"Natural gas invading at least nine water wells in Dimock Township has
been tracked to the Marcellus Shale or a similar formation being tapped
by drilling crews working in the area.

In an effort to fix the problem, regulators from the state Department of
Environmental Protection have asked Cabot Oil & Gas to vent its natural
gas production wells around the Carter Road area, just south of
Montrose, said Mark Carmon, a spokesman for the agency. The intention is
to give the gas seeping in the ground and collecting in water supplies a
means to escape."

....

"Tests show gas found in water is "production gas," Carmon said, meaning it escaped from the kind of geological formation commonly trapped for energy. The state has ruled out the possibility it was the product of organic conditions in shallow ground water that sometimes affect water wells."

Natural gas in water wells has N.Y. officials on alert
Pennsylvania homeowners notified of dangers
By Tom Wilber • twilber@gannett.com • Staff Writer • January 25, 2009
http://www.pressconnects.com/article/20090125/NEWS01/901250335/1001

Excerpted from the article:

"Natural gas levels found in four water wells in Dimock Township, Pa., could indicate a broader, potentially dangerous problem, and homeowners in that area are being encouraged to vent their wells.

Following an explosion Jan. 1 that shattered an 8-foot cement well cover, four wells with unacceptable levels of natural gas have been taken off-line in the township.

In the past few days, letters and fact sheets were sent to about 20 homeowners south of Montrose, Pa., alerting them to the dangers of gas trapped in wells and encouraging them to vent them, said Pennsylvania Department of Environ-mental Protection spokesman Mark Carmon.

Meanwhile, DEP officials are analyzing tests from about 20 homes in the area to determine whether the gas found in the wells is from natural ground conditions or a byproduct of drilling operations by Cabot Oil & Gas. The Houston-based energy company is drilling dozens of wells more than a mile deep to tap the gas-rich Marcellus Shale formation."

....

"Geological theories

"It's possible, but not probable, that gas could migrate from the Marcellus Shale to the aquifer 6,000 feet above, said Terry Engelder, a Penn State University geoscientist with expertise in the Marcellus.

"The rock formations in and around the area carry a lot of fractures with them," he said. "There is a slim possibility that if a company like Cabot came along, man-made fractures in the Marcellus could connect up with other fractures in more shallow units."

A more likely scenario, he said, is gas from natural sources has been moving through shallow soils for some time, and residents are now just beginning to notice."

,,,,

"Natural gas is not poisonous, so it does not present a drinking hazard, said Diane O'Hora a spokeswoman for the Broome County Department of Health. Combustion is the main concern.

Some are less worried than others.

Raymond Osterhout, a Wind-sor resident, has had gas in his water for years, he said, although there are no natural gas wells anywhere near his property.

To him, it's more of a novelty than a problem."

My Comment: While methane is considered non-toxic - much of hat assumption is based on respiration. But even then, methane will displace oxygen and can cause suffocation. Further, little has been studied on its effects in the blood, or as it is processed through major eliminatory organs.

Beyond that, once it is in a household water supply - and if not properly vented - it can accumulate and cause an explosion in hot water heaters, etc.

Further, benzene, toluene, and other toxics accompany methane in unprocessed natural gas.