California sues Tesla, saying the company permitted racial discrimination at its factory.

A California state agency is suing Tesla, accusing it of allowing racial discrimination and harassment to flourish at its San Francisco Bay Area factory in a lawsuit that was made public on Thursday.

The California Department of Fair Employment and Housing said that it had received complaints from hundreds of Tesla workers who reported being subjected to racist graffiti and widespread use of racial slurs, including from supervisors. They also accused the company of discriminatory practices. The agency said Black employees were assigned more physically arduous work and denied transfers and promotions more often than other workers.

“After receiving hundreds of complaints from workers, D.F.E.H. found evidence that Tesla’s Fremont factory is a racially segregated workplace where Black workers are subjected to racial slurs and discriminated against in job assignments, discipline, pay, and promotion creating a hostile work environment,” Kevin Kish, the department’s director, said in a statement. “The facts of this case speak for themselves.”

In a statement posted online on Wednesday, before the lawsuit was filed, Tesla said it “strongly opposes” all forms of discrimination and harassment. The company dismissed the lawsuit, arguing that the state agency had investigated dozens of previous claims in recent years and found no misconduct.

“It therefore strains credibility for the agency to now allege, after a three-year investigation, that systematic racial discrimination and harassment somehow existed at Tesla,” the company said. “A narrative spun by the D.F.E.H. and a handful of plaintiff firms to generate publicity is not factual proof.”

Tesla did not respond to a request for comment.

Tesla said that its Fremont factory has a “majority-minority work force” and described the lawsuit as counterproductive “at a time when manufacturing jobs are leaving California.” The company moved its headquarters to Texas last year and opened a new factory in the Austin area.

Tesla also said that the California agency had declined its requests for information on the accusations. The company plans to ask the court to “pause the case and take other steps to ensure that facts and evidence will be heard,” it added.

The lawsuit comes a few months after a federal jury in San Francisco awarded $137 million to a Black former Tesla employee who said he had faced racial harassment from a supervisor and other colleagues while working at the Fremont factory in 2015 and 2016. Employees had drawn swastikas and scratched a racial epithet in a bathroom stall and left drawings of derogatory caricatures of Black children around the factory, he said.

The following month, Jessica Barraza, another Tesla employee, sued the company, accusing it of allowing pervasive sexual harassment, both verbal and physical. Six more women sued the company in December, citing similar treatment.

Last month, one of Tesla’s top Black executives, Valerie Capers Workman, left the company. As head of human resources at Tesla, Ms. Workman was often the face of its response to such suits.