City Blasts Pipeline Explosion Report

Investigators probing the causes of the Sept. 9 gas pipeline explosion fell far short of their goal, attorneys for the city said today in a stinging rebuke.

In addition, the review committee failed to call PG&E's bluff when it claimed a 2008 city sewer replacement caused Line 132 to burst, unleashing an 85-foot fireball that killed eight people, subjected 66 more to painful, debilitating injuries, and incinerated 38 homes, the city report says.

The California Public Utilities Commission to scrutinize the causes of the rupture, examine contributing factors within PG&E and the CPUC, and recommend guidelines to head off similar tragedies in the future.

In its official response, the city saved most of its scorn for PG&E, described as disinterested in safety matters.

It also rejected the utility company's contention that the rupture was an anomaly, the report says.

While pipe defects may be unusual, “The pervasive lack of corporate awareness of these engineering defects for almost 60 years, the absence of meaningful investigation, examination and survey of this and other pipelines in High Consequence Areas and the adoption of…methods known to be wholly incapable of detecting such engineering hazards, is totally unacceptable for this utility, this industry, and this state,” the report contends.

But the independent review panel glossed over key causes, it says.

That matters here, considering three pipelines continue to carry high-pressure natural gas through heavily populated areas in San Bruno and throughout the Bay Area.

The investigators could not be reached for comment.

They drew some kudos from the city, largely for concluding that PG&E suffers from “systemic and deep-seated problems,” city attorneys say.

“A clear example of this culture and the corporate tendency to accept pseudo-scientific risk assessments and assumptions” was revealed when the utility pressured the CPUC to rush approval of high-pressure pipelines locations. “PG&E to this day to foster fictions as a substitute for empirical analysis and engineering.”

But the investigators erred when they relied on an investigative report by the Interstate Natural Gas Association of America, of which PG&E is a member.

Studies dating back to 1992 and 1993 point to seismic problems threatening the integrity of Line 132 at a critical juncture. The Gas Association report didn't mention them.

And both the Gas Association and the independent investigators failed to consider the definitive impact of cyclic pressure fatigue on pipelines—a phenomenon that occurs with surges in pressure, weakening pipes.

PG&E has theorized that a 2008 city sewer pipe replacement prompted the pipeline rupture, drawing outrage from city officials.

“PG&E’s lack of proper integrity management over its failed, substandard, high-risk pipeline was one, if not the main, precipitating causes of the explosion," the report concludes.