Pacific Gas and Electric Co. (PG&E) last week disputed many of the findings about the San Bruno, CA, natural gas pipeline explosion in September 2010 that were handed down by the California Public Utility Commission's (CPUC) Consumer Consumer Protection and Safety Division (CPSD).
"It was our pipeline that ruptured and exploded because of a defective four-foot piece of pipe that should never have been put in service," PG&E stated in its 209-page response to the CPSD report of the September 2010 incident. The defective piece of pipe should not have been in the ground and PG&E stated that it has no records concerning the installation, manufacture and testing of the bad pipe segment. Nevertheless, the utility strongly disagrees with "many of the alleged deficiencies identified in the CPSD report," and assertions in submittals by intervenors.
One of PG&E's expert witnesses, Robert Caligiuri, a pipe metallurgist, concluded that the pipe segment (No. 180 on Line 132) failed because of a missing interior longitudinal weld, a ductile tear likely caused by hydro testing at about 500 psig and fatigue cracking that grew from the tear.
PG&E is attempting to prove that most of the alleged deficiencies cited by the CPSD in its report and in various intervenor testimony "are not, in fact, deficiencies," or are what the utility thinks are much less severe than alleged. "In either event [they] do not constitute violations of state or federal law," the PG&E filing said.
PG&E stated that it recognizes that parts of its gas system operations were not "as good as they could have been" prior to the explosion in San Bruno, and the utility has taken seriously "its obligation to fix shortcomings and ensure that safety is maintained as a top priority."
PG&E is contending that the CPUC safety staff have gone beyond the shortcomings that the utility has acknowledged and tried to "stack on top of this unknowing mistake a large number of alleged violations of what were then voluntary standards in 1956," when the portion of pipeline that failed was part of a relocation, or rerouting project. "But most of the standards CPSD references have nothing to do with the root cause of the pipe's failure."
"Collectively, we all have a very heavy responsibility," said CPUC President Michael Peevey last week in kicking off a Safety Leadership Conference on the same day as the filing by the utility. "We're all involved in industries that carry the potential for catastrophic consequences or failure. As leaders we are responsible, not just for policy and the bottom line, but for the safety. Many of us are here because we came up short in that responsibility."
Other speakers included National Transportation Safety Board member Robert Sumwalt, Washington [DC] Metropolitan Area Transit Authority Vice Chairman Mortimer Downey and Karlene Roberts, who heads the University of California, Berkeley, catastrophic risk management center.
Sumwalt, a former commercial pilot who later trained pilots in safety, stressed the critical role leadership plays in preventing "organizational accidents," which are caused by a combination of factors that can include lack of a safety focus; use of the wrong safety metrics or poor regulatory and internal board oversight.
Peevey commented on PG&E's 2,200 MW Diablo Canyon Nuclear Generating Plant in California as having a "good standard of safety," raising the question of whether there is not a significant gap between the combination utility's electricity and natural gas organizations. "Perhaps there is a gap in the safety cultures of the two organizations?" he asked. "I think this shows how important it is to have them at parity as we go forward; I think this is critically important."
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