The nearly three hours it took Pacific Gas and Electric Co. to shut off the gas leak that caused an explosion at a Bernal Heights home was what troubled city supervisors most about the incident during a hearing Thursday.
The explosion blew out the garage and windows at 3987 Mission St. on Nov. 27, displacing the residents of four units in the building but injuring no one.
“The biggest concern to us, other than the well-being of our constituents that were impacted, was three hours was an unexceptable time to shut off the gas when there was a leak that caused an explosion,” said Supervisor Hillary Ronen, who represents the neighborhood on the Board of Supervisors.
Ronen called for the hearing before the Public Safety and Neighborhood Services Committee to investigate what transpired and hold PG&E accountable.
The explosion is the latest incident in San Francisco that has raised questions about PG&E’s infrastructure and emergency response. In April, a fire at a PG&E electrical substation knocked out power to a large swath of downtown San Francisco, reportedly costing The City $187,000.
“The explosion on Mission Street revives my concern about PG&E’s accountability,” Ronen said. “This incident opens the question of how we are regulating and overseeing PG&E.”
The company also has a tarnished reputation in the wake of the San Bruno pipeline explosion in 2010 and, more recently, for the alleged ties between PG&E transformers and the deadly October wildfires in the North Bay.
Supervisor Jeff Sheehy questioned whether the explosion indicates a larger issue with PG&E’s infrastructure that could lead to similar incidents elsewhere in San Francisco.
PG&E said the incident remains under investigation to determine the cause and whether widespread infrastructure improvements are needed.
Sheehy also questioned the response time to fix the leak.
“In a city like San Francisco that’s dense, prone to earthquakes, three hours of gas leaking is a challenge,” Sheehy said. “Going forward, if there’s a way to strengthen the system so that we don’t end up in a scenario where we have three hours of gas leaking, that would be good.”
Christine Cowsert, a senior director with PG&E, said a high concentration of gas in the area prevented utility workers from immediately capping the gas leak. Workers had to dig up Mission Street to plug the leak in a plastic offshoot of a six-inch steel main installed in 1992.
“It did take a little longer than typical, but not significantly extended,” Cowsert said.
Cowsert said PG&E has since offered cash assistance and temporary housing to the displaced and plans to assist with permanent housing.
San Francisco Fire Department Battalion Chief Rex Hale described the scene before the explosion. Firefighters witnessed water bubbling in the gutter along Mission Street and the heavy smell of gas, indicating a “significant” gas leak.
Hale said gas leaks are not uncommon with construction across San Francisco, but gas explosions are.
“PG&E had their work cut out for them on this one,” Hale said.
Cowsert said the investigation will be completed within one or two months.