Fracking firms say they don't know when they're working through possible sources of drinking water

The oilfield service companies that perform hydraulic fracturing for natural-gas companies told congressional investigators they don't know when they drill wells into rock strata that may be sources of drinking water. That prompted Democratic Reps. Ed Markey of Massachusetts and Henry Waxman of California, the House Energy and Commerce Committee chairman, to ask "10 oil and gas producers who hire the service companies to provide a list of all hydraulically fractured wells in or near such sources," Mike Sorghan of Environment & Energy Daily reports. Waxman's letter to well operators asking for the information also sought information on recovery and disposal of "produced water" and other fluids that come back out of the well.

Chris Tucker, spokesman for industry group Energy in Depth, told Sorghan, ""The basic geological reality of shale gas exploration is the formations we fracture are separated from the formations carrying potable underground water by thousands and thousands of feet -- and millions and millions of tons -- of solid, impermeable rock," If the chairman is looking for some additional information on that scientific phenomenon, or on the steps that operators take at every wellsite in America to ensure what happens inside the wellbore has no way of communicating with what occurs outside it, that's a conversation we look forward to being part of."

Some of the companies who told investigators they didn't know which wells were located near drinking water sources signed a memorandum six years ago with the Environmental Protection Agency agreeing not to use diesel fuel in such wells. "It is not clear how the companies could honor the agreement if they did not know whether they were pouring chemicals into sources of drinking water," Sorghan writes. Fracking has been used the industry for decades but "questions about drinking water contamination have mounted in the past few years as the process has opened up vast reserves in shale formations in new areas," Sorghan writes. (Read more, subscription required)