Federal labor regulators allege that SpaceX illegally fired employees who publicly criticized Elon Musk, the exploration company’s founder and CEO.

According to allegations laid out in a complaint filed Wednesday by a regional office of the National Labor Relations Board, SpaceX wrongfully terminated eight employees and interrogated dozens more in 2022 after the workers wrote and shared an open letter calling for the company’s leadership to condemn Musk’s “disparaging” and “sexually charged” comments on social media.

The letter criticized SpaceX management for what the authors called the company’s failure to tackle a culture of “sexism, harassment and discrimination” within its workplace, the NLRB said in the complaint. Separately, they asked SpaceX to “condemn” Musk’s “harmful Twitter behavior.”