No injuries were reported but flames and smoke from the blast could be seen as far as 20 miles away, residents told local media. Area police told CBS News the fire was "very large—if you can see it from your house, evacuate."
"It sounded like a freight train coming through, or a tornado, and the sky lit up bright orange, and then I got up and looked out the window and flames were shooting I don't know how far into the sky," Tina Heath-Chaplin, of Moundsville, told WPXI.
TransCanada—the same company behind the Keystone pipeline—said the explosion has been contained and an investigation is underway.
"As soon as the issue was identified, emergency response procedures were enacted and the segment of impacted pipeline was isolated. The fire was fully extinguished by approximately 8:30 a.m," the company commented Thursday.
"The cause of this issue is not yet known," TransCanada continued. "The site of the incident has been secured and we are beginning the process of working with applicable regulators to investigate, including the Pipeline and Hazardous Materials Safety Administration."
Robert Burrough, the director with the Pipeline and Hazardous Materials Safety Administration's Eastern Regional Office, told the Pittsburgh Post-Gazette the affected line is likely TransCanada's $1.6 billion, 160-mile Leach XPress pipeline, which started service in January.
Russ Girling, TransCanada president and CEO said at the line opening, "This is truly a best-in-class pipeline and we look forward to many years of safe, reliable, and efficient operation on behalf of our customers."