The International Association of Machinists and Aerospace Workers, which represents thousands of workers at Bath Iron Works, is asking a federal judge to vacate an arbitrator’s recent decision in a contract dispute over the outsourcing of certain jobs.

In a complaint filed Thursday in U.S. District Court, the union alleges that arbitrator James Cooper sided with the company in order to secure future arbitration work.

BIW spokesman Matt Wickenheiser said in a written statement that Cooper’s decision was issued properly.

The contract dispute centers on the question of whether BIW can purchase certain ship components from third parties, rather than having them manufactured on site by BIW employees. The union has argued that purchasing the already-made components would violate a provision of the collective bargaining agreement between BIW and the union that prohibits the outsourcing of labor.

However, in February, Cooper presided over an arbitration proceeding to resolve the dispute and ultimately sided with the company.

The union alleges in its complaint that Cooper made a statement during the proceeding that indicated he was concerned about not being given any arbitration work by BIW since he sided with the union in a company smoking policy dispute in 2009.

Neither Cooper nor BIW had filed a response to the complaint in court as of noon Friday. Wickenheiser said via email that BIW should have the right to buy components instead of producing them if it makes the company more competitive.

The shipyard has been trying to streamline production costs to bid more competitively on a $10 billion contract for U.S. Coast Guard cutters. The bid is expected to be awarded in August.