BATH, Maine — A second union at Bath Iron Works has become embroiled in a reportedly hostile dispute with BIW President Fred Harris about a proposal to contract out work instead of filling vacant union jobs to address a backlog of work, even as the shipyard’s largest union continues arbitration about the same issue.

One day before officials from Local S6 of the machinists union return to arbitration about a controversial proposal to cross-train employees, the president of Local S7 of the International Association of Machinists and Aerospace Workers, Dan Loudermilk, said he was called to a private meeting with Harris on Thursday morning that ended with Loudermilk refusing to shake Harris’ hand.

Loudermilk said the meeting deteriorated into name-calling on both sides, and he said Harris “threatened to shut down the union.”

“It’s a hollow threat,” Loudermilk said. “But it just goes to the nature of Fred and his bullying.”

Harris had not responded to a request for comment by 7:45 p.m. Thursday.

Loudermilk, whose union represents 211 workers, said just hours after the meeting that the company has refused to fill 11 existing jobs that have remained vacant since December.

According to a June 9 memo from Loudermilk to Local S7 membership, there is a backlog of 1,500 work orders “allegedly holding up production … because production does not have the manning to initiate the work.”

As an alternative to using contract workers, the company proposed temporarily assigning 15 Local S6 members to Local S7 for 12 weeks to alleviate the backlog, but Loudermilk said that offer was not accepted.

The union argued that allowing the loan to address the backlog would “just speed us toward” an anticipated October layoff.

The union is preparing to file a grievance, but Loudermilk said that despite a contractual obligation for both sides to participate in “consensus decision making” followed, if necessary, by arbitration, he was told salaried employees were at the shipyard during the weekend performing work typically done by S7 workers.

On Tuesday, Seth Fairbanks, director of labor relations for the company, wrote to Loudermilk requesting the consensus decision making process be started.

“While we have attempted to work through multiple solutions to resolve these issues with the union, it appears that options may be limited at this point,” Fairbanks wrote.

In a response the same day, Loudermilk wrote, “The only attempts to resolve this issue by the company was with ultimatums, threats and ‘my way is the only way.’ The local made several attempts to negotiate in a good faith manner, which the company rejected.”

Meanwhile, Local S7 workers are watching the labor dispute between management and Local S6, Loudermilk said, “because we suspect there’s going to be a strike. If Local S6 goes on strike, there’s going to be very little work happening in the shipyard, and they won’t need as many of us, so there will be layoffs then.”

In 2000, Local S6 workers went on strike for 55 days, fighting to eliminate a policy of cross-training workers, known as “associated functions” — a policy the union is fighting against again.

Don Ames, a trade planner and member of Local S7, said Thursday that he hasn’t seen morale at the shipyard so low in the 37 years he’s worked there.

“When [former BIW president] Jeff Geiger was here, he was all about keeping Maine jobs and keeping people here,” Ames said. “With the guy we’ve got now, he’s all about outsourcing stuff. It’s a different attitude. They’re supposed to be negotiating in good faith, but it’s hard to believe whether they’re telling the truth or it’s a trick.”

On Thursday afternoon, a spokeswoman for Sens. Susan Collins, R-Maine, and Angus King, I-Maine, said in a statement, “Senators Collins and King remain committed to advocating for Bath Iron Works, as evidenced by their work on the Senate Defense Appropriations Subcommittee and Armed Services Committee. As the men and women of BIW build the highest quality and most advanced destroyers in the world, Senators Collins and King continue to urge labor and management to work together to resolve their differences.”