West Virginia officials ordered Antero Resources to provide more information Thursday about a July 7 well explosion that killed two people and injured six others.
James Martin, chief of the state Department of Environmental Protection's Office of Oil and Gas, wrote that the Denver-based energy company's two-page report about the incident was "incomplete."
Antero's report on the incident was dated Wednesday, the last possible day to legally submit it based on the DEP's July 10 order.
Alvyn Schopp, an Antero spokesman, said the company filed its report on the last possible day because "every day we have more information. We wanted to make sure we had the most thorough information when we filed the report."
Jason Mearns, 37, of Beverly, W.Va., and Tommy Paxton, 45, of Walton, W.Va., were subcontractors working on the well and died at the West Penn Hospital burn unit from injuries related to the New Milton, W.Va., explosion, about 50 miles southwest of Morgantown.
Both men died in the past nine days, weeks after the initial incident.
According to Antero's report, the explosion was caused by "the presence of and an accumulation of gas from the storage tanks on location" and "weather conditions exacerbating the accumulation potential of said gas."
The report also cites "a concentration of heavier than methane hydrocarbons in the gas mixture; and an apparent ignition source near the C&R quad-plex skid pump" as causes of the explosion.
Antero claims no pollutants were released or associated with the incident, but in its latest order, the DEP asked "for a rationale expressing how it was deemed that no pollutants were released in the incident."
The DEP also ordered Antero provide all of the information they used to support their findings about the causes of the explosion.
"The original Cease Operations order is still in effect and will remain in effect until Antero provides a response that satisfies the requirements outlined in the original order," DEP spokeswoman Kathy Cosco wrote in an email.
Antero hopes to reactivate the well once the DEP is satisfied, Mr. Schopp said.
In its report, Antero said it is working on several measures to make its wells safer, including requiring that workers wear portable gas monitors, re-evaluating equipment layout and using taller storage tanks for flowback to provide "the highest possible outlet of any gas releases."
Molly Born contributed. Alex Zimmerman: firstname.lastname@example.org or 412-263-3909. Twitter @AGZimmerman.