In Germany, I thought it fitting to rent a car made by Opel, General Motors‘ European operation, which has lost billions of dollars over the past ten years. I was on my way to a factory in an industrial city called Bochum that GM eventually hopes to close.

GM’s Opel plant is the single largest employer in Bochum. Opel turned down my request for a factory visit, but union members were more than happy to show me the production line.

Markus Bauer and other workers oppose GM’s plans to close the factory. Bauer stood at an assembly point in a sweatshirt that essentially translates as: “We stay Bochum.” Bauer explained what it means: “Opel has to stay here in Bochum. Full stop.”

Unions are strong in Germany. At Opel and other carmakers here, union representatives hold half the seats on company boards. That allows workers to weigh in on big decisions. David Bailey, an auto industry expert at Coventry University, says that union power is one reason why — since the Second World War — not a single auto plant has closed in Germany.

“Companies haven’t actually looked to cut plants in Germany so far,” Bailey says. “That’s about to change.”

Opel has closed a plant in Belgium, and last month, Ford announced plans to close three factories in Belgium and the UK. But for Opel, shuttering the plant here in Bochum could come with a big price tag, according to Hans-Peter Merz at Bochum’s Chamber of Commerce.

“In Germany, this is very expensive — to lay off people,” says Merz. “You can’t just switch off the light and go home.”

He says, first, GM has to negotiate a large pay off for Opel workers. Then, the company is required to retrain those workers and clean up the factory site. All added up, Merz says, this could be the most expensive factory GM has ever closed.