A U.S. Department of Energy study concluding possibly hazardous chemicals used in hydraulic fracturing, or ''fracking,'' at gas and oil wells does not pollute groundwater is good news.
Actually, it is only common sense: Fracking occurs thousands of feet below aquifers. For chemicals to migrate that far up into groundwater would defy gravity.
Still, the DOE should continue to monitor drillers. As we have pointed out repeatedly, failures in well casings passing through the groundwater zone could result in pollution. While the danger is very slight, it is one against which state and federal agencies should guard.