Probably the most “hot button” environmental issue in the United States is the possibility of shale gas development operations compromising drinking water aquifer quality through leakage of methane or through migration of drilling, fracking, and formation fluids. There are two primary routes for methane and fluids to reach aquifers. One is the “standard” route by which barriers to such gas and fluid movement – casing and cementing around a borehole in contact with an aquifer – are faulty to begin with or over time erode and corrode to permit leaks underground. The other is the possible migration of gas and liquids from the fracking zone through cracks, fissures, old boreholes, and the like to vulnerable aquifers. Regulations are in place in the United States for the former route, and large numbers of industry studies maintain that the latter route is highly unlikely given the rock barriers that enabled gas to be retained in the shale formation in the first place.