In response, the utility company sent its own workers to the scene to isolate the damaged line and stop the flow of gas.
Firefighters arrived on scene soon after the broken gas line was reported, around 7:50 a.m., but were cleared about five minutes later, according to the Alameda County Fire Department.
Over the next hour or so, PG&E crews identified two damaged areas releasing gas, Sarkissian said â one was stopped at 8:18 a.m. and the second was stopped at 9:25 a.m., but the explosion happened roughly 10 minutes later. Three of those injured were PG&E employees.
âPG&E will be conducting an extensive investigation around potential cause and will support other investigations that may take place,â Sarkissian said.
After the explosion triggered a three-alarm fire, 75 firefighters responded to the scene, said Hurd, the Fire Department spokesperson.
