Three workers were burned when a fire broke out at a Chesapeake Energy Corp. drilling site in Washington County, PA, on Wednesday night.

Chesapeake said the incident occurred at its Powers Well Site, located in Independence Township in the Marcellus Shale play, close to the West Virginia border.

The company said a temporary well-testing operation was being conducted at the time of the accident. “The injured workers were not part of these tests, but were on location performing routine maintenance on the site. [They] were removing water from the location as a result of the snow melting.”

Chesapeake said three wells on the pad were closed, or shut-in, using valves at the surface when the incident occurred. A flash fire caused the first of five 500 bbl condensate storage tanks to catch fire, which ignited the others.

Katy Gresh, spokeswoman for the state Department of Environmental Protection (DEP) told NGI’s Shale Daily that the fire started at about 6:15 p.m. EST among five metal tanks used to store condensate.

“It was an ignition of a volatile vapor coming off the condensate itself that ignited the fire,” Gresh said. “I don’t want to characterize it as an explosion, in the sense that something blew up and there was shrapnel everywhere. It certainly made a loud boom, and I can understand why some of the neighbors thought it sounded like an explosion.”

According to Gresh, the wells at the drilling site were hydraulically fractured last week and were not affected by the fire. She said the DEP’s well inspector for Washington County and emergency response personnel were on the scene throughout the night. It took about three hours and 15 minutes to extinguish the fire.

Chesapeake also made clear that hydraulic fracturing was not taking place at the time of the accident. “There have been some early news accounts attributing this incident to hydraulic fracturing,” the company said. “This is not true as hydraulic fracturing was already finished and complete on this site.”

The company said the three victims are 48-year-old Russell Schoolcraft of Clover, WV, a roustabout for H&H Oil Field Services; Richard Lancaster, 50, of Sardis, OH, a truck driver, and Frank Lancaster, 36, of New Martinsville, WV, also a truck driver.

According to Chesapeake, Schoolcraft and Richard Lancaster was taken to the University of Pittsburgh Medical Center Mercy Hospital in Pittsburgh, while Frank Lancaster was transported to West Penn Hospital in Pittsburgh. Frank Lancaster’s family declined to have his condition released.

“According to safety procedures, all the men were wearing flame resistant clothing at the time of the accident,” the company said. “Our thoughts and prayers are with these men, their family and friends and we wish them a speedy and full recovery. We hope to provide them privacy as they recover.”

Gresh said investigators with the DEP, the state Bureau of Oil & Gas Management and water quality specialists arrived at the site Thursday to begin an investigation, which is continuing. Chesapeake said the wells would remain shut-in until the investigation is completed.

“We still have not determined the actual cause of the fire,” Gresh said, adding “Chesapeake had dikes and secondary containment structures in place prior to this that helped to contain everything. There’s been no evidence of any surface runoff, and there are no streams or wetlands nearby.”