Workers at General Motors and LG Energy’s joint venture battery cell factory in Ohio have voted strongly in favor of joining the United Auto Workers (UAW) union, it was revealed today. Among them, 710 voted in favor of joining, 16 voted against, and one vote was voided.

Our entire union welcomes our latest members from Ultium,” says UAW President Ray Curry. “As the auto industry transitions to electric vehicles, new workers entering the auto sector at plants like Ultium are thinking about their value and worth. This vote shows that they want to be a part of maintaining the high standards and wages that UAW members have built in the auto industry.”

Although workers at General Motors’ factories are represented by the union, that is still not a guarantee for all workers at the new joint venture called Ultium Cells LLC. The question of whether or not these new workers would join the union was an important one for the UAW, and a test of its ability to organize workers in the burgeoning field of EV battery manufacturing.

Read: UAW Accuses GM Ultium Joint Venture Battery Plants Of Impeding Unionizing Efforts

Ultium said it respects “the decision of our Ohio workforce supporting representation by the UAW. We look forward to a positive working relationship with the UAW.”

The union petitioned to represent the roughly 900 workers at the Ultium Cells LLC plant near Cleveland in October. The majority of workers signed cards authorizing the organization to represent them as part of the union’s region 2B, which led to this vote.

“Region 2B has stood with Ultium workers since the moment they said they wanted to form their organizing committees,” said Wayne Blanchard, UAW Region 2B Director. “Their hard work and the support of Region 2B members and staff have led to this powerful victory. Special thanks to the retirees of Local 1112 who would open the hall at any hour to help Ultium workers meet.”

Production at the Ohio Ultium Cells plant started in August, and it is the first of at least four planned for the U.S. The joint venture company has said that it will build a plant in Michigan and is looking at another in Indiana.

The toughest test of the UAW’s ability to organize is likely to come when it seeks to represent workers at Ultium Cells’ fourth plant, which is planned for Tennessee, where general support for unions is weaker.