An electrical overload was identified yesterday as the cause of a March 28 explosion and fire that destroyed a home at 241 E. Walnut St. in Allentown.
And Fire Chief Ernest E. Toth and Deputy Chief Claude Kohl Jr., the department's head of investigations, said the "explosion" was the result of a "flashover."
They explained that the fire apparently was burning for some time and built up intense heat and carbon monoxide gas. "When some point in the building weakened admitting a rush of air, the flashover occurred," said Kohl. The blast occurred about 9 a.m.
The intensive investigation was delayed until this week so Zuk Demolition Co. crews could remove the rubble from the home. The three floors dropped onto each other as a result of the fire, making a search of the gutted structure unsafe.
Much of that rubble was removed earlier this week, permitting investigators to enter the structure and make a probe to determine the cause.
The investigation found that the overload occurred in wiring in the southwest corner of the first-floor family room, according to the fire officials.
Kohl said the insurance loss on the property amounts to $148,000.
Toth said the investigation confirmed his earlier suspicions that neither gas nor an oxygen tank caused the explosion.
The chief said, "Had it been a gas explosion, the entire home would have crumbled."
The property owner, Harlow E. Landstrom, used the oxygen tank because of his emphysema.
Toth said the only gas at the home was that used to supply a hot-water heater in the basement. "And there was very little fire in that area at all," the chief said.
He said investigators also found a small propane bottle used for a barbecue grill. "That was too small to cause a situation like we had there," he said.
Demolition crews have leveled the structure. All that remains to be cleared away is some debris that dropped into the basement as a result of tearing away the rest of the dwelling.
Landstrom is in the Lehigh Valley Hospital Center, where he was a patient when the explosion and fire occurred.