Records indicate the California Division of Occupational Safety and Health fined Tesla $2,700 last year for a serious violation at the Fremont factory that was uncovered during an accident investigation.
Cal-OSHA spokesman Peter Melton said investigators found a hydraulic power press did not have a proper stop control. At least one person was injured, but Melton did not know the extent of the injuries.
Tesla was also fined for an accident at a different Bay Area facility two years ago in which a worker lost a fingertip.
Two of the three workers injured when a machine malfunctioned at the factory on Wednesday remained hospitalized on Thursday. One suffered serious injuries, and the other two had minor injuries.
THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.
Three Tesla Motors workers are recovering from their injuries after a machine malfunctioned at the Bay Area car factory, spilling hot metal.
One employee was seriously hurt and two other sustained minor injuries when the low-pressure aluminum casting press spilled hot metal Wednesday shortly before noon, said Greg Siggins, a spokesman for the California Occupational Safety and Health Adminstration.
"Hot metal somehow burned the workers," said Siggins, who added that there was no fire inside the plant.
The most seriously injured Tesla worker received chest and upper-body burns, Cal-OSHA spokesman Peter Melton said. The three workers were taken to Santa Clara Valley Medical Center in San Jose with second-degree burns, Siggins said.
One of the workers was released Wednesday afternoon, hospital spokeswoman Joy Alexiou said. She could not disclose the workers' identities or conditions due to privacy laws.
Tesla CEO Elon Musk said in an email Wednesday that he planned "to visit them in the hospital later today and will personally ensure that they receive the best possible care."
The incident was being treated as an industrial accident, Siggins said.
"We will be talking to any witnesses, reviewing training documents and manuals to see if they are in accordance with specifications as part of finding out what happened," Siggins said.
Tesla Motors, which is headquartered in Palo Alto, makes its all-electric Model S sedan at the Fremont factory. Tesla took ownership of the former plant jointly-owned General Motors and Toyota four years ago and has transformed a portion of the cavernous auto plant into a state-of-the-art facility.
Wednesday's accident follows recent Tesla car fires in Washington state, Tennessee and Mexico that made headlines. Two Model S sedans caught fire after hitting a metal object in the road and a third caught fire after a high-speed chase.
None of the drivers were injured.
Musk said Tuesday that there are no plans for a recall and insisted the Model S is one of the safest cars on the road.