NEW MILTON - The investigation has begun into a natural gas well explosion that burned five workers in Doddridge County over the weekend.
State and federal investigators and independent teams hired by Antero Resources are looking into the incident.
An explosion occurred around 4 a.m. Sunday at the well site in New Milton.
Work on the nearly completed Hinterer 1H well near New Milton in Doddridge County has been halted while the state Department of Environmental Protection, the Occupational Safety and Health Administration and two independent safety firms hired by Colorado-based Antero investigate what went wrong.
David Belcher, assistant chief of enforcement for the Office of Oil and Gas in the West Virginia Department of Environmental Protection, said they have had people at the site Sunday and Monday and will continue to have people there throughout the investigation.
Antero Resources has had instances recently involving fires and people being burned at other work sites, which are also being reviewed in relation to this incident, Belcher said.
Investigators are trying to determine what caused this incident.
"We are trying to locate the source and cause of this and that is still under review," Belcher said. "Anything at this point would just be speculation."
Antero vice president Al Schopp said all five victims were taken with varying degrees of burn injuries to a treatment center near Pittsburgh. He did not release the men's names or their conditions.
The crew was in the final stages of completing the well, Schopp said, and was inserting a narrow production tube into the metal casing around the drilled hole when methane gas ignited.
"They were getting ready to put the well into service," he said. "There was some source of gas and something ignited it.
"We don't know what ignited it."
Antero has begun an internal investigation and two independent firms, hired by the company, are conducting investigations to determine what happened.
All operations at the site have ceased and won't continue until the investigation is completed, Schopp said.
A key part of the investigation will be talking to the men who were there.
"The people involved in this action will need to be interviewed," Schopp said. "We don't know when that will happen."
DEP officials said Monday the blast ruptured two tanks containing flow back water that Antero had been reusing, but the secondary containment system captured the fluid as designed and none left the site.
There was no contamination to nearby streams, officials said, and the nearest home about a half-mile away was unaffected.
DEP investigators suspect that methane vapors inside one of the tanks exploded, officials said, but they are uncertain about what ignited the explosion.
Investigators are looking at whether it might have been a pump that the crew was working on, but DEP officials said the mechanics of the blast will be OSHA's focus.
Prentice Cline, area director for OSHA's Charleston office, said he can't comment on an active investigation but confirmed his agency remained onsite Monday. OSHA has six months to complete its work.
The explosion is the latest of several high-profile incidents for Antero in West Virginia.
Last August, three workers at the company's Cottrill No. 3 well in Harrison County were injured when methane from several hundred feet below ground ignited and triggered a fire on the drilling rig floor.
The DEP cited Antero for failure to maintain well control at the pad near Sycamore.
Two months before that, a drilling operation in the Sardis area of Harrison County hit an aquifer and inadvertently repressurized a handful of old water wells. That created a backyard geyser at least 10-feet high and several smaller gushers, but no one was injured.
Schopp said at the time that workers had been drilling an initial well hole with just fresh water and air when the bit became stuck. Rather than turn the air flow off, the crew left it on as they tried to withdraw the drill.
That effectively charged up the aquifer, and the trapped air sought an escape. The crew was still thousands of feet away from oil and gas deposits.