Chris Pizzello / AP Tesla CEO Elon Musk said employees at the company's production plant haven't unionized because "they just don't want to" on Sunday. A unionization effort at the company's Fremont, California, factory began in 2017, and the United Auto Workers Union filed a complaint with the National Labor Relations Board claiming Tesla fired employees who had attempted to unionize. Tesla and Musk have denied claims of retaliation toward pro-union employees. Tesla CEO Elon Musk said employees at the company's production plant haven't unionized because "they just don't want to" on Sunday. "They can form a union whenever they want & there’s nothing I can do to stop them," he wrote.