CHARLESTON, W.Va. (AP) — A federal investigator probing a powerful explosion and fire Tuesday that charred Interstate 77 in West Virginia said Friday that a ruptured natural gas pipe had areas consistent with external corrosion.
National Transportation Safety Board member Robert Sumwalt said the pipe will undergo further analysis at an NTSB lab.
"That's exactly what we want to find out — what caused that corrosion and what could have prevented the corrosion?" Sumwalt said.
The NTSB is trying to determine the cause of Tuesday's explosion in Sissonville, which destroyed four homes and damaged a large swath of I-77. There were no serious injuries.
Sumwalt said investigators have been provided Columbia Gas Transmission records about the pipe's age, when it was installed and whether it had a corrosion prevention system.
"Now what we need to do is to comb through those records, very carefully look at them and then compare them to actually what the pipeline was," he said.
During an investigation into a 2010 deadly pipeline explosion in San Bruno, Calif., the NTSB found that PG&E records were inaccurate on key points.
"What they told us what was in the ground was not actually what was in the ground," Sumwalt said. "So even though we've been provided those (Columbia Gas Transmission) records, we need to verify that."
Investigators have said alarms didn't sound at Columbia Gas Transmission's Charleston control room during the explosion.
A Columbia Gas control room worker first learned about the accident from another company, Sumwalt said. The worker received a call 10 minutes after the blast from a controller at Cabot Gas, who had been contacted by someone on the outside.
The NTSB plans to interview the Cabot Gas employee and attempt to locate the outside caller, Sumwalt said.
Earlier Friday, Columbia Gas Transmission chief executive Jimmy Staton released an open letter to the community saying the company is committed to helping investigators pinpoint the cause of the explosion and ensure the pipeline is safe.