According to San Jose Mercury News on May 19th:

PG&E says its natural gas pipeline system on the peninsula remains safe even though the utility found that its records for a pipe beneath East Palo Alto failed to match what was actually buried beneath the community.

The utility discovered the discrepancy in January when it excavated a portion of gas Line 101 in the East Palo Alto area.

PG&E’s records showed that the line had a wall thickness of 0.3125 inches, but it actually turned out to be 0.25 inches thick, or 20 percent thinner than recorded.

The section of pipeline was removed and replaced with a new state-of-the-art pipe in February.

Investigators have determined that a fatal gas explosion in September 2010 in San Bruno was triggered by PG&E’s shoddy maintenance and flawed record-keeping, along with lax oversight by the state Public Utilities Commission.

San Francisco-based PG&E has spent $2.8 billion to upgrade and improve its far-flung network of gas pipes in northern and central California.

“It’s something that concerns me to have the mismatch of the records,” said Nathaniel Skinner, program and project supervisor with the PUC’s Office of Ratepayer Advocates.

The pipe could have a different characteristic than what the records show, and it still might be unsafe,” Skinner said. “The pipe might have a higher probability of failure but wouldn’t necessarily be unsafe.”

Still, the revelation is unsettling for the PUC unit.

Anytime PG&E doesn’t know what’s in the ground, that raises red flags,” Skinner said.

PG&E says it will continue its work to pressure test gas pipelines, replace pipes and equipment, and install valves that can be shut off automatically and operated remotely in an emergency.