One year after San Bruno blast: Preparing for worst in pipe system 

click to enlarge Prevention: State and federal officials began considering more regulations on PG&E gas pipes after the explosion that killed eight people in San Bruno. (Getty Images file photo) - PREVENTION: STATE AND FEDERAL OFFICIALS BEGAN CONSIDERING MORE REGULATIONS ON PG&E GAS PIPES AFTER THE EXPLOSION THAT KILLED EIGHT PEOPLE IN SAN BRUNO. (GETTY IMAGES FILE PHOTO)
  • Prevention: State and federal officials began considering more regulations on PG&E gas pipes after the explosion that killed eight people in San Bruno. (Getty Images file photo)
  • Prevention: State and federal officials began considering more regulations on PG&E gas pipes after the explosion that killed eight people in San Bruno. (Getty Images file photo)

Flames were ruthlessly devouring a neighborhood for more than half an hour before the fire chief in charge of fighting them, Dennis Haag, concluded they had not been ignited by an airplane.

One might imagine he knew that because PG&E had finally informed emergency personnel that a natural gas pipeline ran through that very neighborhood, and it had blown up.

But no. Instead, Haag figured it out because the local airports had managed to account for all of their planes, and by deductive reasoning, he knew it must be something else.

One also might imagine that once it did become obvious the flames were being fueled by a 30-inch hose of combustible gas, PG&E would be on the case to turn that hose off.

But it took fully 95 minutes for the pipeline valves to be closed. PG&E had sent out someone to turn it off, but that person lacked the training or the tools to do so. They sent out another crew, but they got stuck in a crushing traffic jam.

Finally, an off-duty employee took it upon himself to go to the valves and turn them off, and within moments the worst of the firebomb subsided.

Everyone agrees this should never have happened, and should never be allowed to happen again. So federal investigators have recommended imposing regulations requiring the obvious: that a utility should provide emergency responders with information about the location, size and status of a pipeline in its area — and should immediately notify first responders if they believe a pipe has ruptured.

Federal investigators and Rep. Jackie Speier, whose district includes San Bruno, have advocated that pipeline operators be required to install automatic or remote-controlled valves on their lines, so they could be turned off as soon as a pipeline ruptures, rather than depending on a human to reach them. A law being drafted by the House Energy and Commerce Committee does not go nearly that far, but would require them to be installed on all new pipelines that travel through populated areas.

Within months of last year’s tragic accident, PG&E installed remotely controlled shutoff valves at two stations in San Bruno. PG&E officials have agreed to install the valves throughout the system, regardless of whether the government mandates doing so. This commitment comes at considerable expense: Each valve costs about $750,000 to install  — about $225 million for the 300 manual valves it plans to replace. But even this solution would be imperfect: Remote-controlled valves may not have saved lives in San Bruno, as some industry experts say most deaths occur in the first flash of an explosion. However, dozens fewer homes would likely have been destroyed.

PG&E has also had a change of heart about informing pipeline operators precisely where the lines are located.

Before San Bruno — and several weeks afterward — PG&E point-blank refused to provide the public with information about where their pipelines are, what size they are, or the condition they are in. The company repeatedly cited concerns about terrorists: Bad guys could get ahold of the information and use it to sabotage America’s infrastructure, they theorized.

Today, the utility has sent out letters to every person who lives within 2,000 feet of a pipeline, and they have created a detailed map of the locations of their transmission lines. And San Francisco’s firefighters are participating in a pilot program where their mobile data terminals show them exactly what is underground.

Haag noted that the response to the fire would not have been appreciably different had they known from the start it was  a pipeline explosion, though it would have cut through considerable confusion and focused efforts.

“If we knew it was a gas line, we certainly would have sought out PG&E management staff earlier,” he said. “We would have had a better idea of what to expect.”

Commitment to better testing

Ten months before the San Bruno disaster, PG&E inspected the natural gas pipeline running underneath the Peninsula city using a controversial method known as “direct assessment.”

Direct assessment isn’t considered as rigorous as other testing techniques. While the method can detect some forms of corrosion, it cannot detect small cracks in the pipeline or weak points in a weld — such as in the weld that failed in San Bruno.

After conducting its direct assessment inspection, PG&E determined that Line 132 was safe to continue operating.  

A year after that assumption was violently and tragically challenged, PG&E has agreed to a more rigorous standard of testing its pipelines. About 700 miles of the company’s pipelines have apparently never had any other kind of inspection done on them than a direct assessment, and PG&E has agreed to do one of two things with those: pressure test or replace.

This process, combined with installing safety valves and other safety measures, could cost about $2.2 billion. PG&E has suggested that only about a tenth of that cost would come from their profits — the rest they want to charge to ratepayers. However, consumer advocates argue that the burden of these improvements should fall on PG&E, not ratepayers, since the company should have been keeping up its system all along.

Also unresolved is what the long-term testing requirements will be: whether a single test on pipelines will be considered sufficient, or if PG&E will be required to inspect the pipes on a regular basis.  As it stands, direct assessment is still allowed and used. — Katie Worth

Chain of catastrophe

Beginning on the afternoon of Sept. 9, gas pressure swung wildly and finally built up until the explosion, at which point communication failures kept the neighborhood from PG&E help for nearly an hour and a half.

2:46 p.m. Gas control technician reports that a team will be working on broken equipment in Milpitas — work that in the coming hours leads to pressure swings in the pipes, power problems and communication failures.

4:20 p.m. A PG&E alert system indicates that pressure in the pipe has dropped extremely low, but returns to normal 12 minutes later.

5:20 p.m. Gas control center in San Francisco realizes that a valve in Milpitas has malfunctioned, causing pressure in Line 132 through San Bruno to climb above its normal 375 pounds per square inch. Over the next 50 minutes, pressure climbs up to 386 psi.

6:11 p.m. Pipeline 132 ruptures, spewing flames 200 feet in the air, and starting a fire that will kill eight people, injure dozens more, and damage or destroy 100 homes.

6:12 p.m.
First San Bruno Police Department unit arrives on scene.

6:17 p.m. Fire Department unit arrives five minutes later.

6:18 p.m. PG&E’s Concord dispatch center is notified by an off-duty employee that there’s a huge fire in San Bruno. Dispatch begins calling supervisors and on-duty employees asking for a response.

6:23 p.m. Concord dispatch  center sends a gas service representative to turn off the gas in the area, but that employee was unqualified to do so.

6:31 p.m. The gas control center in San Francisco finally contacts dispatch that they are receiving low-pressure alarms on the system and there may have been a rupture.

6:35 p.m. An off-duty mechanic who is qualified to operate valves calls dispatch center, saying he can see flames from his house and is coming into work.

6:54 p.m. Concord dispatch tells a PG&E supervisor that they have been told “a plane has crashed into a gas station and took out some houses in San Bruno” and says they’ve been requested to turn off gas and electricity to the area.

7:06 p.m. Off-duty mechanics qualified to turn off valves decide on their own to go shut off the gas.

7:30 p.m. Off-duty mechanics shut off the upstream valve, just three-quarters of a mile from the rupture.

7:42 p.m. The flames in San Bruno are reported to be diminishing.

7:46 p.m. Valves downstream from the rupture shut off.

Source:  NTSB

Breaking down the repercussions

9 California Public Utilities Commission safety inspectors before blast

100,000 Miles of pipeline the CPUC oversees

11,000 Average miles of pipeline per inspector before blast

18 CPUC inspectors now

5,500 Average miles of pipeline per inspector now

700 Miles of pipelines PG&E lacks records of ever testing

0 Dollars PG&E has so far paid in fines

$150,000-$500,000 Cost of testing one mile of pipeline

5 Years expected to take to test all pipelines

95 Minutes gas was spewing out of pipeline before valves were shut

About The Author

Katie Worth

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