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For years the drilling industry has steadfastly insisted that there has never been a proven case in which fracking has led to contamination of drinking water.

Now Environmental Working Group, an advocacy organization engaged in the debate over the safety of fracking, has unearthed a 24-year-old case study [1] by the U.S. Environmental Protection Agency that unequivocally says such contamination has occurred. The New York Times reported [2] on EWG's year-long research effort and the EPA's paper Wednesday.