NTSB investigates pipeline explosion - WOWK 13 Charleston, Huntington WV News, Weather, Sports

NTSB investigates pipeline explosion

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The National Transportation Safety Board, a federal body charged by Congress to investigate transportation-related accidents, has launched an investigation into why a natural gas pipeline exploded near Sissonville Dec. 11.

The pipeline, owned by NiSource/Columbia Gas, exploded just before 1 p.m. As a result, several houses were destroyed as well as a section of Interstate-77. Robert Sumwalt, a member of the NTSB, said it is within the agency's purview to investigate how and why the pipeline exploded. He revealed some of the investigation's findings at a Dec. 12 press briefing.

According to NTSB investigators, the pipeline, referred to as SM-80, ran west to east perpendicular to I-77. When the pipe exploded, it left a crater 15 to 17 feet deep. The 20-inch transmission line was located near other lines, a 30-inch line and a 26-inch line. Neither pipe was damaged by the blast. According to Sumwalt, a section of pipe more than 20 feet long was ejected in the blast.

"That part was ejected out of the crater," he told the press.

Gas continued to flow for about an hour before valves could be manually shut off. Sumwalt said two isolation valves are located upstream and downstream from the site of the rupture and one was shut off at approximately 1:45 p.m., and the other a few minutes later.

NTSB is working to survey and document the exact location of the pipes and the parts displaced by the blast. Sumwalt said the NTSB will put together a "very detailed timeline" of the events leading up to the blast. He and others will look at Kanawha County Emergency Operations Center records and call logs and listen to 911 tapes and fire rescue recordings.

"All of this will be used to create a very precise timeline," Sumwalt said.

Sumwalt said no one has reported smelling any foul odor leading up to the blast. Only minor injuries have been reported. The NTSB is contacting possible victims to gather additional information about the explosion.

NTSB investigators are planning to look at data from NiSource's central control center in Charleston today. Sumwalt said the blast did not trigger any alarms within the central control center.

Investigators will remain in the Sissonville area for about a week. Crews are working now to crate up the portion of pipe ejected and send that back to NTSB laboratories in Washington, D.C., to be further scrutinized. Investigators also will excavate eight to 10 feet of existing line to get an idea of the condition of undamaged pipe.

Sumwalt was hesitant to reveal any additional information, saying he didn't want to cause confusion by releasing information until it had been verified. Initial reports of the size of the pipeline were muddled. The NTSB reported initially the pipe was 30-inches in diameter, while NiSource said 20 inches. Sumwalt said the NTSB was working off information initially reported to them and they had not verified the size of the pipe before releasing that information.

"We are just at the beginning of this investigation," he said.

"It's not as easy a process as you might think."

The NTSB has established an email address where residents in the vicinity of the explosion can share information.  That email address is witness@ntsb.gov.