Gas Blamed for Blast That Razed Mansion : Thousand Oaks: An investigator says the cause was a leaky fireplace. Firefighters had been summoned to the house a year ago to check a propane problem.

A smoke-blackened safe the size of a two-drawer file cabinet sat on the curb Wednesday, a yellowed deed atop it, the safe’s lock melted from the heat of an explosion that destroyed a sprawling mansion in the hills outside Thousand Oaks.

The house’s owner, whom authorities identified as flight attendant Michelene P. Zumbrun, was traveling when the blast of fire blew through the house on Colt Lane late Tuesday, shattering windows across the street. The explosion is believed to have been caused by a leaky gas line, authorities said.

On Wednesday, fire engines blocked the street as firefighters knocked over the few remaining walls of the house, soaking the last hot spots of the hillside property situated on a steep, winding street with a sweeping view of the Ventura Freeway.

Lisa Moxley, who rents a room inside the house, suffered cuts to her hands while climbing out a window to escape the house, authorities said. Moxley was the only person inside when the blast shook the neighborhood at 8:06 p.m.

A woman who said she was a resident of the house and Zumbrun’s granddaughter said her Belgian sheep dog, Tender, was burned in the blaze before being rescued by a neighbor.

“We tried calling the dog and he wouldn’t come out,” said the woman, who declined to give her name. “Then the guy just jumped in there and got him.”

The neighbor, Bruce Beckwith, said he rescued the dog because he was afraid the granddaughter would go in after her in the minutes before firefighters arrived at the scene.

“We could see the dog,” he said. “The room was burning. I had to go over the bed and around the dresser. The dog was actually burning. Its fur was burning.”

The dog was being treated Wednesday at an animal hospital.

County Fire Investigator David Chovanec said the two-alarm fire was caused by a leaky gas fireplace. The propane filled the house’s foundation, then was likely sparked by the refrigerator, Chovanec said.

“There’s pieces of the refrigerator 20, 30 feet in the back yard,” Chovanec said.

Another neighbor, Neil H. Fisher, said, “It was like a bomb going off in the front yard.”

Chovanec said the house, last assessed at $452,789, was a total loss.

County Fire Capt. Loyd C. Wood said firefighters had been summoned to investigate a propane leak at the white stucco house a year ago.

On Wednesday, a handful of family members worked to salvage what they could, packing up thick leather-bound books and pictures and refusing to identify themselves other than by their relationship to Zumbrun.

One man, who told firefighters in a thick accent that he was Zumbrun’s son-in-law, warned onlookers to stay behind emergency barricades.

Peggy Clifford, who lives nearby, said she was angry at Zumbrun because the fire put the other houses in the canyon in jeopardy.

“It was a good thing the wind was calm, because it would have taken the neighborhood,” Clifford said. She said Zumbrun expanded what was originally a small ranch house built in 1967 into a four-bedroom mansion firefighters said was 8,000 square feet.

Dale Town, district supervisor for the county building and safety department, said there was no record of code violations at the house, and Zumbrun had obtained the proper permits to add a kitchen, three-car garage, tack room, living room and laundry room to the structure.

Clifford said Zumbrun invested a lot of money in decorating the house.

“They had a lot of beautiful things,” Clifford said.

On Wednesday, though, the beautiful things were gone and the charred metal safe was all that remained intact.