Feds come down hard on PG&E for San Bruno blast
Jaxon Van Derbeken, Demian Bulwa, Eric Nalder, Chronicle Staff Writers
Tuesday, August 30, 2011
A defective weld in the pipe segment that ruptured existed from the moment the line was buried under the Crestmoor neighborhood in 1956, said investigators with the National Transportation Safety Board.
The flaw would have been apparent if anyone had checked, either then or in the years since, the investigators said at a hearing in Washington, D.C. They planned to issue of a summary of their final report, which could influence pipeline safety regulations around the country, later in the day.
Agency Chairwoman Deborah Hersman, in her opening statement, traced the Sept. 9 disaster to PG&E's installation of a "woefully inadequate pipe," whose source remains unknown.
At the rupture site at Earl Avenue and Glenview Drive, which sits at the low point of a canyon, PG&E cobbled together six short pipe pieces, or pups, allowing the line to negotiate the curve of the canyon.
Hersman and safety board investigators said none of the pipe pieces, which were made by bending steel plates around cylinders, met PG&E or industry standards. The one that failed had been welded along its longitudinal seam from the outside, but not the inside, leaving it prone to failure.
Investigators said PG&E had been running gas through those pups at unsafe pressures for decades, until one finally gave way.
The safety board investigators said the rupture had initiated at a crack that probably formed during a past incident of stress, but could not say how or when that occurred.
They said the weak pups would not have withstood specialized testing, such as the use of high-pressure water, for defective longitudinal seam welds. But PG&E never did such tests on the line, and checked the pipe only for corrosion. Company records erroneously indicated that the line was seamless and thus had no seam welds.
The company, Hersman said, "exploited weaknesses in a lax system of oversight, and regulatory agencies that placed a blind trust in operators to the detriment of public safety."
The use of the defective pipe "was compounded over the years by a litany of failures" by PG&E, Hersman said, "including poor record-keeping, inadequate inspection programs, and an integrity management program without integrity."
"It was not a question of if this pipeline would burst," Hersman said. "It was a question of when."
Ravi Chhatre, the investigator in charge of the federal agency's probe, called the disaster that destroyed 38 homes "an organizational accident" resulting from "widespread deficiencies" in PG&E's operation.
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