NTSB investigators said in that case, the 95 minutes PG&E took to stop the flow of gas and isolate the ruptured line "was excessively long and contributed to the extent and severity of property damage and [increased] the life-threatening risks to the residents and emergency responders."
In a media briefing Wednesday night, Sumwalt declined to say if NiSource had taken too long to shut down the gas feeding the fire that erupted over Sissonville.
"We have seen cases where there are automatic shutoff valves and remote control valves where the pipeline can be shut off instantaneously if not very, very quickly after that," Sumwalt said. "Recently, we had an oil pipeline spill where it continued to flow for over 17 hours. There is a gamut. It can range from very quickly to a long time."
In its report on the San Bruno disaster, the NTSB urged the federal Department of Transportation to begin requiring automatic shutoff valves on pipeline located in "high consequence areas" where people, property or the environment could be seriously damaged by accidents.
"The use of either automatic shutoff valves or remote control valves would have reduced the amount of time taken to stop the flow of gas," the NTSB said in a report issued in September 2011.
Current rules from the U.S. Department of Transportation require automatic or remote shutoff valves only if pipeline companies themselves determine that installing such devices "would be an efficient means of adding protection" to the public, property and environment in the event of a release.
NTSB investigators noted that PG&E had dismissed the use of automatic or remote shutoff devices, saying that most of the damage from pipeline ruptures occur within the first 30 seconds and that the duration of the resulting fire "has (little) or nothing to do with human safety and property damage." Later, during an NTSB hearing, PG&E's senior engineer testified that conclusion was based on a review on only industry-generated reports, not government or safety group studies that reached different conclusions.
Also, NTSB investigators noted, PG&E had stated years before, during a 1997 public meeting, that safety would be enhanced by reducing the volume of flammable gas released, that a "major technological advantage is the ability to isolate the pipeline break quickly without personnel being required to be sent to operate any mainline valves."
PG&E also later said that using remote control shutoffs could have reduced the time it took to cut the flow of gas to the San Bruno fire from more than 90 minutes to about 30 minutes, the NTSB noted.
In its report, the NTSB said that studies have indicated that prolonged gas-fed fires lead to increased property damage. A congressionally mandated study, published in 1999, found that remote shut-off devices reduced property damage and public disruption, lessened damage to other utilities, and allowed emergency responders faster access to accident sites.
On its website, the transportation department's Pipeline and Hazardous Materials Safety Administration, or PHMSA, lists its response to the NTSB recommendation on shutoff valves as "under development." Agency officials did not return a phone call Thursday.
In August 2011, automatic or remote shutoff valves were among a long list of potential safety reforms that the agency sought public comments on as part of a broader initiative. No proposed rule on shutoff valves has yet emerged from the agency.
Last year, legislation introduced by House and Senate Democrats - including Rockefeller - would have mandated the PHMSA within two years issue a rule to mandate automatic or remote shutoff devices. But the final bill, approved and signed into law, includes language from a competing Republican measure that requires such a rule only if the agency determines it is "appropriate," and applies it only to new or rebuilt pipelines.
Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.