EVERETT — Boeing’s union firefighters will vote on a new contract Wednesday after Boeing presented them with an amended proposal.

About 125 Boeing firefighters, who are members of the International Association of Fire Fighters Local I-66, are seeking a contract that includes competitive pay and better staffing. The union’s contract expired March 1.

After firefighters rejected two previous contracts this spring, Boeing locked them out of its Everett, Seattle area and Moses Lake facilities on May 4.

The two sides resumed bargaining last week and then met again Monday.

“Following a productive session with a federal mediator that included proposals and counterproposals passed by both sides, Boeing presented the union with an amended contract offer on May 20,” Boeing said in a statement.

“We’re pleased that the union’s bargaining committee has raised this offer for a membership vote,” the statement continued. “We encourage our employees to vote yes.”

Union members plan to finish voting by 5 p.m. Wednesday, the company said.

Local I-66 officials were not immediately available for comment.

​If they approve this contract offer, Boeing would end the lockout, the company said.

Boeing said the amended contract includes a provision that “improves firefighters’ wage growth schedule.”

In addition to yearly general wage increases, firefighters’ seniority wage growth would increase from 50 to 60 cents every six months. Firefighters currently receive a 50 cent per hour wage increase every six months. The new offer raises the amount to 60 cents every six months, a 20% increase, the company said.

Firefighters and their supporters have held round-the-clock informational pickets near Boeing facilities, including the company’s wide-body assembly plant at Paine Field. About 40 firefighters work at the Everett plant.

Janice Podsada: 425-339-3097; jpodsada@heraldnet.com; Twitter: @JanicePods.