BATH – Bath Iron Works and its largest union have reached a tentative contract agreement that members will vote on Sunday.

Neither the shipyard nor Machinists Local S6 would comment on the specifics of the three-year proposal, although a union spokesman said it contained provisions to help control workers’ health care costs.

“Health care is a national crisis right now, so even maintaining any of the provisions we had in the original agreement was very important. I think it’s safe to say that they were very good negotiations,” said John Carr of the international Machinists union.

Members will meet Sunday at the Augusta Civic Center to vote on the contract hours before the current four-year agreement expires at midnight.

The negotiations were conducted at a time of turmoil within Local S6, whose top officers have been suspended by the parent union as it conducts an internal investigation into allegations ranging from financial mismanagement to pornography on computers.

The four officers have filed a federal lawsuit against the international union. The lawyer representing the officers cautioned that discord in the union ranks could sway members to vote against ratification, even if the contract is a good one.

“I’ve talked to the attorney for BIW and let him know how dangerous the situation could be – if anything bad comes out of the negotiations or even mediocre, the members could react emotionally,” said Leon Rosenblatt of West Hartford, Conn. “The last thing anybody would want is an unnecessary strike.”