New research is providing some of the first scientific evidence that a controversial gas drilling technique can contaminate drinking water.
The study published Monday found potentially dangerous concentrations of methane gas in water from wells near drilling sites in northeastern Pennsylvania, although not in central New York, where gas drilling is less extensive.
But in an unexpected finding, the team of Duke University scientists did not find any trace of the chemicals used in the hydraulic fracturing process in 68 wells tested in Pennsylvania and Otsego County in central New York.
In hydraulic fracturing, or fracking, water, sand and chemicals are injected underground to crack the rock and get natural gas to flow into a well. Critics of the technique have worried more about the chemicals since companies have refused to make public the proprietary blends used and some of the ingredients can be toxic.
On average, water from wells located less than a mile from drilling sites had 17 times more methane than water tested from wells farther away, according to the study published Monday in the Proceedings of the National Academy of Sciences.
Methane is not known to be toxic, but in high concentrations it can be explosive and cause unconsciousness and even death, since it displaces oxygen needed to breathe.
Of the 60 wells tested for methane gas, 14 had levels of methane within or above a hazard range set by the Department of Interior for gas seeping from coal mines -- all but one of them near a gas well. In nine wells, concentrations were so high that the government would recommend immediate action to reduce the methane level.
The study published Monday found potentially dangerous concentrations of methane gas in water from wells near drilling sites in northeastern Pennsylvania, although not in central New York, where gas drilling is less extensive.
But in an unexpected finding, the team of Duke University scientists did not find any trace of the chemicals used in the hydraulic fracturing process in 68 wells tested in Pennsylvania and Otsego County in central New York.
In hydraulic fracturing, or fracking, water, sand and chemicals are injected underground to crack the rock and get natural gas to flow into a well. Critics of the technique have worried more about the chemicals since companies have refused to make public the proprietary blends used and some of the ingredients can be toxic.
On average, water from wells located less than a mile from drilling sites had 17 times more methane than water tested from wells farther away, according to the study published Monday in the Proceedings of the National Academy of Sciences.
Methane is not known to be toxic, but in high concentrations it can be explosive and cause unconsciousness and even death, since it displaces oxygen needed to breathe.
Of the 60 wells tested for methane gas, 14 had levels of methane within or above a hazard range set by the Department of Interior for gas seeping from coal mines -- all but one of them near a gas well. In nine wells, concentrations were so high that the government would recommend immediate action to reduce the methane level.
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