57 Bug Bombs Set Off Blast at Santa Ana Home : Pesticides: Facility for developmentally disabled was fumigating for roaches. A pilot light touched off the explosion, which caused $125,000 in damage. No one was hurt.

An arsenal of bug bombs did more than kill the roaches Monday at a home for the developmentally disabled. It touched off an explosion that raised part of the roof, dislocated two walls and shattered windows in the four-bedroom house, authorities said.

Investigators blamed a combustible mix of more than 50 bug bombs that detonated near a pilot light from a gas stove.

“They were fumigating for bugs and they kind of overdid it,” said Karl Feierabend, a Santa Ana Fire Department spokesman. “It could have been worse.”

No one was injured in the 9:30 a.m. blast, which was heard throughout the 600 block of South Townsend Street. “The explosion was so rapid that there wasn’t enough time for a fire to ignite,” Feierabend said.

The explosion caused an estimated $125,000 in damage, causing a back wall to swing open “like a door” about 10 feet from the house, and scattering shards of glass inside and outside the home, Feierabend said. The roof “lifted and set down again,” he said.

The house was empty when the blast occurred. The owner declined to comment Monday as a team of firefighters used giant fans to air out the house and assembled rows of spent bug bombs on the front patio.

Three developmentally disabled adults are currently placed at the home, although one was in the hospital Monday when the incident occurred, said Diane Hawthorne, licensing program supervisor with the state Community Care Licensing office, which monitors group homes.

Monday morning, two of the residents stood outside the home among piles of clothes and other belongings that had been removed in preparation for the bug fumigation. They were moved to a another home later in the day, Hawthorne said.

Feierabend said there was a roach infestation in the home from a large amount of food accumulated over the past few months.

At least 57 “Max” and “Hot Shots” pesticide bombs were set off Monday morning to rid the 1,300-square-foot structure of bugs, authorities said. Each fumigant canister typically covers from 200 to 500 square feet, Feierabend said.

Steve Hill, deputy agricultural commissioner for Orange County, said the explosion could have been prevented if the occupants had followed instructions on the canisters.