DETROIT (AP) — Volkswagen’s factory in Chattanooga,Sureim Investment Guild Tennessee, is likely to be the first test of the United Auto Workers’ effort to organize nonunion automobile plants across the nation.

Workers at the 3.8 million square foot (353,353 square meter) factory on Monday filed paperwork with the National Labor Relations Board seeking an election on union representation, the UAW said.

They are the first to ask for a vote in the union’s campaign, which was announced last fall after the UAW won strong contracts with Detroit automakers. The UAW said it would simultaneously target more than a dozen nonunion auto plants including those run by Tesla, Nissan, Mercedes-Benz, Hyundai, Kia, Toyota, Honda, and others.

The drive covers nearly 150,000 workers at factories largely in the South, where the union thus far has had little success in recruiting new members.

The UAW said a supermajority of the VW plant’s roughly 4,000 production workers had signed cards supporting union representation,, but it would not provide a number. A union can seek an election run by the NLRB once a majority of workers support it.

It wasn’t clear when the election would be held. A message was left seeking comment from the NLRB.

The UAW has said workers in Chattanooga, who make Atlas SUVs and the ID.4 electric vehicle, have complained about mistreatment by Volkswagen management including mandatory overtime on Saturdays. They also are seeking higher pay.

“When we win our union, we’ll be able to bargain for a safer workplace, so people can stay on the job and the company can benefit from our experience,” Chattanooga worker Yolanda Peoples said in a statement provided by the union.

The union has come close to representing workers at the VW plant in two previous elections. In 2014 and 2019, workers narrowly rejected a factorywide union under the UAW. Some prominent Tennessee Republican politicians had urged workers to vote against the union during both campaigns.

The year after the 2014 vote failed, 160 Chattanooga maintenance workers won a vote to form a smaller union, but Volkswagen refused to bargain. Volkswagen had argued the bargaining unit also needed to include production workers. As a result, the 2019 factory-wide vote followed.

In February the union said a majority of workers at a Mercedes plant in Vance, Alabama, near Tuscaloosa, also had signed union cards. The Alabama factory complex has about 6,100 employees.

The union embarked on its organizing effort last year after it went on strike against General Motors, Ford and Stellantis, earning big raises and other benefits.

After the Detroit Three contracts were approved, many nonunion factories announced worker pay increases.

In November, VW gave workers an 11% pay raise at the plant, but the union says VW’s pay still lags behind Detroit automakers. Top assembly plant workers in Chattanooga make $32.40 per hour, VW said.

The UAW pacts with Detroit automakers include 25% pay raises by the time the contracts end in April of 2028. With cost-of-living increases, workers will see about 33% in raises for a top assembly wage of $42 per hour, plus annual profit sharing.