Dozens of Black employees at Tesla’s flagship factory in California have alleged that they faced racist slurs, unequal pay and promotion opportunities, as well as bullying by supervisors on a daily basis, while management failed to adequately address their complaints.

The allegations form the basis of a lawsuit filed against the Elon Musk-owned electric vehicle maker by the state of California, United States with the trial beginning on Monday with opening arguments.

Brett Watson, a lawyer for California’s Civil Rights Department, presented the court with photographs taken inside Tesla’s Fremont factory.

The images showed the N-word scratched onto a grey-blue metal surface and written in black marker on a wall.

Court documents also cited instances of “KKK”, swastikas, the Confederate flag, a white supremacist symbol and the phrase “go back to Africa” being scrawled in bathrooms, lockers, workplace benches and lunch tables.

Watson also detailed several racial slurs that workers said had been directed at them personally. In one reported incident, a Black employee said he was asked: “You want to hang from a tree?”

“Despite what Tesla might argue, you will hear Black workers were deeply offended,” Watson said. “These experiences cannot be dismissed as a few bad apples … hundreds of complaints to Tesla and [the Civil Rights Department] will show these experiences were not isolated.”

Watson said Black employees at Tesla were subjected to “rampant racism” that remained unchecked for years.

He said workers referred to the factory as a “slaveship”, “the plantation” and “The Elon Slave Labor Association”, using the initials TESLA.

According to Watson, one Black employee told state lawyers that he heard racial slurs between 50 and 100 times a day.

The lawsuit, filed against Tesla in February 2022, accuses the company of violating California’s Fair Employment and Housing Act by failing to address racial discrimination at the factory.

The state alleges that the Fremont plant was racially segregated, with Black employees earning lower wages, receiving fewer promotions and being terminated more frequently than their white colleagues.