The effort that Columbia workers had to go through to shut off the flow of gas after the explosion also became clearer during the hearing.
Deborah Hersman, the chairwoman of the National Transportation Safety Board, which is investigating the explosion, said Columbia workers had to hand crank the valves to get them closed.
In a brief interview after the hearing, Hersman said two Columbia employees took turns applying 10-20 pounds of pressure to the valves "scores" of times to shut off the flow of gas. That happened at a nearby compressor station. The station, which is to the west of the explosion, sends pressurized gas eastward to customers nearer to the coast. The station supplies gas to all three nearby lines and all valves for all three lines were closed.
There were six valves to shut off at the compressor station. Two of the valves at the station required hand cranking, two were hydraulic and two were electric, Hersman said.
It took about an hour to shut off the flow of gas.
During the hearing, Rockefeller and Manchin both heard about the merits of automatic or remote shutoff valves. The valves automatically shut off the flow of gas to a pipeline under certain conditions. The remote valves allow the gas company to remotely shut off the flow of gas.
Rick Kessler, the president of the board for the Pipeline Safety Trust, an advocacy group, said companies should invest in technology to ensure they can quickly stop the flow of gas to damaged lines. He noted that cars, TVs, garages and drones the United States uses to kill people in foreign countries all use remote control technology.
"Yet somehow we find it acceptable that an industry can use 1960s technology," Kessler said, referring to the gas transmission industry.
Columbia had trouble identifying which of the three nearby pipelines had exploded, Hersman said.
The company's Charleston control room saw pressure drop but could not tell why because the information was not specific enough. Hersman said the configuration of the gas transmission system was "masking the drop in pressure."
NiSource executive vice president Jimmy Staton said his company was committed to preventing future accidents. Just days ago, Columbia received federal approval for a multi-billion upgrade of its aging pipeline system.
The NTSB is continuing to investigate the December explosion.Contact writer Ry Rivard at ry.riv...@dailymail.com or 304-348-1796. Follow him at www.twitter.com/ryrivard.