Tesla may face a class-action lawsuit after 240 Black factory workers in California described rampant racism and discrimination at the electric automaker’s San Francisco Bay Area plant, including frequent use of racial slurs and references to the manufacturing site as a plantation or slave ship.

The testimonies filed Monday in Alameda County Superior Court comes from contractors and employees who worked on the production floor of the factory in Fremont, roughly 40 miles (65 kilometers) southeast of San Francisco. The vast majority worked at the site between 2016 to the present. Lawyers suing Tesla, Inc. estimate at least 6,000 workers could be part of the class.

The individual testimonies are part of a 2017 lawsuit brought by Marcus Vaughn, who complained in writing to human resources and to Tesla CEO Elon Musk of a hostile work environment in which he was called slurs by co-workers and supervisors. No investigation was conducted and he was fired for “not having a positive attitude,” according to his lawyers.

The lawsuit is just one of several lawsuits alleging racism, harassment and discrimination at the Fremont plant.

Last year, California regulators sued Tesla in state court, alleging the company turned “a blind eye” to abuses and that Musk told workers to be “thick-skinned” about racial harassment. In April, a federal jury awarded another former Tesla employee $3.2 million for racial abuse he suffered.

Bryan Schwartz, one of Vaughn’s lawyers, said the case has dragged on for years as Tesla sought to force the lawsuit into arbitration. Instead, the California Supreme Court in April allowed Black workers to seek a public injunction in court that would require Tesla to change its work environment.

“To have this scope of egregious harassment right here in Silicon Valley, it’s disgusting,” Schwartz said, adding that it’s shocking that “Tesla has allowed this kind of pervasive harassment to go on as long as it has.”

Attorneys for Tesla did not respond to emailed requests for comment.

All of the declarants said they heard use of one particular racial slur, with more than half saying they heard supervisors and managers use that word, according to a declaration summarizing the statements.

Dozens also said higher-ups direct the racial slur toward them, the summary stated, and nearly half said they experienced or saw other Black workers tasked with more physically laborious work and disciplined more frequently.

Production associate Albert Blakes said in his statement that it was difficult to go to work, knowing he would face racist slurs, references to slavery and offensive graffiti for 12 hours at a time. He said he made a verbal complaint to human resources in late 2021, but never heard back and nothing changed.