New Revelation Points to 1956 Pipe Test as Factor in Explosion

The San Francisco Chronicle has reported that there are new revelations from PG&E about what caused the 2010 San Bruno pipeline explosion.

In a filing to the California Public Utilities Commission on Tuesday, PG&E admitted for the first time that a high-pressure strength test conducted on Line 132 in 1956 caused a tear in a defective weld, and that over the course of 50 years the tear grew until it eventually ruptured.

The explosion left eight people dead, destroyed 38 homes and forever changed the makeup of the Crestmoor neighborhood.

While PG&E once again said it was "deeply sorry" for the disaster, the company said the new revelation comes from the recollection of a former employee who saw a pressure test being conducted on the pipeline around the time when it was installed.

"We have no records establishing where that pipe came from," the company said. "Nor do we have records showing a pre-service hydro test, although a former PG&E employee remembers one at about the location of the rupture."

PG&E made the filing in defense to accusations from the CPUC, which is for the deadline pipeline explosion.

The CPUC's Consumer Protection and Safety Division has blamed PG&E for failing to follow federal and state rules with its pipelines and for failing to properly monitor the maximum operating pressure of those lines.

According to PG&E's filing, the company maintains that it didn't knowingly flout pipeline rules because no law had yet been established to require high-pressure strength tests on gas transmission lines.

And while the former employee said he observed the 1956 strength test on a segment of Line 132, which was being installed between San Bruno Avenue and Sneath Lane during the development of the Crestmoor neighborhood, PG&E hasn't been able to locate any records confirming the test.

PG&E further claimed that state regulators' accusations of wrongdoing are "excessively broad" and create the false impression that PG&E is "an organization in which no one ever did anything right."

To see PG&E's full report filed with the CPUC on Tuesday, visit PG&E's regulatory cases page.

Follow us on Twitter | Like us on Facebook |Sign up for our daily newsletter |  Blog for us