NTSB Finds Faulty Welds on San Bruno Pipeline

By Published On: January 28, 2011

A Pacific Gas & Electric pipeline that exploded in San Bruno killing eight people and destroying 37 houses had a number of faulty welds, according to a National Transportation Safety Board report released Jan. 21. Safety board metallurgists examined an approximately 50-foot-long excavated section of the pipeline and discovered defects including “lack of penetration, incomplete fusion, burn through, slag inclusion, crack, porosity, undercutting, and excess reinforcement” in numerous welds. Lack of penetration, the report said, means there was not enough metal in the welded seam. PG&E president Chris Johns called the report “another important step” in finding out what went wrong and in preventing future pipeline failures. “The more we learn the worse it gets,” said Mindy Spatt, spokesperson for The Utility Reform Network. “First we find out that PG&E didn’t know whether the pipe had any welds or not, now we find out that there were numerous defects in the welds.” The safety board stated the document was the first of six “factual reports” it plans to release by March 1 on the explosion of Pacific Gas & Electric’s 30-inch diameter pipeline Sept. 9. The reports are to come in advance of three days of federal regulatory hearings on the accident scheduled to begin March 1. Pictures in the federal report show a pipeline that is fractured, has some rust, and in one case is missing asphalt coating designed to protect against corrosion. The photos also display pipe bending. After the accident, to preclude tension, PG&E and the CPUC allowed gas pressure reduction on old pipes throughout its system and in the San Bruno area. “All pipelines in PG&E’s system that are of a state and vintage similar to the line in San Bruno are continuing to operate at pressures that have been reduced by 20 percent,” Johns stated. PG&E was heavily criticized for alternatively increasing and reducing gas pressure in the pipeline—which can cause stress—before the accident occurred. In response, the utility maintained it operated within authorized pressure levels that provide for an adequate margin of safety. The utility is closely monitoring 100 sections of gas pipeline for repair or replacement, said Katie Romans, PG&E spokesperson. She explained that the utility installed the San Bruno pipeline in 1956 to serve new housing developments in the area. It branches off an older pipeline on the San Francisco Peninsula built in 1948. Romans said the utility has never pressure tested the San Bruno pipeline, though it has assessed the pipeline for safety. In contrast, she said the utility has pressure-tested the majority of its 1,800 miles of high pressure pipeline. Growing concern about aging pipelines after the accident last September prompted PG&E to examine all its pipeline safety records. It is pulling them into a central data base to respond to orders from regulatory agencies, including the state commission and the safety board. She explained the documents currently are held at various PG&E offices and facilities up and down the state. The utility plans to advise regulators on its progress in February, she said, and to provide a final report in March. The regulatory oversight, though, did not satisfy The Utility Reform Network. The ratepayer group, along with some San Bruno residents, called for state regulators to initiate an open investigation Jan. 26. San Francisco city attorney Dennis Herrera joined TURN in filing a petition asking the CPUC to issue an order instituting investigation. “Concerns over regulatory laxity and pipeline safety must be addressed with a transparent, public investigation,” said TURN executive director Mark Toney. He maintained that without an open investigation, the public cannot be assured that regulators will ever “impose fines and remedies, and determine who is liable for any increased costs” stemming from the incident. Mike Peevey, California Public Utilities Commission president, said Jan. 27 that commission would vote Feb. 24 on consolidating past and future natural gas pipeline safety issues for all the utilities, not just PG&E. At the time “we will consider appropriate enforcement action,” he said.

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