Boeing workers manufacturing fighter jets to strike at midnight on Monday.

Boeing’s fighter jet manufacturing workers are planning to go on strike starting midnight on Monday, August 4th, as the company failed to reach an agreement with the union workers on a four-year work contract.

The International Association of Machinists and Aerospace Workers (IAM) District Lodge 837, based in St. Louis, Missouri, announced on Sunday that approximately 3,200 workers across three Boeing facilities voted to reject the latest version of the four-year labor agreement offered by the company. The three Boeing facilities are located in St. Louis, St. Charles in Missouri, and Mascoutah in Illinois.

Tom Boelling, the business representative for the union district lodge, stated in a press release, “Members of the International Association of Machinists and Aerospace Workers District Lodge 837 have clearly expressed their demands, and they deserve a contract that reflects their skills, dedication, and critical role in our national defense.”

The vote came after union members rejected a previous proposal put forward by Boeing last week, which would have increased workers’ wages by 20% over the next four years.

According to Boeing, the company sent a new contract proposal to the union last week, which included minor adjustments to compensation that would benefit senior union members. The proposal also retained the current overtime policies, whereas Boeing had previously proposed changes to these policies in the previous contract proposal.

Union leadership had initially recommended accepting the new proposal, calling it a “landmark agreement” and stating that it would improve healthcare, pension, and overtime benefits.

However, after a week-long cooling-off period, union members ultimately voted to reject Boeing’s new proposal.

Dan Gillian, Vice President and General Manager of Boeing’s Air Dominance program, expressed disappointment in the employees’ rejection of the latest proposal, stating, “We are prepared for the strike and have implemented contingency plans to ensure that non-striking employees can continue to support our customers.”

The last strike by the union occurred in 1996 and lasted for 99 days.