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Most U.S. gas lines not inspected with latest technology

This map shows the U.S. natural gas pipeline network in 2009.
This map shows the U.S. natural gas pipeline network in 2009.Department of Energy /
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Almost two-thirds of America’s natural gas pipelines — including the 30-inch main that exploded last week in San Bruno, Calif. — are susceptible to potentially deadly faults because they can’t use the industry’s best technology for testing and cleaning them, federal records show.

The 2½-foot-wide gas main exploded Thursday night, killing at least four people, injuring dozens more and destroying scores of homes. The California Public Utilities Commission has ordered an inquiry and told Pacific Gas and Electric Co., the utility that owned and operated the pipe, to inspect all of the state’s gas pipelines for potential problems.

PG&E says it’s still too early to know why the pipe blew up. But disclosures since the blast make it clear that a trifecta of vulnerabilities meant the San Bruno main was prone to fail sooner rather than later:

  • It was 54 years old, at the outer limit of its expected 50-year lifetime.
  • It was made of steel. regulators have long regarded steel — which is used in about half of all gas pipelines and nearly two-thirds of the nation’s larger gas mains — as a safety hazard because it’s too rigid and easily corrodible.
  • Because of the gas main’s age and the twists and turns of the pipeline, PG&E couldn’t use robots that would have been the best way to maintain and inspect it.

Those robots are known as “smart pigs,” so-called either because of the squealing noise they make as they root through pipes or as an acronym for "pipeline intervention gadget," according to the Pigging Products & Services Association. The sensor-laden pigs are smart little critters that ride along on the flow of gas, cleaning interior surfaces, removing corrosive water, sending back data on possible structural flaws and even plugging some leaks themselves.

But records filed with the Office of Pipeline Safety, a division of the U.S. Pipeline and Hazardous Safety Administration, show that about 63 percent of the nation’s natural gas pipelines still aren’t inspected by the pigs because they’re too old or too twisty to be retrofitted to use them.

“These gas lines are definitely a ticking time bomb, and that is why people are concerned, and that’s why federal and state regulators need to intervene,” said Mark Toney, executive director of the Utility Reform Network, a nonprofit California watchdog group.

‘This is a national safety issue’
Pigs are the most effective way to inspect and maintain pipelines, with the most advanced of them approaching 95 percent reliability in detecting problems, the Gas Research Institute said. But PG&E President Chris Johns said at a news conference that the entire 51-mile segment of pipeline that included the faulty main in San Bruno couldn’t be inspected with pigs because of its twisty configuration.

Federal law — specifically, the Pipeline Integrity Management Program — requires all newly constructed lines to be inspected by pigs. But much of the nation’s natural gas infrastructure was installed in the 1950s and 1960s, and the law doesn’t require retrofitting of those older lines.

Three factors are primarily responsible for the slowness to adopt pigging and other state-of-the-art technology, said the Southwest Research Institute, a nonprofit applied engineering foundation that studies pipeline safety for the National Energy Technology Laboratory:

  • The “considerable cost” of installing and running pigs. There’s no rule of thumb because each installation is unique, dependent on expenses for excavation and replacement of buildings and other infrastructure that must be demolished or moved. But after the Pipeline Safely Improvement Act went into effect in December 2002, the American Gas Association, the industry’s trade group, projected that compliance would average out to about $10,000 per mile of pipeline per year.
  • Service disruptions that occur when infrastructure has to be torn up to do the work.
  • Unsuitability. While federal law calls for pigging whenever possible, “various geometrical and geographical constraints” — like the terrain through which the San Bruno pipe ran — can make pigs unusable.

As the years have gone by without needed upgrades, “neighborhoods have grown and sprawled over these gas pipes,” said Jim Hall, former chairman of the National Transportation Safety Board, which is in charge of the San Bruno investigation because the federal pipeline bureaucracy is part of the Transportation Department.

“This a national safety issue in many local communities because of a lack of local rules and regulation” to beef up standards where federal rules don’t apply, he said.

Sen. Barbara Boxer, D-Calif., said utilities’ foot-dragging on maintenance and emergency planning had opened her eyes, adding, “I think many questions must be answered by all of us whose job it is to protect our people.”

Until those questions are answered, said Rep. Jackie Speier, a Democrat who represents part of San Francisco and San Mateo County in Congress, “the question that everyone’s asking is:  ‘Is this going to happen in my community?’”

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