Boeing Co. said it had submitted a revised four-year labor proposal to the International Association of Machinists and Aerospace Workers District 837, covering about 3,200 employees at its defense plants near St. Louis. The package maintained a 20% cumulative wage increase, added minor tweaks benefiting senior workers and kept existing overtime rules. It also included a one-time $5,000 ratification bonus that would lapse if the deal was not approved by 11:59 p.m. on 3 Aug., according to the company. Union members voted on 3 Aug. to reject the offer, clearing the way for their first strike since 1996. Unless the two sides reach a new agreement, picket lines will go up at 12:00 a.m. Central Time on 4 Aug. Boeing said in an emailed statement that the proposal is “the richest we’ve ever presented for IAM 837” and that contingency plans are in place to limit production disruptions, while the union said the terms still fall short of workers’ expectations. A work stoppage would idle facilities that assemble F-15 fighter jets, T-7A trainer aircraft and missiles, risking delays to U.S. defense programs at a time when the company is expanding its military manufacturing footprint in Missouri. The dispute adds to the operational challenges facing Boeing as it seeks to stabilize its wider business after several difficult years.