Gas Blamed in San Francisco Building Blast

Gas caused the mysterious explosion that leveled a Tenderloin district building and left three dead, authorities said, but they still cannot explain how the blast occurred.

Fire officials and Bureau of Alcohol, Tobacco and Firearms investigators do not yet know the type of gas involved or the sequence of events that led to the explosion, according to a statement released Monday by Fire Chief Joseph Medina.

The building at Post and Hyde streets in downtown San Francisco was reduced to rubble in the explosion and fire Thursday night. A dry-cleaning business across the street was damaged and windows in surrounding buildings were broken.

Investigators do not believe the explosion was caused by a natural gas leak from the street, or in the pipes within the building. But it is possible that gas leaked out of a furnace or water heater and built up until it was ignited.

“So far our investigation shows there were no problems in our system coming from the street,” said Lyle LaFaver, spokesman for Pacific Gas & Electric. “If it was an appliance that was involved, that’s on the customer’s side of the meter. We don’t maintain appliances.”

LaFaver did not know what appliances were in the building but said typical household appliances that run on gas include stoves, water heaters and wall heaters.

Bureau of Alchol, Tobacco and Firearms spokesman Ed Gleba said earlier Monday that natural gas had not been ruled out as a cause of the explosion. Investigators had previously eliminated the possibility of a bomb or other incendiary devices.

Meanwhile, a chemical analysis of the debris was under way.

The three men found dead on the sidewalk near the building were identified as Armando Gonzalez and Adalberto Flores-Diaz of San Francisco and Adolpho Salinas of Atlanta.