The National Labor Relations Board (NLRB) said today it is investigating six unfair labor practice charges against Mercedes-Benz by the United Auto Workers.

Workers at the German automaker’s Vance factory are scheduled to begin voting next week on whether they will be represented by the UAW.

Vote totals are expected Friday.

In addition, the NLRB is also investigating three charges filed against Hyundai’s Montgomery plant.

The NLRB’s Region 10 Atlanta office is handling the charges against Mercedes.

They allege that the factory disciplined employees for discussing unionization at work, prohibited distribution of union materials and paraphernalia, surveilled employees, discharged union supporters, forced employees to attend captive audience meetings, and made statements suggesting that union activity is futile.

Earlier this month, the UAW announced it was filing charges but the individual allegations were not immediately clear on the NLRB website.

In a statement, Mercedes-Benz U.S. International (MBUSI) said at the time that it has “not interfered with or retaliated against any Team Member in their right to pursue union representation, and we do not agree that the claims have any merit.”

“We look forward to presenting our case to the NLRB,” Mercedes-Benz stated. “Additionally, MBUSI rejects claims that it has denied any Team Member leave for their union affiliation. Following the UAW’s nationwide campaign to increase its membership, MBUSI wants to ensure its team members make an informed decision. MBUSI has a strong record of success over the past 25+ years operating as One Team in Alabama. Central to our success is our positive team culture that includes an open-door policy. MBUSI has a proven record of competitively compensating Team Members and providing many additional benefits. We believe open and direct communication with our Team Members is the best path forward to ensure continued success.”

Once the NRLB’s investigations are complete, its regional director will determine if the allegations have merit and seek remedies.

UAW dropped its unfair labor practice charges against Volkswagen once an election at the Chattanooga plant certified the union as bargaining agent.

In April, the UAW announced it was bringing charges against Mercedes in Germany for violating a law that forbids companies from non-compliance with labor protections, as well as discrimination and withholding of wages.

NLRB also said its Region 15 New Orleans office is investigating three charges against Hyundai in Montgomery.

Those charges allege that Hyundai fired an employee, confiscated, and prohibited distribution of union materials, and intimidated union supporters.

Mercedes-Benz, along with Hyundai’s Montgomery plant, are part of an ongoing campaign by the auto union to organize in Southern plants historically resistant to organizing.

Hyundai, in a statement, said the NLRB has not yet initiated any formal investigation into the claims. It denies the allegations, “has not and will not interfer with or retaliate against any Team Member in their right to pursue union representation,” the company said.

“HMMA team members may choose to join a union or not as is their legal right, and this has been true since our plant opened in 2005,” the company said. “Since then, our team members have continuously demonstrated their preference for our ‘Team Built Team Strong’ philosophy providing opportunities to be personally valued and respected and for their own voice to be heard in direct dialogue with one another.”