Explosion Kills 1, Injures 5 at Restaurant : Disaster: Powerful blast takes place shortly before the popular business was to open for Sunday brunch. The cause is not known.

Less than a half-hour before customers were expected for Sunday brunch, a blast ripped out a corner of a popular Southwestern-style restaurant, killing a bartender and injuring five others.

The 9:35 a.m. blast at El Torito Grill, in the upscale, red-tile-roofed Fashion Island shopping center, collapsed two walls and part of the roof and turned the kitchen and grill area into an enormous pile of stucco, wires and wood. It shook nearby buildings and pitched hunks of concrete into a hotel parking lot across the street.

Police were investigating the cause.

The bartender was killed and five employees--two busboys, a waiter, a bookkeeper and a cook--suffered minor to moderate injuries, officials said, ranging from scrapes to broken bones. All but one had been treated at hospitals and released by late Sunday. Newport Beach firefighter Gary Gunderson suffered heat exhaustion.

Authorities identified the dead bartender as Antonio De Santiago, 36, of Fullerton. He was the father of three.

About 25 employees were inside preparing to open for brunch at 10 a.m. when the explosion occurred, said Newport Beach Fire Department Battalion Chief Ron Sutherland.

“We’re lucky it was 9:30 and not 12:30, when we would have had a lot of people in there,” Sutherland said.

Jose Macias, a cook from Costa Mesa, said: “A big pot of black beans hit the cook in the back. Things were going everywhere.”

“It was such a strong blast, I thought it was an earthquake,” said a dazed cook, Ezekiel Casillas of Costa Mesa, as he looked at the crumbled building. “I just threw myself on the floor.”

Waiter Juan Betular said pipes broke, water gushed through the restaurant and “ceiling material fell all over the place. There was a crack in the bar and liquor bottles fell out.”

Busboy Pedro Gutierrez, 41, of Newport Beach, who was treated for a bruise and gash on his leg, said that the force of the blast threw him across a room. Temporarily blinded by the steam and smoke, he crawled toward a hole in the rubble.

Employees reported that they did not smell gas until after the explosion, which led fire officials to believe that an underground gas leak was to blame. If a leak had occurred above ground, Sutherland said, people on the premises probably would have smelled gas before the explosion.

But Bob Perry, district manager for Southern California Gas Co., said workers dug under the street near the restaurant, cut off gas to the line that serves the restaurant and conducted pressure tests on it. No leak was found, ruling out an underground gas leak as the cause of the blast, Perry said.

Jose Nieto, a food service worker, said he was outside the restaurant when the explosion occurred. He ran in to pull people out, but the spraying water, dust and falling debris forced him to leave.

“I went in and the smell of gas was pretty bad,” Nieto said.

Across the street, where disheveled employees gathered after escaping the blast, executive general manager Marshall G. Wade Jr. told them the company would try to find jobs for the 150 workers at other El Torito restaurants or pay them for four to five weeks, while the restaurant is closed.

Evelyn Hellwig of San Diego, who was staying at the Newport Beach Marriott Hotel and Tennis Club across the street, said the blast shook windows and set off alarms. “I thought we might have to get evacuated,” she said.

Times staff writer Gebe Martinez contributed to this story.