Thousands of Boeing workers have announced a strike starting Friday, an unprecedented move in 16 years that has partially halted production at the company’s Seattle-area facility. The strike follows the rejection of a new agreement proposed by the company, intended to replace a contract that expired at midnight Thursday.

Negotiations between the company’s management and the local machinists’ union had been ongoing since March 8, but the new agreement did not meet the workers’ approval. Voting results showed a 94.6% rejection of the agreement, with 96% of members voting in favor of the strike. The union, led by President Jon Holden, represents approximately 33,000 workers at the company’s Northwest U.S. facility, out of 170,000 employees at the Boeing Group.