Boeing’s largest union rejected a second labor contract offer, extending a strike impacting 33,000 workers. Boeing reported a $6.1 billion loss, complicating CEO Kelly Ortberg’s efforts to stabilize the company amid strikes.

Striking Boeing workers have voted to reject a new offer from the aviation giant, which included a 35% pay rise over four years. The International Association of Machinists (IAM) union said 64% of its striking members voted against the proposed deal.

Sixty-four percent of those who voted cast a ballot to reject the proposed deal, which Boeing had hoped would be enough to end a nearly six-week walkout.