A new study says toxic fluids used in drilling and hydraulic fracturing likely escaped an unlined borehole and migrated thousands of feet into residential drinking-water wells in Pennsylvania.
At least three wells were contaminated with dangerous levels of methane and other substances in 2010. The incident was one of several involving Chesapeake Energy that prompted state regulators to levy a record $1 million fine against the driller.
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Penn State University researchers say they detected minute amounts of a chemical compound often found in drilling and fracking fluids. Their study was published Monday in the Proceedings of the National Academy of Sciences.
The study does not implicate the fracking technique itself. Researchers say the toxic fluid probably escaped the gas well while it was being drilled.