By Holly Quan

SAN BRUNO (KCBS) – The National Transportation Safety Board has issued its final accident investigation report into last year’s San Bruno natural gas pipeline explosion, placing most of the blame on Pacific Gas and Electric.

The report found that the probable cause of the accident was PG&E’s “inadequate quality assurance and quality control in 1956 during its Line 132 relocation project” and an “inadequate pipeline integrity management program, which failed to detect and repair or remove the defective pipe section.”

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A 30-inch diameter section of Line 132 ruptured on September 9, 2010, leading to a major fire that killed eight people and destroyed 38 homes in San Bruno’s Glenview neighborhood.

KCBS’ Holly Quan Reports:

The federal safety board found that the relocation project in 1956 allowed the installation of a substandard and poorly welded pipe section with a visible seam weld flaw that, over time, grew to a critical size, causing it to rupture with an increase in pressure.

That pressure increase stemmed from “poorly planned electrical work at the Milpitas Terminal.

Photo Gallery: San Bruno Explosion

The NTSB also laid blame on the California Public Utilities Commission and the U.S. Department of Transportation’s exemptions of existing pipelines from the regulatory requirement for pressure testing.

San Bruno Mayor Jim Ruane said he was glad to see that the report found that pipeline testing methods were inadequate.

“They had a direct assessment-type of a test where they put a stick in the ground and can tell whether a pipe has as rust or not. But it doesn’t tell anything about the welding integrity of the pipes,” Ruane said. “We need Smart Pigs, the units that could go into pipelines and actually inspect from the internal portion of the pipe. It’s simple to say but you put people on the moon how many years ago and you can’t invent a Smart Pig that will go through every pipe. It’s just not acceptable.”

The NTSB also released several recommendations to agencies and legislators across the state, including several for both PG&E and the CPUC.

In a statement, Pacific Gas and Electric President Chris Johns said that they “fully embrace” the recommendations and are implementing them as part of a larger effort to promote safer pipeline operations.

(Copyright 2011 by CBS San Francisco. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)


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