NTSB to release preliminary study results within one month - WOWK 13 Charleston, Huntington WV News, Weather, Sports

New details are emerging into what led to the natural gas explosion in Sissonville on Tuesday. 

Investigators with the National Transportation Safety Board (NTSB) released Friday that they have found corrosion on the exterior of the pipe. A six foot section to the east of the explosion point will be sent to Washington D.C. for analysis along with a 10 foot section to the western portion. There was no speculation as to what would have caused the corrosion. 

Investigator Robert Sumwalt also said at the news briefing that Columbia Gas was notified at 12:50 p.m. of the explosion from an another gas company. Investigators have found that Cabot Gas contacted the company after being called by a witness. Investigators are searching for that caller.

Earlier investigation noted the explosion happened at 12:41 p.m., some 9 minutes before Columbia became aware. Members of the Sissonville Volunteer Fire Department left the station at 12:41 p.m. Investigators are interviewing members of both companies and ensuring the clocks match. 

Corrosive Engineer Joe Payer with the University of Akron said exterior corrosion is the most common type of wear on buried natural gas piping. 

"The metal corrodes and gets thinner," said Payer. "The remaining metal can no longer contain the pressures."

Despite the relatively common issue of corrosion, Payer said much of the buried pipeline in the United States is aging. 

"One of the greatest challenges we have in corrosion control and mitigation is coming up with better ways of analyzing these pipes for their degree of safety and risk," said Payer. "We talk about performance assessment. The question is how safe is it, how long will it last and how confident are we in those predictions."

This, the fourth news briefing, will be the NTSB's last in South Charleston. Any other information will be released from Washington D.C. While a full report could take more than a year, a preliminary report could be released with 30 days.