SAN BRUNO, Calif. – Nearly nine months after federal investigators began probing a deadly pipeline explosion near San Francisco, a California utility quietly revealed its ruptured line had sprung a gas leak in a spot only a few miles away years before, a top safety official revealed Wednesday.
National Transportation Safety Board Chair Deborah Hersman called Pacific Gas & Electric Co.'s recent disclosure of its leak in 1988 "troubling," as she announced three new safety recommendations at a news conference a few feet from the gaping crater left by the San Bruno blast.
"If it took them months to realize they had a leak on the same line just nine miles south of the rupture site and only now we're hearing about it, that's very troubling," Hersman said. "What we're concerned about is the process that prevented them from providing this to us sooner."
PG&E spokesman Brian Swanson said staff members only recently turned up the documents revealing the prior leak in a satellite office and told federal investigators soon thereafter.
"We provided all the available documents we had to them, and we are still investigating and researching our records," Swanson said. "We've acknowledged several times since the tragedy that our operations and record-keeping practices aren't where they should be."
Learning about past problems so long after the investigation began hampers federal investigators' ability to quickly determine what caused the pipeline buried four feet under a residential street to burst last year, Hersman said.
Even though the company ultimately replaced the leaking portion of the pipe, the recent disclosure underscores the inadequacy of PG&E's record-keeping, she added.
U.S. Rep. Jackie Speier, a Democrat whose district includes San Bruno, said the new leak report raised additional concerns about PG&E's ability to locate its own records and showed regulators had been "asleep at the switch."
"I'm very dismayed to find that at this late date, PG&E is providing NTSB with what is critical information," she said. "There is a part of me that feels that this area that had the leak should be excavated."
The NTSB is still probing what caused the Sept. 9 blast, which sparked a fireball that engulfed a suburban neighborhood and killed eight people, injured dozens and laid waste to 38 homes overlooking the San Francisco Bay.
Hersman said one of the recommendations is meant to press the company to set up new procedures so emergency responders are immediately and directly notified when a possible pipeline rupture occurs.
She also recommended that the Pipeline and Hazardous Materials Safety Administration, which enforces federal rules for the safe operation of interstate pipelines, urge pipeline operators nationwide to improve their emergency communications plans and share more information about their systems with first responders in local communities.
On Wednesday, Hersman also toured the blocks torched in the inferno and met with families who lost relatives, local firefighters and PG&E executives.
In the wake of the accident, the California Public Utilities Commission is considering a proposal that would require all utilities in the state to submit plans to pressure-test or replace the untested segments of their gas transmission lines — such as the pipe that exploded last year.
PG&E is also under orders to review its records for weld defects on its lines, but utility officials recently told state regulators they would miss the June 20 deadline to hand over those documents to the commission. Wednesday afternoon, following Hersman's announcement, the commission approved PG&E's proposed extension, granting the company another year and a half to complete its search.
Swanson said Wednesday that company employees detected the small methane leak in the line more than two decades ago, and found it was prompted by a defect in a weld running lengthwise down the transmission pipeline.
NTSB investigators also found weld defects in a segment of the same high-pressure transmission line that blew up in September, nine miles north.
Swanson said regulations in 1988 did not require the company to immediately report the leak to authorities. Commission spokeswoman Terrie Prosper did not say whether the utility ultimately had done so, but said the old leak may not have been sufficiently large or significant to require a report.
Lori Irving, a spokeswoman for the Department of Transportation, said she could not comment on the prior leak, or whether it had been reported, because that was part of the ongoing NTSB investigation.
Glen Stevick, an expert in piping and structural analysis in Berkeley, said the 1988 leak should have served as a wake-up call for the utility to perform pressure tests on its old pipes coursing beneath people's homes.
"If you have miles of pipe of that vintage the odds of having some small leaks are quite high," Stevick said. "But no one stepped back and said 'do we have this kind of defect elsewhere and how do we figure that out?'"
Garance Burke can be followed on Twitter at http://twitter.com/garanceburke.