DENA POTTER
Associated Press

CHARLESTON, W.Va. (AP) - For years, critics have recommended that natural gas companies be required to install automatic or remote shut-off valves on pipelines to avoid just the kind of explosion that leveled homes and melted a West Virginia interstate this week. And yet ever since a similar blast destroyed eight apartment buildings in New Jersey 18 years ago, the accidents keep happening. And fires rage - sometimes an hour, sometimes longer - while someone struggles to cut off the flow of fuel.

Federal investigators said it took Columbia Gas Transmission more than an hour to manually shut off the gas that fueled Tuesday's inferno near Sissonville, about 15 miles from Charleston.

The company's owner, NiSource Gas Transmissions & Storage, refused to answer questions on how many of its pipelines were fitted with automatic or remote shut-off valves, with a spokeswoman saying it was too busy cooperating with investigators to provide such information.

An investigation is under way to determine what caused the explosion and whether Columbia responded quickly enough. Four homes were destroyed and an 800-foot section of Interstate 77 had to be replaced, but no one was seriously injured in the explosion that sent flames as high as nearby hilltops.

The National Transportation Safety Board, which is conducting the West Virginia investigation, has long advocated requiring valves that could shut off gas in such situations within minutes.

Instead of requiring someone on the scene to manually shut off the flow of gas, an automatic valve closes when a sensor detects fluctuations in pressure or other criteria. A remote switch can be triggered from afar if an engineer sees questionable data. Currently, manual valves are required at intervals - from every 2 ½ to 10 miles - based on population density.

Safety officials argue the automatic or remote valves allow the gas to be shut off much quicker, giving firefighters access to the damaged area much sooner. But industry officials complain they're too expensive to install on the more than 2.6 million miles of pipeline already crisscrossing the U.S.

Columbia alone transports 3 billion cubic feet of natural gas per day through nearly 12,000 miles of pipelines snaking through 10 states.

"Safety costs money, and it can either cost money up front, or it can cost innocent lives and untold tragedy to others who are in the proximity of these pipelines when they explode," said Jim Hall, chairman of the NTSB from 1994 through January 2001. "The price is set. It's just do we pay it up front now or pay it later?"

Hall has been pushing for the change since 1994, when the Edison, N.J., explosion injured 29 people and left hundreds homeless. One person died of a heart attack. That was the first time emergency and automatic shut-off valves were proposed, he said.

"The industry has failed to step up," Hall said Friday. "The companies' attitude is, in many cases, unless it's required, they're not going to do it."

While Congress signaled support for the automatic or remote valves in a law signed by President Barack Obama this year, it remains uncertain what final regulations will look like and whether they will target only new or completely replaced pipelines, or also include the existing ones.

"I suspect we'll see something coming forward. How inclusive it is will be the key," said Carl Weimer, executive director of the Pipeline Safety Trust, which supports requiring the valves, especially in more populated areas.

The law gives the U.S. Secretary of Transportation the final say in the regulations, and it would mandate them only when it's "economically, technically and operationally feasible" to do so.

West Virginia Sen. Jay Rockefeller, who has proposed even stronger restrictions, said recent high-profile gas explosions like that in his home state underscore the need for stronger oversight. The investigation into the Sissonville explosion may reveal that further steps are needed, he said.

"Pipeline safety is a serious matter, one that shook West Virginia quite literally this week," said Rockefeller, who chairs the Senate Commerce Committee, which overseas transmission pipeline safety.

The U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration is studying the issue, but it has seen pushback from the gas industry over concerns the costs are too high and the benefits too uncertain.

In its 300-plus-page draft report submitted in October, researchers found installing the automatic or remote valves could be feasible and even cost-effective in some circumstances, but not all. A final report is due in 2013.

In public comments to the draft report, the Interstate Natural Gas Association of America said valve automation "can help protect some property by allowing earlier firefighter access, but does little to protect people." Most of the deaths and severe injuries are caused in the first few seconds after an explosion, the group argued, rather than after prolonged exposure.

In his comments, American Gas Association counsel Philip Bennett said his organization supported installing the valves when it was feasible, but argued it should be determined on a case-by-case basis. "Rapid, indiscriminate, mandatory installation" would not improve safety, he said.

But Hall said that "flies in the face" of the evidence from the 2010 pipeline explosion in San Bruno, Calif., that killed eight people. The NTSB determined the damage could have been significantly reduced with the use of automatic or remote shut-off valves. In that case, it took the company more than an hour and a half to shut off the gas.

"The industry record on this has been dismal," he said. "And now, with the amount of new pipe that's being put in place in the U.S., as well as the age of the pipe that is in the ground, it is important that government and industry come together to effectively provide safety programs that address some of these outstanding recommendations."

Meanwhile, the NTSB is looking into whether Columbia's pipeline was shut down properly.