In the ongoing heated debate over hydraulic fracturing, can we all at least agree that chemical contamination does not come from the mostly water and sand (with a little bit of chemical additive) that is pumped a mile or more below the earth’s surface? The general public hears from the media echo chamber that “fracking threatens water supplies” and assumes that somehow, in some way, chemicals will rise up from a mile below the ground and contaminate water wells and aquifers near the surface. It just doesn’t happen—it’s a physical impossibility. Here’s an excellent analogy recently printed in Popular Mechanics to put it in perspective:
The idea stressed by fracking critics that deep-injected fluids will migrate into groundwater is mostly false. Basic geology prevents such contamination from starting below ground. A fracture caused by the drilling process would have to extend through the several thousand feet of rock that separate deep shale gas deposits from freshwater aquifers.
According to geologist Gary Lash of the State University of New York at Fredonia, the intervening layers of rock have distinct mechanical properties that would prevent the fissures from expanding a mile or more toward the surface. It would be like stacking a dozen bricks on top of each other, he says, and expecting a crack in the bottom brick to extend all the way to the top one. What’s more, the fracking fluid itself, thickened with additives, is too dense to ascend upward through such a channel.*
So if contamination of water supplies does not happen from below the ground, from the fracking process itself, how might it happen? Spills on top of the ground. Truck accidents. Railroad accidents. The things that can and do happen every day across America in non-gas industries. Trains have accidents and carloads of chemicals get spilled. Trucks have accidents along the highway and chemicals get spilled. Gas drilling is no different. From time to time (and very infrequently) something will spill on top of the ground. There is no industrial business on earth that is 100 percent accident-free. It’s just not reasonable to force gas drilling to be accident-free when no other business is held to the same standard.
The fracking process itself is not the problem and is not the reason a water supplies would ever become contaminated with chemicals.
*Ocean Resources/Popular Mechanics (Sep 12, 2011) – Is Fracking Safe? The Top 10 Myths About Natural Gas Drilling: Myth #4