At least 11 people were injured in a gas line explosion in the central California city of Fresno, media reported.
The explosion occurred at the Fresno County Sheriff's gun range on Friday, a county official said.
He said a work crew which included county jail inmates using heavy equipment hit a Pacific Gas & Electric Co. pipe carrying natural gas, CBS News reported.
Witnesses reported seeing a large fireball shooting about 200 feet into the air, a Fresno Fire Department official said.
An investigation has been launched into the incident.