require a high degree of expertise and experience."

During the strike, the plant is being run by management who lack the proper experience, the union said.