Crew Feared Pipeline Pressure
Wednesday, March 9, 2011 @ 03:03 PM gHale
Shortly before a fiery pipeline blast that left eight dead in San Bruno, CA, utility crews raced to stop gas pressure surges they feared would cause a “major, major problem.”
Operators knew as long as half an hour before the Sept. 9 blast that a botched repair job in a nearby control station was letting natural gas flow unabated, but felt powerless to fix the problem remotely, according to Pacific Gas & Electric Co. records.
According to call logs released by the federal government: “Something opened that shouldn’t have,” one unnamed gas control operator told a colleague 20 minutes before the explosion. “They’re scrambling in Milpitas right now trying to figure out what the hell opened and what’s going on.”
The National Transportation Safety Board is still investigating what caused the explosion, which employees called a “living nightmare” later that night.
Eight people died, dozens suffered injuries and 55 homes destroyed after a giant, gas-fueled fireball swallowed portions of a neighborhood in San Bruno.
Federal investigators have said the power failure at the control station, a major intersection for gas transmission lines about 30 miles from the blast site, allowed a regulating valve on the line feeding San Bruno to open fully and for pressure to rise.
But at 6:40 p.m., nearly half an hour after the explosion, workers were still debating whether a plane had hit, a gas station blew up or it was a pipeline accident.
PG&E spokesman Joe Molica said in a statement Tuesday the utility has been working with regulators since the accident to improve the safety of its system.
“We are not, however, waiting for mandates from legislators or regulators: PG&E already is making pipeline safety changes,” he said. “We have launched a number of initiatives to reevaluate, restructure and strengthen our gas system operations and the management of our natural gas system. We have brought in independent experts to help us with our review of some of our gas control practices, including alarm management systems.”
The section of pipe that ruptured first went in the ground in 1956. An NTSB examination after the accident revealed it had a seam and inferior welds, although PG&E records had inaccurately identified the pipe as being seamless.