Constellium and the UAW returned to the bargaining table Thursday, strike coordinator Michael Shumaker told Automotive News. About 160 members of UAW Local 174 began striking Wednesday at the Constellium plant in suburban Detroit that supplies aluminum components to Ford.

Workers are concerned about frequent oil spills and other safety issues in the plant as well as pay raises that have not kept up with the cost of living, Michael Murray, a 10-year employee, told Automotive News.

“There’s a lot of safety concerns inside and we have outwardly brought it to their attention and they fail to fix it. We’ve had people falling and hurting themselves,” Murray said.

The contract was originally set to expire May 13. The UAW extended it through May 16 before striking May 17. The UAW wanted to negotiate during that extension but were not able to schedule a meeting with the company, Shumaker said.

A spokeperson for Constellium did not respond to a request for comment.

Negotiations also are ongoing at a Clarios plant in suburban Toledo where about 500 members of UAW Local 12 are on strike. The plant supplies batteries to Ford and General Motors. The union’s primary concerns are overtime pay and schedule changes.

Clarios has implemented contingency plans to compensate for the striking workers’ absence, Corey Graven, Clarios vice president for U.S. operations and supply chain, said Thursday. The company has continued making deliveries by shifting some of the facility’s load to other plants and bringing in temporary workers and Clarios employees from other plants to Toledo.

“We remain committed to bargaining in good faith, appreciate the professionalism of the union negotiating team and remain confident we will reach a fair agreement to increase wages and improve work-life balance for our employees,” Graven said.

UAW Region 2B Director David Green said Wednesday he believed Clarios is working with the bargaining committee to get a fair contract.

The two strikes are taking place as the Detroit 3 automakers prepare for companywide contract talks with both the UAW and Unifor in Canada later this summer.

Constellium, of Paris, France, ranks No. 84 on Automotive News‘ list of the top 100 global parts suppliers, with estimated worldwide sales to automakers of $1.9 billion in its 2021 fiscal year.

Clarios, based in Milwaukee and formerly part of Johnson Controls Inc., ranks No. 75 on that list with estimated worldwide sales to automakers of $2.5 billion in its 2021 fiscal year.

Paige Hodder contributed to this report.