(Bloomberg) -- Tesla Inc. employees at the carmaker’s factory outside Berlin are growing increasingly concerned about safety hazards and overwork, according to IG Metall, prompting more workers to join the German union.

More than 1,000 staff showed up at Tesla’s plant in Gruenheide on Monday near Berlin wearing stickers calling for “safe and fair work,” the union said. Roughly 12,000 people work at the site.

Tesla employees are complaining about poor conditions and safety hazards, including extreme workloads due to staff shortages and overly ambitious production targets, IG Metall said. The group, which has considerable influence at rivals including Volkswagen AG, has seen a spike in the number of Tesla workers joining its ranks.

A growing number of auto-industry workers are demanding better pay and job security in the shift to electric vehicles. The United Auto Workers union has launched a major strike targeting General Motors, Ford and Stellantis in the US, halting output at several factories. The concern is that EVs, which require fewer moving parts and workers to make, will cost jobs and reduce wages.

Read more: UAW Skips Strike Expansion, Paves Way for EV Plant 

Tesla Chief Executive Officer Elon Musk has shown little tolerance for unions. A day after a group of Tesla workers in Buffalo, New York, launched a unionization campaign early this year, the carmaker terminated them. Tesla has lost several National Labor Relations Board rulings the last couple years, including one in August 2022 related to restricting employees from wearing pro-union t-shirts.

Tesla didn’t respond to a request for comment. In Germany, the company has so far refused to sign the kind of wage agreements that are standard in Europe’s biggest economy, putting the carmaker on a collision course with the 2.2 million-member IG Metall.

“No one in Germany needs to hide their union membership,” said Dirk Schulze, an IG Metall district manager. “The German Constitution gives all employees the right to organize in a union and to openly stand up for it in the workplace — this also applies at Tesla.”

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