The Pennsylvania Department of Environmental Protection (DEP), in an 18-page report released Wednesday, said human error likely led to a deadly explosion and fire that raged for days at a Chevron Appalachia LLC site in February (see Shale Daily, Feb. 11).
The report concludes the majority of a six-month investigation and sheds more light on what caused the Feb. 11 fire and subsequent blast that prompted four fire departments, state regulators and well control experts to respond and remediation efforts that lasted for weeks.
According to the report, Chevron officials told state regulators that a failed gland nut and lockscrew assembly, used to secure wellhead equipment, had been ejected causing natural gas to leak from the wellhead. DEP made the same conclusion in its report, adding that "the source of ignition is not known at this time. As natural gas well development frequently requires numerous pieces of equipment or devices that could act as an ignition source, resolving this question is far less critical than understanding how the assembly came to be ejected, and what can be done to prevent a recurrence of this event."
The fire occurred at the three-well Lanco pad in Dunkard Township, about 70 miles south of Pittsburgh in Greene County. It left Cameron International employee Ian McKee, 27, of Morgantown, WV, dead and another wounded.
The Lanco 7H well was the first to catch fire and it did not extinguish itself until Feb. 15. Specialists from Houston-based Wild Well Control had capped both the 7H, and the Lanco 6H, which burned for one day, by Feb. 25 (see Shale Daily, Feb. 18; Feb. 13).
During remediation efforts, Chevron officials found the lockscrew assembly 73 feet from the wellhead, according to the report. At the time, Chevron suspended all of its Pennsylvania operations to ensure the integrity of its wells in the state.
"Although the exact reason why the gland nut and lockscrew were ejected from the wellhead is not conclusively known," the DEP said in its report, "the suspected cause of the failure is that the assembly was loosened several days before this incident and was not properly re-secured," concluding that "human error" likely resulted in the ejection of the assembly.
DEP said workers were gathering at the site for a safety meeting on the morning of the fire when two employees, most likely McKee and the injured worker, walked toward the 7H to investigate a hissing sound.
"As they approached the well, natural gas leaking from the 7H wellhead under high pressure ignited," the report said. "In the opening seconds of the fire, one of the two employees was injured and the other disappeared from view. When employees assembled at the rally point, they realized that there was one person missing."
In April, the DEP sent Chevron nine violations stemming from the explosion (see Shale Daily, April 11). Chief among them was the allegation that Chevron refused unrestricted access to properly identified DEP personnel at the wellsite. DEP reiterated the claim in highlighting the problems experienced during the response in its report, saying "Chevron's emergency response plan was sufficient, although communication with DEP was too guarded."
The company continues to face the possibility of several fines related to the incident. In response to the DEP's allegations, Chevron said in April that it was merely following protocol to ensure the safety of all those on site.
In its report, the DEP put forward eight recommendations on how to better install and use lockscrew assemblies at well sites across the state. It added that some aspects of its investigation are still ongoing.