Three contract workers were injured, one critically, in a fiery explosion that erupted during well testing at a natural gas-drilling site in western Pennsylvania, authorities said.
The three men were not involved with the testing but were removing water caused by melted snow at the Chesapeake Appalachia site near Avella, about 25 miles west of Pittsburgh, the company said.
The flash fire erupted at 6:15 p.m. Wednesday and involved five 500-barrel storage tanks before it was extinguished at 9:30 p.m., the company said in a release. No major environmental damage was immediately reported.
Richard Lancaster, 50, of Sardis, Ohio, remained in critical condition and Russell Schoolcraft, 48, of Clover, W.Va., in serious condition at UPMC-Mercy in Pittsburgh, hospital spokeswoman Karissa Millick said Thursday.
Frank Lancaster, 36, of New Martinsville, W.V., remained at West Penn Hospital, where his condition was not released at the request of family.
Chesapeake Appalachia, a subsidiary of Chesapeake Energy Corp., said three wells on the pad were closed after the explosion and will remain closed until an investigation is finished, the company said.
Investigators with the state Department of Environmental Protection were also at the site.
Gas drilling has picked up drastically in recent years as companies seek to extract natural gas from a rock formation beneath Pennsylvania called the Marcellus Shale.
Water mixed with sand and chemicals, some of them toxic, is forced into the wells at high pressure, shattering the underground shale and releasing trapped gas, a process called hydraulic fracturing, or fracking. Residents in communities where fracking occurs have voiced concerns about possible water contamination and other safety issues, but the gas companies say the procedure has been used safely for decades.
According to Chesapeake, no fracking was under way Wednesday at the Avella site.
State DEP spokeswoman Katy Gresh said the company followed regulations by immediately calling the agency's emergency response hotline, as well as the well inspector responsible for the region.
DEP records showed no environmental violations reported at the well site in 2010 or 2011. However, records show that Chesapeake was one of the most-punished Marcellus Shale well operators in Pennsylvania last year, racking up 149 violations and 33 enforcements.
Reported incidents included chemical and waste spills and suspicions of gas seeping out of wells. Collected fines totaled less than $12,000.
Chesapeake has also been blamed for contaminating residential wells with methane gas.
In cases involving other companies, a July explosion and fire at a shallow gas well in Clearfield County killed two Northeast Energy Management Inc. workers. In that case, a tank containing flammable materials exploded, igniting a well fire that burned for 10 hours.
Last June, an EOG Resources Inc. well in Clearfield County blew out and went out of control for 16 hours, sending polluted drilling water into nearby creeks. DEP blamed a lack of training and safety shortcuts. EOG and its contractor agreed to pay more than $400,000 in fines.