In releasing another 3,000 pages of data Monday on the San Bruno, CA, natural gas pipeline rupture and explosion last year, the National Transportation Safety Board (NTSB) said it would make a report and final decision on the probable cause when the board meets Aug. 30 in Washington, DC.
NTSB said it might be adding postings to the already voluminous dockets filed on its website, in addition to the ones released Monday that include a description and assessment of the pipeline integrity management (IM) and safety program conducted by Pacific Gas and Electric (PG&E) on the segment of its Line 132 that failed last Sept. 9.
PG&E utility President Chris Johns praised NTSB’s work. Among eight actions that the San Francisco-based utility has been taking, some in response to mandates from state and federal regulators, Johns said PG&E has begun to replace and upgrade many “older gas lines,” adding automatic or remote shutoff valves and adopting state-of-the-art pipeline inspection technologies.
The NTSB documents, which included no analysis by the federal agency, said PG&E conducted internal camera inspections of Line 132 nine different times between Sept. 29 and Oct. 28. The inline inspections covered various segments in and around the area where the rupture and explosion occurred.
The documents also included the acknowledgment that PG&E was “aware that there are some manufacturing and construction threats on Line 132, and that the pressure had been raised three consecutive times on the line. The issue of automatic shutoff values and remote control valves was also raised, showing that PG&E had repeatedly looked at installing more of them but never took much, if any, action.”
The NTSB documents cite the California Public Utilities Commission (CPUC) in 2005 as taking PG&E to task for not following through on what its audit at the time identified as “the most significant integrity management program concern/issue.”
“PG&E had no process in place to evaluate automatic shutoff valves or remote control valves,” the CPUC said. “Furthermore, PG&E proposed in its IM plan to wait until December 2006 to develop this process.”
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