Three former Tesla factory workers have filed a lawsuit against the company, claiming they were subject to constant racial discrimination and harassment in the electric car company's factories. "The men, who are African-American, claim in a new complaint filed Monday in state court that Tesla supervisors and workers used racial epithets and drew racist graffiti on cardboard boxes," reports The Mercury News. From the report: The new suit is the second by black employees charging Tesla failed to address racial antagonism at its factory. The electric vehicle maker also has a hearing before the National Labor Relations Board over claims it illegally tried to silence workers promoting a union. The complaints come as the Tesla heads into a crucial ramp-up of Model 3 production, its lower-cost electric vehicle. A Tesla spokesman denied the suit's allegations and said the men never raised the complaints to the company during their brief time at the plant. "Given our size, we recognize that unfortunately at times there will be cases of harassment or discrimination in corners of the company," the spokesman said. "From what we know so far, this does not seem to be such a case." The suit, filed in Alameda County Superior Court, claims Owen Diaz and his son, Demetric, were called the N-word while they worked at the Fremont factory, and supervisors did little to stop it. A third man, Lamar Patterson, also claims he was subjected to insensitive racist remarks.