State lawmakers meeting in the San Francisco suburb where eight people were killed in a natural gas explosion grilled the head of the California Public Utilities Commission Tuesday evening over what they characterized as years of lax oversight of the ruptured pipeline's operator, Pacific Gas & Electric.

Assemblyman Jerry Hill, who represents the city of San Bruno, organized the town hall meeting so his colleagues and residents of the community where 38 homes were destroyed and 55 families remain displaced could get an update on what PG&E and state regulators were doing to prevent a repeat of the Sept. 9 disaster.

"It is not business as usual you are getting," CPUC executive director Paul Clanon said at the start of the gathering, noting that two of the people killed in the blast were a commission employee and her 13-year-old daughter. "We are doing a professional job, but it's personal."

Clanon tried to defuse one of the fiercest criticisms since the explosion sent a 2,000-degree fireball through a neighborhood unaware that the high-pressure gasline ran under its streets — that PG&E called the pipe "high-risk" in 2007, received permission from the commission to bill ratepayers to upgrade it and then dropped the improvements the next year.

"What it may represent, and that's a question for PG&E, is they went out and got more information about that pipeline and decided that based on their own view of pipeline safety it was better to go back and work on another stretch of pipeline and then to go back to this one," he explained.

Residents in the audience of about 100 people interrupted to ask what had happened to the $5 million the utility had supposedly set aside to work on their pipeline. Clanon said he assumed it had gone "to other pipeline maintenance" but conceded he did not know for sure.

His explanation drew a sharp rebuke from Assemblyman Tom Ammiano, D-San Francisco, who chairs the Assembly Public Safety Committee.

"You are very, very glib," Ammiano said. "I've heard you worm out of the question around the $5 million free Monty twice now, and I'm somewhat distressed by the spin you are trying to put on it. I would suggest you try to re-examine your answer."

Kirk Johnson, PG&E's vice president for gas engineering and operations, told the gathering he could not comment on the cause of the pipeline's rupture because the National Transportation Safety Board is investigating. The board's final report is likely more than a year away, he said.

Johnson said the company was not waiting for the NTSB report to modernize its pipeline infrastructure, install new pipeline shut-off valves and rethink its inspection practices.

"PG&E is determined to learn from the San Bruno accident," he said.

The utility has set aside $100 million to compensate San Bruno and its city government. Along with paying for repairs not covered by insurance, the money will be used to help residents who do not return to the incinerated neighborhood relocate without losing their home equity, Johnson said.

A trio of professional experts also addressed the meeting and said they had doubts about whether PG&E was using the best available technology for inspecting its pipelines.

"The rupture raises serious questions about the operator and regulatory management in California," said Rick Kuprewicz, president of Accufacts, a consulting company that specializes on pipeline operations and design in heavily populated areas.

Hill, D-San Mateo, introduced a bill on Monday that would require utilities to prioritize repairs to pipelines near earthquake fault lines and to install valves that could automatically seal off a ruptured line.

Among the issues the NTSB is investigating is why it took PG&E crews nearly 90 minutes to deploy manual valves to stop the flow of gas into San Bruno the night of the explosion.