It was faulty welding, investigators say, that precipitated the September gas line explosion in San Bruno, Calif., that killed eight people and destroyed dozens of homes.
Yet, when the utility company Pacific Gas & Electric had the opportunity to fix that stretch of pipe in the early 1990s, the company rejected the idea, based on the justification that the welds were of no danger.
Company documents uncovered by the San Jose Mercury News show that before a $12 million project was completed in 1994 to reduce the risk of pipeline ruptures in San Bruno, PG&E officials downplayed the risk of problems with the ultimately deadly stretch of line 132 that was to explode less than two decades later.
“Most of line 132 does not need to be replaced at this time, as it was installed using welding methods that meet current standards,” concluded a 1992 report from PG&E’s geosciences department.
However, federal authorities investigating the disaster reported in January that the welding defects that led to the blast date back to the pipeline’s construction in 1948.
U.S. Rep. Jackie Speier, D-Calif., who has emerged as a persistent critic of PG&E, expressed dismay over the revelations, and said she would ask the National Transportation Safety Board, which oversees pipeline accident investigations, to widen the scope of its probe.
“What we see here is a pattern where PG&E has made decisions not to put safety first,” Speier said. “At some point in their history they shifted from safety first to expedience first. Where can we trim a budget? Where can we reduce a cost?”
The 1990s project was designed to help limit the damage of potential pipeline ruptures caused by earthquakes. While large sections of line 132 were moved, the project stopped some 300 yards short of the portion of the pipeline that exploded.
The Mercury News also uncovered a 1993 letter from PG&E property acquisitions manager Janice Van Gutman that shed light on why the company neglected to install automatic shutoff valves. The issue has been another focus of the federal investigation and of subsequent plans to improve pipeline safety.
“Automatic shut-off valves are not foolproof,” Van Gutman wrote, adding that an “accidental or unnecessary” shutdown of a transmission line could disrupt service to 347,000 customers. “Purging mains and relighting these customers would cost over $12 million and would take several months to complete,” she added.
In September, it took PG&E personnel 90 minutes to turn off the manual crank valve, during which time the pipeline continued fueling the fire. The company announced the partial replacement of its manual valves with automatic valves last week.
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