The National Transportation Safety Board has concluded its investigation of the explosion of a natural gas pipeline in San Bruno, CA last year that left eight people dead. Their findings: this was “an organizational accident.” Matthew Wald covered the story for the New York Times.
According to the report, PG&E failed to properly manage the pipeline for 54 years. During the original installation of the pipe, crucial welds were missed. Not just a few welds, but half of the welds were missing. The NTSB stated that the completed pipeline was not properly inspected for safety. While the original construction defects certainly contributed to the disaster, the report also found that ongoing management and procedures were certainly contributing factors:
On the day of the accident, Sept. 9, 2010, the fatal sequence began when workers at a computerized control center in Milpitas, Calif., were replacing a power system, but their work plan was poorly drawn and resulted in sensors erroneously reporting low pressure. That led to the automatic opening of valves, raising the pressure above what was intended. Even though the pressure did not reach the maximum the pipeline was supposed to hold, it failed because workers had skipped one set of welds when they installed the pipe in 1956, investigators said. The lack of welds should have been obvious in a visual inspection, they said…
Ms. Hersman contrasted the gas utility’s poor performance in the accident with television advertisements she saw while in California to visit the explosion site. In those ads, the company said it was installing “smart meters” at customers’ homes that could tell instantly how much gas and electricity was being used, and communicate that information to the customers. But in a major transmission line, she said, “for a good half an hour or an hour, they can’t even isolate where the rupture occurred.” And months after the disaster, the company was still failing to provide timely information about problems, she said.
However, PG&E is not the only entity which bears responsibility for the tragic accident. The NTSB was extremely critical of the California Public Utilities Commission and the US Department of Transportation. According to the findings, these public entities failed in their role to provide oversight by exempting older pipelines from testing that would have easily identified the defects prior to rupture. Earlier this week, the Department of Transportation announced efforts to revise safety rules for pipelines.
The accident occurred on September 9, 2010 and was responsible for the destruction of 50 homes.
AEC Forensics 