Answers Still Elusive In San Bruno Pipeline Blast

toggle caption Luis Alvarez/AP

Federal investigators are still piecing together what happened minutes before last month's massive natural gas explosion in San Bruno, Calif.

In a preliminary report from the National Transportation Safety Board, investigators say a power failure led to a brief change in pipeline pressure. But the report does not say the pressure change caused the blast that killed eight people and destroyed 37 homes.

Many survivors are still reliving that horrible night in the San Francisco suburb.

As victims of the San Bruno disaster go, Kevin Ashley's family is among the fortunate. While some families are in motels or staying with friends, the Ashleys found a comfortable home in a quiet subdivision.

Still, Ashley, a father of two young children, is visibly uncomfortable as he recalls the explosion that rocked his house.

"It was a nice Thursday day. I remember the goldness and the yellowness of the sun and the beauty of the day and then all of a sudden it changed in a matter of seconds from the rumble of the ground to the sky turning black and me grabbing both my kids, trying to figure out what's going on -- if it's a plane crash," he remembers. "It's running through my mind, I hope my kids don't die."

Running out of his house, Ashley's year-old daughter banged her head on a doorjamb, opening a big gash.

"And as I looked down the street a wall of fire, a big orange ball was coming towards us and I just grabbed the kids and fled and ran," Ashley says.

Remarkably, Ashley's home, which is across the street from the ruptured pipeline, survived the explosion and fire. But everything inside is smoke-damaged and trashed.

And then there are their psychological scars. Ashley and his wife, Michele, talk about lingering bouts of anxiety. They have just returned from a victims support group. "The reason why we went to the support group was because I thought maybe moving into a new home would help some of my feelings or help me feel better, but there's not a moment that I am still not thinking about it," Michele says.

Figuring Out What Happened

The Ashleys aren't the only ones preoccupied with the pipeline explosion. "Customers are asking what went wrong here and is it going to happen again?" says Mindy Spatt, a spokeswoman for a utility industry watchdog group called TURN. She recalls that the pipeline's owner, Pacific Gas & Electric, has said that it had inspected the San Bruno line and found no problems.

"So the fact that they inspected it simply raises more questions. What kind of inspection was done? Were best practices followed? Were inspectors properly trained?" Spatt says.

Those were the same questions raised by federal investigators when a gas pipeline exploded in Rancho Cordova, Calif., back in 2008. It killed one person and injured five others. Like the San Bruno explosion, this one also involved a PG&E pipeline. At the time, federal investigators criticized PG&E for failing to adequately check the gas leak.

In San Bruno, investigators are looking at everything from problems in the pipeline control room to maintenance of the transmission line. Robert Bea, a professor of civil engineering at the University of California, Berkeley, says he'd look at the topography of the San Bruno neighborhood.

"You could see that this pipeline was at the bottom of a hill. And as I looked at that, I said 'Uh-huh, water likes to run downhill.' And so I probably got the steel and those welds in contact with water," Bea says.

Bea says that might mean corrosion weakened the pipeline.

'It Shouldn't Happen Anywhere'

For its part, PG&E this week announced a plan to regain public confidence in its safety program. It will replace several hundred manually operated shutoff valves with automatic or remote-controlled systems. In last month's disaster, it took nearly two hours for workers to manually shut off the gas after the explosion.

PG&E President Chris Johns says an accident like the one that happened in San Bruno "should never happen."

"It shouldn't happen here. It shouldn't happen anywhere," Johns says.

Johns would get no argument from Michele Ashley. "Just because the fire is no longer in the news doesn't mean the neighborhood and my family is not living that night and still living it out every day," she says.

This week the California Public Utilities Commission will announce the formation of an independent panel to investigate the incident. The results of a detailed report by the NTSB are months away.