Authorities said the home was so packed with homemade explosives that they had no choice but to burn it to the ground.
Remotely controlled explosive devices ignited the home in Escondido and it quickly became engulfed in flames as thick smoke rose high into the sky, going just as authorities had planned to avoid spreading toxic fumes through the community.
The fire began with puffs of smoke that rapidly grew larger and shot through the roof before spectacular orange flames overtook the house. Popping noises heard during the fire were likely hand grenades and ammunition, officials said.
At the height of the fire, Shirley Abernethy, 82, stood on a porch about 200 yards away.
"Oh my gosh! Look at those flames. They are as high as those trees. That's scary," Abernathy said.
The flames quickly ate away at the attached garage and then large chunks of the house. Within minutes the flaming framework was exposed and nearby shrubs were burning. A remote controlled fire sprinkler was activated.
Nearly all of the home was destroyed in about 30 minutes after a delay of nearly an hour as fire officials waited for an atmospheric condition known as an inversion layer to clear. The condition could have held the toxic smoke close to the ground.
"This has gone according to plan," said Jan Caldwell, a spokeswoman for the San Diego County Sheriff's Department. "They wanted to wait for that perfect moment."
Robert J. Kard, director of air pollution control for the county, said workers monitored for the blaze for dangerous pollutants and received no alarming reports.
The plume drifted toward the southeast as planned, over partially closed Interstate 15 and toward sparsely populated fields.
Meteorologists had been consulted to determine the most favorable conditions for the fire.
"It is a good day for a fire," said Caldwell, who described the plume as "very evil looking." " The fire will likely smolder for much of the day, said Caldwell. Residents were expected to be allowed to return by Thursday night.
Scores of nearby residents were evacuated earlier. Authorities used helicopters to monitor the burn.
Residents watched from outside the evacuation zone.
"Oh, how 'bout that!" Bruce McKeighan said as a pop was heard.
Crews had built a 16-foot firewall and covered it with fire resistant gel to protect the closest homes. They also closed a portion of a nearby interstate highway.
The house was rented by an out-of-work software consultant who authorities say assembled an astonishing quantity of bomb-making materials that included the kind of chemicals used by suicide bombers.
Earlier Thursday, police opened windows and doors at the home, and drilled holes in the roof. Authorities were given protective breathing masks in case they need to enter the house if the blaze got out of control.
Residents, onlookers and news crews were kept at least 400 yards from the home. A dozen curious people gathered at a nearby shopping center to watch the flames. Some people planned to climb atop their roof or seek other vantage points.
The fire was expected to reach about 1,800 degrees Fahrenheit -- hot enough to neutralize the unstable explosives inside.
Abernethy said burning down the home was best.
"They have no idea what is in there. There might be explosives in the walls and under things," she said. "Some people have crazy minds. You just never know who you are living next to."
Investigators say they are still trying to understand what motivated the renter, George Jakubec, to stockpile the material. Jakubec, 54, has pleaded not guilty to charges of making destructive devices and robbing three banks.
Bomb-squad experts determined the residence was too dangerous to go inside, so they drew up plans to burn it down. The home is so cluttered with unstable chemicals that even bomb-disposing robots couldn't be used to enter it.
Officers said they found the same types of chemicals used by suicide bombers and insurgents in Iraq and Afghanistan.
The materials included Pentaerythritol tetranitrate, or PETN, which was used in the 2001 airliner shoe-bombing attempt as well as airplane cargo bombs discovered last month by authorities.
Nearly every room was packed with piles of explosive material and items related to making homemade bombs, prosecutors said.
In the backyard, bomb technicians found six mason jars with highly unstable Hexamethylene triperoxide diamine, or HMDT, which can explode if stepped on. A coffee table was found cluttered with documents and strewn with detonators, prosecutors said.
The chemicals were found after a gardener accidentally set off an explosion at the home by stepping on what authorities believe was a byproduct of HMTD.
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Associated Press writer Elliot Spagat contributed to this report.
