Dozens of homes were destroyed in a massive fire on the peninsula.
California regulators launched a formal legal investigation Thursday into whether Pacific Gas & Electric Co. broke any laws in the deadly San Bruno pipeline explosion, a process that ultimately could lead to hefty fines and other penalties for the utility.
All five commissioners of the California Public Utilities Commission voted unanimously to open the penalty case after agency staff issued a scathing report saying the natural gas line blew up in part due to what they termed as the systematic failures of PG&E's corporate culture, which emphasized profits over safety.
The blast on Sept. 9, 2010, killed eight people, injured dozens and sparked a fireball that torched 38 homes in a quiet neighborhood overlooking San Francisco Bay.
Staff also cited the company's shoddy record-keeping and failure to follow federal pipeline safety laws and industry practices in their report, highlights of which were presented at the commission's public meeting.
"I pledge my very best effort to get to the bottom of this, and to impose very significant penalties on PG&E if staff's allegations of wrongdoing by PG&E are proven on the record,'' said Commissioner Mark Ferron. `"We owe this debt to the good people of San Bruno.''
An administrative law judge will hold a prehearing conference to set up a timetable for the case, which comes on the heels of two smaller legal probes.
PG&E President Chris Johns said the company will cooperate with the investigation.
"It is clear that PG&E's past gas operations practices were not what they should have been. We have admitted these shortcomings, and we are committed to raising the level of pipeline safety to new, higher standards,'' Johns said in a statement.
Last year, federal investigators from the National Transportation Safety Board who also looked into the blast found that a litany of failures by PG&E led to the explosion. They warned there was no certainty that those problems didn't exist elsewhere.
The board made a series of safety recommendations to regulators and the gas industry, concluding the accident wasn't the result of a simple mechanical failure, but was an "organizational accident.''