Boeing denied misconduct by its managers afterb a union representing engineers and technical workers accused the planemaker's security staff of intimidating some members over labor contract votes.
"The union has not shared the specifics of these allegations with us. But throughout negotiations, Boeing has been respectful of the process. We don't believe our managers have engaged in any misconduct," Boeing spokesman Doug Alder told Reuters.
Boeing, which is currently beset by battery problems on its Dreamliner jets, is locked in a labor contract dispute with the union that represents its 23,000 engineers.
The new contract proposed by Boeing is now being voted on by union members. The ballots mailed on Feb. 5 recommend members reject the "best and final" contract that Boeing offered on Jan. 17. The votes will be tallied on Feb. 19.
The Society of Professional Engineering Employees in Aerospace (SPEEA) said that the complaint filed with National Labor Relations Board includes reports of managers holding mandatory meetings with employees to "interrogate and intimidate them regarding the current contract votes."
The union also said late on Wednesday that some of its members were stopped by the planemaker's security personnel from distributing leaflets on a labor contract ballot at the company's Everett factory.
"We are extremely disappointed in the company's misconduct," Ray Goforth, SPEEA executive director, said in a statement.
Boeing's offer extends the terms of the previous contract for another four years and includes 5 percent annual pay raises for professional and technical workers.
However, the union has balked at a Boeing contract that it says would cut the growth rate of compensation of professional and technical employees. Boeing says its latest offer is much improved over its initial proposal and reflects a tough competitive environment.
In October, SPEEA accused the airplane maker of videotaping members marching for contract talks and of seizing members' cameras and deleting photos. The labor relations board is yet to give a verdict on the complaint.