Deadly gas explosion is focus of NTSB hearing

A top federal safety official is promising to take "every step possible" to prevent another gas pipeline explosion like the one in San Bruno, California, last September that killed eight people.

National Transportation Safety Board Chairman Deborah Hersman opened a special three-day hearing on the San Bruno accident on Tuesday. She acknowledged the pipeline rupture that sent a giant pillar of fire into the air and left dozens of homes in the suburban San Francisco neighborhood in fiery ruins has caused investigators to question whether the same thing could happen elsewhere.

Eight Pacific Gas and Electric Co. officials are scheduled to testify.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

Officials for a California gas company are facing questions about decisions they made prior to a pipeline explosion in September that killed eight people, injured many more and left dozens of homes in smoking ruins.

The fact-finding hearing Tuesday is part of an investigation by the National Transportation Safety Board that has already raised questions about whether Pacific Gas and Electric Co. officials should have known they were putting public safety at risk. Eight PG&E officials are scheduled to testify.

The 1950s-era transmission line that ruptured underneath a San Bruno, Calif., neighborhood had bad welds, according to NTSB metallurgists. PG&E officials have acknowledged they spiked pressure in the line beyond its federal safety limits at least twice. Investigators have identified a flawed seam weld on the line as the starting point of the deadly rupture.

Federal officials have said regulations require operators to inspect welds after pressures spikes for damage that could cause a rupture. It's probable that the problem welds would have been discovered if the company had used rigorous testing methods, safety experts have said.

Instead, PG&E conducted a less time-consuming, less-expensive test in 2009 that wasn't suited for finding problem welds, safety experts have said. PG&E records inaccurately identified the pipe as not having a welded seam.

The line also was not equipped with remotely operated or automatic shut-off valves that would have halted the gas within minutes of the accident - devices the safety board has recommended to industry and regulators for decades. A giant pillar of flame continued to be fed by gas for 89 minutes after the San Bruno explosion before it was finally shut off.

Last fall, after the explosion, PG&E announced it would install more remotely operated and automatic valves in highly populated zones - urban areas with at least 50,000 people and at least 1,000 people per square mile.

Coroner's reports indicate at least five of the people killed in San Bruno were trying to flee when they died.