The California Public Utilities Commission had a team in Fresno to investigate the cause of a spectacular gas line explosion that left 14 people hurt on Friday.
Witnesses described a scene of destruction in the aftermath, with a crater marking the point of the explosion at a Fresno County sheriff's gun range.
The blast occurred behind the range about 2:30 p.m. when a county worker leading a team of jail inmates building a dirt road accidentally struck the gas line, said Fresno Fire Department spokesman Pete Martinez.
Thirty-five firefighters quickly subdued the blaze, and Pacific Gas & Electric cut off the gas supply to the line, Martinez said.
The county worker leading the team and at least one of the inmates were critically injured in the explosion, which sent a fireball 100 feet into the sky, authorities said. The inmates were part of a work program at the Fresno County Jail, Martinez said.
"I heard a whirring sound like a helicopter, then two booms and fire," said Mark Price, who witnessed the blast.
Spencer Olson was drilling for water nearby.
"My jaw dropped," he said. "I saw an enormous fireball."
The accident forced the closure of Highway 99 in both directions for several hours, Martinez said.
Investigators were still working Friday evening to identify what ignited the blaze.
Martinez said the investigation was hindered by the large crater with heavy equipment demolished in the fire. Investigators were unable to speak with the work team leader.
Fresno County Supervisor Henry R. Perea told the Fresno Bee that burns covered more than 30% of the man's body, including his torso, legs, arms and hands.
"He is pretty lucky," Perea told the newspaper. "As the gas line was exploding, he was jumping off the equipment, so he kind of saved himself by acting quickly."