The 46-year-old Asian man set fire to himself in Creative Nails & Spa shortly after noon, Costa Mesa police said. He suffered third-degree burns, police Sgt. Clint Dieball said.
A man inside the salon used a fire extinguisher to put out the flames, Dieball said. No one else was injured and the salon sustained minor fire damage.
Investigators have not determined a motive, but police said the man's estranged wife was working in the salon.
Sherry Skipper-Spurgeon, a longtime customer at the salon, said she was having her nails done by the store's manager when the manager's husband, with whom she has three children, came in appearing "very distraught" and began shouting at her in Vietnamese.
"He had a bucket with him, and he takes the bucket and pours this whatever liquid over the top of his head," Skipper-Spurgeon told the Orange County Register. "Then you could smell it, like gasoline."
The manager, whom she knew only as Lina, told the other employees and the three customers inside the store to step outside and her husband sat down on the floor, said Skipper-Spurgeon, who dialed 911.
"Next thing you know, someone says 'He's got a lighter!'" Skipper-Spurgeon said.
The manager's father and brother had been in the back of the store doing repairs and rushed out, the brother blasting the flaming man with a fire extinguisher as customers ran back in and used towels to help smother the flames.
Skipper-Spurgeon said the wife sobbed in her arms for about an hour after her husband was taken away.
"This is absolutely devastating for her," she said. "She didn't know how she was going to tell her kids about this."
Information from: The Orange County Register, http://www.ocregister.com