A preliminary investigation by a state utility agency revealed Fresno County workers who hit a gas line, triggering an explosion that injured 14, had not checked for underground utilities before work began, officials said.
The California Public Utilities Commission said Monday it appears no one had called the agency's hotline to check for underground utilities ahead of digging Friday afternoon near a Sheriff's Office gun range.
A county worker leading a team of jail inmates building a dirt road accidentally struck a gas line about 2:30 p.m. Friday, sparking an explosion that sent flames more than 100 feet into the air and injuring 14 people, two critically.
Witnesses described a scene of destruction in the aftermath, with a crater marking the point of the explosion at the gun range.
Thirty-five firefighters quickly put the blaze down, and Pacific Gas & Electric cut off the gas supply to the line, Fresno Fire Department spokesman Pete Martinez said.
PUC investigators will review PG&E's utility maps, assess the company's response to the blast and determine who ultimately is culpable for the incident.
The county worker leading the team and at least one of the inmates were critically injured in the explosion. 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 California 99 in both directions for several hours, Martinez said.
Investigators were still working Friday evening to identify the cause of 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."