State and congressional lawmakers moved Tuesday to impose new requirements for automatic or remote-controlled shutoff valves on pipelines after last week's San Bruno natural gas conflagration raged for nearly two hours before the fuel supply could be stopped.
Much of the destruction, including to many of the 56 destroyed or damaged homes, apparently came in the period after the initial explosion, some officials said.
Workers for Pacific Gas & Electric reportedly could not get to manually operated valves on the high-pressure, 30-inch pipeline, the utility said. The intense heat from a blowtorch-like blaze also held firefighters at bay, as wind-whipped flames jumped from home to home, officials said. At least four people were killed and dozens were injured.
U.S. Rep. Jackie Speier (D-San Mateo) plans to introduce a bill early next year to require automatic shutoff valves on all transmission pipelines running through residential neighborhoods, said Richard Steffen, a top aide.
And state Assemblyman Jerry Hill (D-San Mateo), who represents San Bruno, said he would introduce legislation in Sacramento later this year to require either remotely activated valves or automatic shutdown devices in large natural gas pipelines. Such safety systems could have stopped the gas flow "in five minutes and would have prevented a tremendous amount of damage," he said.
Federal and state governments do not require operators to install automatic shutoff valves, leaving it up to the discretion of the company that owns the pipeline. But that policy now will be reexamined "given what the situation is," said Julie Halligan, deputy director of the California Public Utility Commission's Consumer Protection and Safety Division.
Emergency responders should not have to "wait another half hour or so" to close manual valves "because the gas is still there feeding the fire," she said. On Monday the PUC ordered the company to determine where it would be prudent to replace manual values with automated valves.
Christopher Hart, vice chairman of the National Transportation Safety Board, which is the lead agency probing the explosion, also said he was considering recommending automatic shutoff values on transmission pipelines in populated areas. "That is one of the questions that we'll be looking at," he said.
Another question is to what extent the fire in the Crestmoor neighborhood interfered with efforts to shut off the gas.
Geisha Williams, PG&E's senior vice president for energy delivery, told residents at a meeting Monday evening that it took the utility about an hour and 46 minutes to stop the gas. She blamed part of the delay on the fire, saying that it was unsafe for workers to approach the valves.
But Hart, of the NTSB, said the valves were a mile and a mile-and-a-half on either side of the blast site. He declined Tuesday to say how the fire might have interfered with shutting off the gas.
The safety value — and limitations — of automatic shutoff valves have been hotly debated in the gas pipeline industry for years. Such valves might help reduce fire damage after a line failure, said Terry Boss, vice president of the Interstate Natural Gas Assn. of America. But they don't prevent pipeline explosions, which typically cause the most harm to people nearby, he said. In addition, sensors can give false indications of a problem, leading to a sudden, unnecessary shutdown of gas supplies, he said.
"In some cases they work. In some cases, they don't work," he said. Some experts contend that the industry has resisted increased regulation, including the installation of valves, because of the cost.
New requirements for pipeline shutoff valves would be "very controversial," said Theo G. Theofanous, a chemical and mechanical engineering professor at UC Santa Barbara, who served on a major federal panel assessing pipeline risks.
"You are talking about huge expense," said Theofanous, a specialist in large, rare man-made disasters. "They don't want to do anything that costs any money." And, he said, high-tech automatic and remote valve control systems can be much more costly and demanding to properly maintain.
But automatic and remote-controlled shutoff valves are essential so a pipeline operator can isolate damaged portions of a system for repairs or to protect public safety, said Bret Lane, Southern California Gas Co.'s vice president for field operations.
"What we try to do from a system design perspective is locate these valves in areas, such as going across an active fault area, in the event of an earthquake," Lane said. "The best way to isolate problem areas is by having the segments between automatic valves be as short as possible."
PG&E, which has both manual and automatic valves, did not provide details Tuesday about its valve network.
In addition to requiring automatic shutoff valves, Speier wants to mandate detailed disclosure of pipeline locations. "It shouldn't be in someone's frontyard," Steffen said.
Connell reported from Los Angeles. Hoeffel reported from San Bruno. Lifsher reported from Sacramento.