A massive blast triggered by a suspected gas leak killed at least four people and destroyed more than 50 houses in a neighbourhood near San Francisco today.
The explosion was heard for miles and shot a fireball more than 1,000 feet in the air, sending frightened residents fleeing for safety and rushing to get belongings out of burning homes, witnesses said.
Fire crews flooded the ruins of burning homes with water.
Utility officials said a natural gas line ruptured nearby.
The blast left a giant crater and sent flames tearing across several suburban blocks in San Bruno just after 6pm.
Coroner Michelle Rippy said officials at the scene confirmed at least four deaths. At least 20 others were injured, some with critical burns.
Authorities said there could be other casualties but the fire and darkness blocked them from checking.
After the initial blast, flames reached as high as 100 feet as the fire leaving some homes in total ruins and reducing parked cars to burned out hulks. At least 120 homes also suffered serious damage.
The fire had spread to 10 acres and was 50% contained later, said an official.
California Lieutenant Governor Abel Maldonado, acting governor while Gov. Arnold Schwarzenegger was in Asia on a trade mission, declared a state of emergency in San Mateo County.
“It was like a bomb went off,” Maldonado told CNN from the scene early today.
He said the cause of the conflagration was still unclear.
Pacific Gas and Electric Co said a damaged section of a 30-inch steel gas pipeline had been isolated and gas flow had been stopped.
The National Transportation Safety Board sent a team to investigate.
Fire Capt. Charlie Barringer said the neighbourhood was engulfed by the time firefighters arrived, even though the fire station was only a few blocks away. He said the blast took out the entire water system, forcing firefighters to pump water from more than two miles away.
Victims suffering from serious burns began arriving at San Francisco Bay area hospitals shortly after the blast.