WASHINGTON — Federal accident investigators lay the blame squarely on Pacific Gas & Electric Co. for a gas pipeline explosion that killed eight people and decimated a suburban neighborhood near San Francisco last year, according to a final report and video released Monday.
The National Transportation Safety Board posted online its 140-page report and a 20-minute video, pulling together information gathered in a yearlong investigation of the Sept. 9, 2010, explosion and fire in San Bruno, Calif. Escaping gas fed a pillar of flame 300 feet tall for more than 90 minutes before workers were able to manually close valves that cut off gas to the ruptured pipeline.
Dozens of people were injured and more than 100 homes destroyed or damaged.
The board unanimously agreed at a meeting last month that the accident was caused by what NTSB chairman Deborah Hersman called "a litany of failures" by PG&E, one of the nation's largest gas companies, as well as weak oversight by regulators. She called the explosion the nation's most significant pipeline accident in the last decade, not only in terms of its destructiveness, but also for the significant safety lapses it revealed.
The report, which essentially enumerates findings and conclusions presented at the August meeting, said events that led up to the accident began more than 50 years ago with the installation of substandard pipe with inferior welds. PG&E didn't discover the problem because it failed to conduct proper pressure tests or visual inspections of the pipeline. Key records relating to the pipeline's origin are missing. Other records incorrectly describe the section pipe that ruptured as being seamless rather than welded, which led the gas company to place a maximum gas pressure limit on the line that was too high for the pipe to withstand.
Destruction caused by the accident was significantly worsened because of PG&E's ineptness. Long after the company's control room operators knew the source of the fire was the rupture of a large transmission line they neglected to relay that information to 911 operators or emergency responders, who thought they were dealing with a plane crash. The fire burned at least an hour longer than it would have if PG&E had installed automatic or remote-controlled shut-off valves.
As a result of the accident, the board has issued 39 safety recommendations to PG&E, gas pipeline operators, and federal and state regulators. But a safety advocate who has followed the case said it's not clear whether Congress and federal regulators will embrace some of the more significant recommendations.
For example, NTSB has recommended installation of automatic shut-off valves on existing pipelines, but legislation under consideration in Congress only addresses valves for newly-constructed lines – a far less expensive proposition, said Carl Weimer, executive director of the Pipeline Safety Trust.
"Everyone knows doing that – going back and putting in these valves in or doing these pressure tests that should have been done 40 years ago – is a costly thing," Weimer said. "It would cost hundreds of millions of dollars. I think Congress is hesitant to require regulations that would cost that much money without a clear sense of how many lives would be saved."