Pacific Gas & Electric Co. (PG&E) just revealed the pipeline that exploded last year in San Bruno, CA, had a previous leak less than nine miles away.
That news was “very troubling” said the National Transportation Safety Board (NTSB) Chair Deborah Hersman. The September 9 blast left eight people dead and injured dozens while destroying 38 homes.
Hersman pointed out PG&E’s disclosure of its leak in 1988, as she unveiled three new safety recommendations at a news conference at the blast site.
“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 just 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.
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 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.
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.
PG&E is also under orders to review its records for weld defects on its lines, but utility officials 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 company employees detected the small methane leak in the line more than two decades ago, and found the leak came from 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.