March 4 (UPI) -- Vermont Sen. Bernie Sanders joined a rally for organized labor at a Nissan auto plant in Mississippi on Saturday, calling on the Japanese automaker to drop its opposition to workers unionizing.
Sanders joined other liberal groups, including the Sierra Club and the NAACP, in signing a letter to Nissan, challenging the company to allow workers the right to freely decide whether to join the United Auto Workers, and to improve workplace safety at its plant in Canton, Miss.
"These workers have shown incredible courage in standing up and fighting back, and they deserve my support -- and I think they deserve support from progressives all across this country," Sanders told Bloomberg News on Friday.
Sanders said workers have been threatened with layoffs or the plant's closure if they vote in favor of joining the UAW and have been forced to attend anti-union meetings while at work, charges the company denied.
Workers at 42 of Nissan's 45 factories worldwide are unionized, but not at its three facilities in Mississippi and Tennessee.
The rally also featured actor and activist Danny Glover, who said in a statement that workers at Nissan's Mississippi factory are being mistreated.
"The company has committed rampant safety and health violations and denied its workers their basic right to vote for a union free from fear and intimidation," Glover said.
The federal Occupational Safety and Health Administration recently issued two citations for workplace safety hazards at the plant.
While Nissan acknowledged the safety complaints and said it is working with OSHA to resolve them, the company denied it has violated workers' rights to unionize.
"The allegations made by the union are totally false," Nissan spokesman Brian Brockman said in an email. "Nissan respects and values the Canton workforce, and our history reflects that we recognize the employees' rights to decide for themselves whether or not to have third-party representation."
The battle is a significant one for the UAW, which has faced shrinking membership and has largely failed to organize workers at U.S. factories operated by foreign auto companies, including Nissan, Honda, Toyota, Kia and Volkswagen.