Three workers suffered burns Wednesday in an accident at luxury electric carmaker Tesla's plant in California, managers said, in the latest blow for the US company.

One victim was seriously injured when a low-pressure aluminum casting press failed at the plant in Fremont, 40 miles (64 km) southeast of San Francisco, said Tesla, among the world's most valuable car companies.

"Two sound relatively minor, one more serious," Tesla chief executive Elon Musk told the San Jose Mercury, saying he would visit them in hospital, and "will personally ensure that they receive the best possible care."

The three injured were taken to hospital with second-degree burns, the newspaper reported.

A company statement, cited by the San Francisco Chronicle, said: "There was a failure in a low-pressure aluminum casting press .. Three employees were injured by hot metal from that press."

The Fremont Fire Department said on its Twitter feed: "Tesla incident involved pressurized equipment. No fire, no explosion. 3 treated and transported for burns."

Tesla, which makes a $75,000 sedan in heavy demand from well-heeled buyers, saw shares run up 470 percent from January to a record $194.50 earlier this year.

That climb put Tesla -- founded in 2003 by Musk, a co-founder of PayPal and SpaceX -- among the world's most valuable car companies despite expectations it will sell around 21,000 autos this year.

But its shares sank in October after a fire in a Tesla luxury sedan. A widely seen video showed a Model S, Tesla's $75,000 marquee model, up in flames on a street near Seattle, Washington.

They also skidded lower earlier this month after a disappointing earnings report.