A fire on the grounds of Tesla Inc.'s car factory in California on Thursday burned a scrap pile and sent plumes of smoke into the sky but was extinguished before it could cause major damage. Tesla said the fire wasn't near the outdoor tent it erected this year to expand vehicle assembly as it raced to increase output of its Model 3 sedan, and the company said the fire won't affect production. Chief Executive Elon Musk said it started in a pile of cardboard being prepped for recycling, and he praised the rapid response of local firefighters. "No injuries or damage to factory," said a post on his Twitter account. It was the latest of several fires over the past year in or outside the Tesla factory in Fremont, Calif., and resembled one two months ago that Tesla said at the time had hit a structure housing cardboard and recyclable material outside the factory. Tesla and the Fremont Fire Dept. said they are investigating the cause of the latest blaze. The incident came at a sensitive time for Tesla, after Mr. Musk shocked investors and observers earlier this month with a tweet saying he wanted to take the Silicon Valley car maker private at a price that would value it above $70 billion. U.S. securities regulators are investigating Mr. Musk's disclosure about the plan and his claim to have secured funding for a deal, which his subsequent comments showed wasn't accurate. Mr. Musk has hired advisers but has yet to make public any formal proposal.