NTSB: Corroded pipe, lack of inspections led to gas explosion in W.V.
A corroded gas pipeline that had not been inspected in more than two decades contributed to an explosion in 2012 that destroyed homes and melted a section of Interstate 77 in Sissonville, W.Va., the National Transportation Safety Board said on Monday.
The explosion, just north of Charleston, grew into a raging fire 1,100 feet along the pipeline and more than 800 feet wide. It left a nearly 15-foot-deep crater just off the interstate and turned a picturesque valley with rural homes into a scorched moonscape with mailboxes melted to wood posts and charred foundations.
“Remarkably, no lives were lost in this accident,” NTSB Chairman Deborah A.P. Hersman said. “But the potential for tragedy was clearly there.”
The pipeline was owned by Columbia Gas Transmission, a subsidiary of Columbia Pipeline Group, whose Operations and Project Delivery President Shawn L. Patterson said in a statement had implemented a “comprehensive response program” because of the blast.
“This was a difficult situation for all of us,” Patterson said. “But we recognize and embrace the critical importance of learning from the Sissonville event and applying what we learn to our pipeline system and operational procedures.”
The 20-inch interstate transmission line ruptured at 12:41 p.m. Dec. 11. Despite several alerts at a Columbia Gas control center, the controller did not realize an explosion had happened for 12 minutes, the report said.
A line shutdown took an hour to complete and began only when someone from another gas company told Columbia about the rupture.
Columbia had no automatic shutoff or remote control valves on the line, the report said.
The pipeline had not been inspected or tested since 1988, the NTSB found. A rocky backfill likely contributed to corrosion.
Because the line was in a sparsely populated area, it was not classified as a high-consequence area that would result in stricter testing regulations, the report states.
“We continuously check our lines with foot patrols and/or aerial patrols and maintain and inspect corrosion control systems along our pipelines,” company spokeswoman Katie Dupuis Martin said in an email. “We are a safe company with employees who are committed to keeping their neighbors safe and to following regulations outlined for us by federal and state agencies.”
Officials said it was lucky that nobody was seriously injured. The explosion happened while many people were at work. Traffic on I-77 was light.
“An intense fire raged directly across the interstate for nearly an hour,” the report said. “Had the accident occurred during commuting hours, when traffic would have been significant, severe or fatal injuries could have occurred.”
The blast closed northbound lanes for 14 hours and southbound lanes for 19 hours while crews resurfaced the roadway.
In the valley below the highway, damage extended for hundreds of feet in all directions from the rupture point.
Columbia Pipeline Group subsidiaries serve customers in more than 16 states and have about 15,000 miles of pipeline.
In Pennsylvania, Columbia Gas Transmission operates 7,385 miles of distribution gas lines, which provide natural gas to homes and are much smaller than the large transmission lines such as the one that ruptured, said Jennifer Kocher, a Pennsylvania Public Utility Commission spokeswoman.
Columbia Gas Transmission is replacing pipelines across Pennsylvania, Kocher said. The PUC reported no significant incidents in 2013.
Dupuis Martin said Columbia Pipeline Group spent $300 million in 2013 on a pipeline modernization, part of a five-year, $1.5 billion project. The group replaced more than 50 miles of pipeline last year and will replace 35 miles in 2014, she said.
Chris Togneri is a Trib Total Media staff writer. Reach him at 412-380-5632 or firstname.lastname@example.org.