The National Labor Relations Board decided to uphold a ruling that Mercedes violated federal labor laws by stopping United Auto Workers union supporters from handing out literature inside its Alabama plant.

The ruling, made by the three-member NLRB panel, forces Mercedes to update its employee handbook to say that company workers are allowed to discuss union issues during non-work times and they can "solicit their colleagues in mixed-use areas like team centers and atriums," according to the Associated Press.

The automaker must also post notices at the plant, located near Tuscaloosa, to acknowledge the violation and to reaffirm that management will not "interfere with, restrain, or coerce" workers looking to unionize the facility.

"We appreciate the ruling by the National Labor Relations Board," Kirk Garner, who has worked at the Mercedes plant since 2000, said in an email to the AP on Monday. "Still, it's unfortunate that Mercedes-Benz had to be ordered to simply allow workers to discuss their right to organize."

"We're hopeful it can be a turning point for honoring workers' rights in Alabama, as Daimler does elsewhere in the U.S. and around the world," he added.

Garner was a witness in the NLRB case and is a member of the newly formed UAW Local 112 that is looking to gain representation at the plant.

Mercedes parent Daimler has long said that it is neutral when it comes to unions, and plant spokeswoman Felyicia Jerald added on Monday that the NLRB panel had agreed with the previous decision to throw out other worker complaints that said they had been "threatened or harassed" for supporting the union.

Jaerald said that the 2014 employee handbook is already updated to address "unclear" provisions.

"We clearly feel there are certain places in the plant that are work places, and not places where we would want materials like that being distributed, regardless of whether that's for or against the union," Jason Hoff, the plant's president and CEO, said in a statement to reporters in September. "It has nothing really to do with being against or for the UAW or any other union."

The Alabama plant started making Mercedes' bestselling C-Class this summer, making Mercedes the first German automaker to assemble a luxury Sedan in the U.S. The automaker will add 1,400 full-time positions at the plant to continue production of the C-Class and to make a new SUV.

The plant, which opened in 1997, employs about 3,400 workers, according to the AP.

See Now: OnePlus 6: How Different Will It Be From OnePlus 5?