There are high levels of methane in a Dimock Township, PA, water well in an area of the community still off-limits to some natural gas drilling operations because of a past methane incident and state environmental regulators want to find out why.
The Pennsylvania Department of Environmental Protection (DEP) began the investigation after it received a complaint of turbid water in a private well and later found “high levels” of methane dissolved in the water and airborne gas accumulating in the well, spokeswoman Colleen Connolly said.
Tests at four other water wells did not show elevated levels of the gas, she said, but the state plans to continue monitoring.
The home is near the Costello and Gesford well sites operated by Cabot Oil & Gas Corp. the state is evaluating as part of its investigation, she said. It is also in a 9-square-mile area where the DEP has barred Cabot from drilling new wells until methane the state first linked to the company’s operations in 2009 subsides in 18 water supplies.
The water well now under investigation was not part of the earlier incident, Connolly said.
Cabot spokesman George Stark said crews discovered a line that vents shallow methane from the Costello well froze during a recent period of cold weather. Since the plug cleared, levels of gas in the water well have decreased.
“It appears to be a small and localized event,” he said and added that Cabot will now monitor all its vent lines during extreme weather events.
The company is providing the home with bottled water.
The Gesford wells under evaluation underwent hydraulic fracturing, or fracking, in November after the state lifted some of its restrictions on Cabot’s operations in the area. The process of injecting chemically treated water and sand into rock formations at high pressure releases the gas trapped in the shale.
Fracking has not been the direct cause of gas migration incidents in the region. Instead, past problems ended up tied to faulty construction of gas wells.