Volkswagen’s factory in Chattanooga, 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.