PG&E says it will not release the locations of its most dangerous gas-transmission pipes, citing homeland security interests, but local legislators say they’re pushing back.
At a public meeting Monday night at the Church of the Highlands in San Bruno, the utility whose transmission pipeline ruptured last week resulting in at least four deaths and 37 destroyed homes told concerned residents it would answer inquiries from individual customers about pipeline locations, but would not release a list or map.
“I think that every resident has a right to know if there’s a transmission line in their backyard or their front yard or their block,” replied Rep. Jackie Speier, to applause from residents who posed written questions to officials from PG&E, the National Transportation Safety Board and other state and federal agencies in front of more than 100 other audience members.
Utility officials said PG&E will provide as much information as it can to individuals who ask.
“We’ll write back a notification that gives you a sense of where that line is within limits so that we don’t get so specific as to create a security issue but enough to get a sense for where it is,” said Edward Salas, senior vice president of engineering and operations.
The meeting was decidedly less hostile than Saturday’s town hall meeting, during which residents responded angrily to PG&E. Still, several residents posed similar questions about the location of the transmission lines Monday, saying they feared the possibility of future explosions. Some answers, including a PG&E official’s insistence she didn’t know the location of the pipeline’s manual valves, provoked boos. Some residents didn’t know where to point their frustration.
“As a homeowner, is there any way I would know I was living on top of a 30-inch gas line?” one resident asked.
The demands came after a report by The Bay Citizen on Saturday revealed that PG&E determined that a segment of the pipeline close to the rupture site had an "unacceptably" high risk of failure. In a 2009 report outlining a proposal to replace the section of Line 132 at a cost of $5 million, PG&E officials wrote: "If the replacement of this pipe does not occur, risks associated with this segment will not be reduced. Coupled with the consequences of failure of this section of pipeline, the likelihood of a failure makes the risk of a failure at this location unacceptably high."
The utility company also identified other risky pipelines in the area and mentioned a list of “top 100 highest risk line sections.”
“We’ll get that,” Speier said, when queried after the meeting. “We’re going to get that list.”
At an earlier news conference Monday, Chris Hart, the vice chairman of the National Transportation Safety Board, said “high risk” refers to the population density surrounding the area of pipes, not just the condition of the pipe itself.
The 28-foot-long piece of metal pipe blown out in the explosion is under heavy scrutiny. The pipe was on its way Monday night to a metallurgy lab in Washington, D.C., for analysis, the next step in the NTSB’s investigation.
Hart said investigators are considering the pipe a key piece of evidence and will inspect it for signs of fatigue, corrosion and physical damage. They're also looking at seismic records, the history of excavation and construction, the condition of the valves and data from the control room.
While newer pipes can simply be bent into a curve, the 1956 pipe and other older pipes throughout the country were constructed with a middle seam and cobbled together into curves with individual, smaller pieces called "pups," said NTSB spokesman Peter Knudson. Experts say the welded seams leave more opportunities for the pipes to corrode, leak or catch fire if there's a disturbance.
The question investigators are asking is, "What caused the pipe to be breached?" Hart said.
Hart has previously noted that maintenance of a pipe is more important than its age, an idea mirrored by some experts who say older pipelines exist across the country.
"It's very common, especially in the East Coast," said Reinold Tagle, president of Rextag Strategies, a company that maps pipelines across the United States. PG&E has more than 6,000 miles of transmission lines in California. "If you consider the hundreds of thousands of pipelines in the ground right now, that fact that a segment of a few feet failed is an amazing odd."
But the life span of steel transmission pipes is typically between 30 and 50 years. The pipe that exploded Thursday was 54 years old. PG&E sets aside funds every year to replace pipes, and had planned to make repairs to Line 132 in 2013.
Still, Tagle and others say the most common cause of pipeline explosions are outside disruptions, most often caused by construction, a facet of the NTSB's investigation.
The NTSB is looking at records of construction work on and near water and sewer lines which were found running closely underneath and perpindicular to the gas line. Thus far, Hart said investigators have found no visible signs of damage. Nor has the agency received any troubling drug and alcohol toxicology test results from PG&E employees.
"We'll be interviewing witnesses, including people from PG&E, over the next few days," Hart said.
Meanwhile, the NTSB has turned the site of the explosion back over to the city of San Bruno and PG&E so infrastructure can be restored.