SpaceX owner and Tesla CEO Elon Musk gestures during a conversation at the E3 gaming convention in Los Angeles, June 13, 2019.

Tesla must reimburse workers and hold a public meeting in its factory explaining how it broke labor laws after unfairly preventing employees from unionizing, a judge ruled in a National Labor Relations Board complaint Friday, according to media reports.

Administrative Law Judge Amita Baman Tracy found that CEO Elon Musk violated national labor laws when he implied via tweet that Tesla workers who unionized would have to give up their company stock options.

Tweet

The judge also found that Musk wrongfully terminated one worker for union activity, ordering the company to reinstate them and offer back-pay. The electric car maker also wrongfully issued a warning to another union supporter.

The company must hold a meeting at its assembly plant in Fremont, California, and Musk or the NLRB will read a statement explaining how Tesla broke the law. Musk must attend, the judge ruled.

The ruling stems from complaints originally filed by the United Auto Workers. An appeal is likely, Bloomberg reports, and the NLRB does not have the power to evaluate punitive damages or hold executives personally responsible for labor violations.