"This appears to be a violation of the Safe Drinking Water Act," the letter says. "It also means that the companies injecting diesel fuel haven't performed the environmental reviews required by the law."
The Energy Policy Act of 2005 created a loophole that exempts companies drilling for natural gas from disclosing the chemicals involved in fracking operations that would normally be required under federal clean water laws. The loophole is commonly known as the "Halliburton loophole" since former Halliburton CEO Dick Cheney was reportedly instrumental in its passage.
The natural gas industry and its political allies have fought hard to maintain the loophole, despite mounting concerns over how fracking may contaminate public water supplies. The industry maintains that the practice is environmentally safe, but its critics point to reports of fracking-related health hazards, including homeowners contending with flammable tap water.The EPA is currently conducting a study to determine the safety of the hydraulic fracturing process, scheduled to be completed next year. According to the New York Times, an agency official told congressional investigators that it had ASSUMED the use of diesel in hydraulic fracturing had ended years ago.