Feds blame PG&E for San Bruno explosion

September 1, 2011

Federal investigators issued a scathing critique of PG&E this week, citing what one official called “baffling” mistakes that led to the San Bruno gas pipeline explosion last September, killing eight people and destroyed 38 homes. [LA Times]

The National Transportation Safety Board (NTSB) also indicated that PG&E exploited the lack of monitoring by regulators and lacked a workable emergency response plan that could have helped prevent the devastation that occurred in the Bay Area community.

Tuesday’s report marks the first time officials have assigned blame for the incident.

The explosion is “the story of flawed pipe, flawed inspection and flawed emergency response,” said Deborah A.P. Hersman, who chairs the NTSB. “It was not a question of if the pipe would fail, but when.”

NTSB officials said PG&E took almost 95 minutes to shut off the gas spewing from the pipeline in San Bruno. The NTSB contends that a lack of automatic shut-off valves and valves that can be closed remotely contributed to the slow response.

But officials said the problems that led to the disaster began with mistakes PG&E made decades earlier.

When the utility relocated the pipeline in 1956, the seams running along the length of the pipe were welded only on the outside, a defect that led to the rupture and a problem that officials said could have been easily discovered with visual inspections.

The company, which operates the pipeline, also mistakenly listed the pipeline section as seamless in its records, when, in fact, it was welded.

The NTSB asserted that the poor welding would not have have met industry standards at the time, leading the board to conclude that PG&E ignored or overlooked the defect.

The utility missed opportunities to address shortcomings in its pipeline systems after similar systematic problems surfaced during two earlier ruptures, NTSB officials said, one in San Francisco in 1981 and another in Rancho Cordova in 2008.

In a prepared statement, PG&E President Chris Johns praised the investigation as thorough and said the company would take the NTSB’s findings seriously.