Tesla has been sued by the U.S. Equal Employment Opportunity Commission for alleged race-based harassment and retaliation for treatment of black workers at its Fremont, Calif., manufacturing plant.

The federal agency says the electric-vehicle maker tolerated “widespread and ongoing” harassment of black workers and subjected some to retaliation for opposing the treatment.

It says a pattern of regular harassment stretched from 2015 to the present and included pervasive stereotyping, hostility and slurs, sometimes in the form of graffiti, including on new vehicles as they left the production line.

The EEOC says workers who objected to the treatment endured retaliation, including firing, job duty changes, transfers and other actions.

It said an attempt to reach a settlement was unsuccessful. It filed the lawsuit, seeking compensatory and punitive damages and back pay for affected workers, plus injunctive relief aimed at reforming Tesla’s employment practices to prevent discrimination.

“Today’s lawsuit makes clear that no company is above the law, and the EEOC will vigorously enforce federal civil rights protections to help ensure American workplaces are free from unlawful harassment and retaliation,” said EEOC Chairman Charlotte Burrows in a statement about the lawsuit.

The suit follows a California state lawsuit last year on similar claims. Tesla has said it opposes discrimination and addresses workers’ complaints.

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