The National Transportation Safety Board is investigating the length of time it took Pacific Gas and Electric to shut off the gas after an explosion and three-alarm fire in San Francisco’s Inner Richmond neighborhood Wednesday caused by a gas pipeline breach.
At a press briefing Friday, NTSB board member Jennifer Homendy said the federal agency has inspected the site of the gas line rupture and the seven manual valves that PG&E crews accessed during the incident, and secured a section of pipe for further inspection. Investigators are now working to develop a timeline of events, conduct interviews and visit the pipeline control center.
PG&E took more than two hours to shut down the flow of gas during the fire, which broke out around 1:18 p.m. in front of 3300 Geary Boulevard after a fiber optics contractor working for Verizon struck a pipeline. The fire, which was not contained until shortly after 4 p.m., ultimately damaged four buildings, displacing several businesses and the residents of up to seven units.
“One area that we are still interested in is the length of time that it took to shut off the gas,” Homendy said.
PG&E officials have defended the time it took to shut off the gas, saying they needed to work slowly and carefully to avoid damaging other utility lines in the area. Further slowing the work is a state law requiring them to dig by hand if they know there is a gas line within 24 inches below the asphalt.
“This is a complex situation, beneath us is a complex web of utilities,” spokesman Blair Jones said Wednesday. “It’s not as simple as just digging right in and isolating a valve or pinching off gas, you have to go slow.”