Autoworkers at a Toyota engine plant in Troy, Missouri, have signed up 30 percent of their thousand coworkers to join the United Auto Workers (UAW) — a first at Toyota, the world’s largest automaker, on the heels of the union’s announcements of organizing campaigns at Volkswagen, Hyundai, and Mercedes-Benz.

Workers at the plant just outside St Louis build 2.6 million cylinder heads per year. Should they stop building them, it would cut off supplies for all of the company’s engine plants in North America. Toyota is still working to build up its supply of chips and other inventory, following pandemic lockdowns and global supply chain snarls.

In the body of a vehicle, these cylinder heads are as essential as human lungs, controlling the flow of air and fuel into the combustion chamber, powering a vehicle’s performance on the road.