Fractious debate
Rachel Ehrenberg’s feature story on hydraulic fracturing “The Facts Behind the Frack, (SN: 9/8/12, p. 20) spurred a big response from readers. We received letters voicing strong opinions on both sides of the fracking debate. The article was intended as an overview of what science has to say about the risks of fracking and, due to space constraints, could not cover every aspect of the issue. Here is a selection of the letters we received.

“The facts behind the frack” was right on the money — timely and well balanced. As a geophysicist, I’ve been asked by numerous acquaintances to explain the issue. As is often the case, the explanations are nuanced and qualified, as you say in the article, indicating the process is probably safe if properly regulated. Good job.
John Bodine, Naperville, Ill.

I found “The facts behind the frack” most informative. I was once a petroleum geologist, and I am pleased that this article shows a realistic and balanced picture of the benefits and possible problems of gas production via fluid fracking into shales.
Glen Stripling, via e-mail

Your illustration is dominated by “thousands of meters” of undisturbed horizontal beds of solid rock between the drilled layer and the water table. “Local geology” can indeed permit methane and fracking fluids to migrate upward, but so can typical geological folds, faults and cracks. 
Ralph McGrew, Binghamton, N.Y.

The article “The facts behind the frack” was a useful summary, but left out one important part of the debate, the so-called Halliburton loophole. Why does the fracking industry insist on exemption from environmental regulations? Claiming “trade secrets” to hide essential components of their operations is little more than a smoke screen to prevent the public from discovering the hazards of which the industry is very well aware. Until the transparency Zoback admits has been missing is fully available, the public has every right to be suspicious and alarmed, and their “hysteria” is not at all “misplaced.”
Michael Herzog, Naples, N.Y.

The article section “Is fracking fluid hazardous?” mentions that some 750 chemicals were in use by natural gas companies from 2005 to 2009. Not long ago, I learned that organophosphates make up part of a list of permissible compounds for fracking fluid. Organophosphates are substances closely related to nerve agents used in chemical warfare. Is there any truth to this? 
Peter Klausmeyer, Lexington, Mass.

Many companies use their own formulations, some of which can be found at, a registry of chemical information provided by industry. Organophosphates do act on the nervous system and are widely used as pesticides, but the website does not list any organophosphates as currently in use for fracking fluid. —Rachel Ehrenberg

Questions such as “Is fracking fluid hazardous?” are ludicrous. Fracking fluid is extremely hazardous, as the article goes on to prove. Do two other stories in the same issue “Extreme heat rising worldwide” and “Groundwater use outpaces supply,” (SN: 9/8/12, p. 10) take place on a different planet? Fracking hastens climate change and uses billions of gallons of freshwater. It doesn’t take a mathematician to add up the environmental and health problems and note that this sum far exceeds the benefits.  
Kimberly H. Danforth, Clifton Park, N.Y.

There is no mention of the horrific toll this practice takes upon pristine lands. The carving of permanent roads and pads, the incredible environmental destruction, the belching of pollutants and climate-changing gases from thousands of truck journeys to each well, the exemption of these practices from EPA standards, the constant venting of fumes, the greenhouse gas emissions relative to other fuel sources or renewable — virtually none of these are discussed in this woefully incomplete story.
Lucas Lackner, Berkeley, Calif.  

Where does the fracking water come from? Is water trucked in from a distant site? It seems the “environmental footprint” has to include the water source. 
Pat Rapp, New York, N.Y.

Water use and disposal is an important part of fracking’s footprint and differs depending on where the well is drilled. In semiarid or arid climates such as Texas, water use may be more of a concern than in wetter regions. There are similar concerns with how to dispose of the wastewater, which may be injected into wastewater wells, sent to wastewater treatment plants or used for deicing roads in winter, depending on the region.  —Rachel Ehrenberg

The sedimentary rocks in which hydrocarbons are found are composed of thousands of individual horizontal layers with different compositions and mechanical properties. Such laminated systems are extremely resistant to the propagation of fractures (for example, abalone shells and plywood). Thus, as your article correctly states, incidents of groundwater contamination are likely due to other aspects of gas extraction such as improperly plugged wellbores or poor cement isolation rather than to fracking.
Bill Koerschner, Farmington, N.M.

One might expect higher water methane levels in areas with high levels of methane (one doesn’t drill wells where there is no methane). Comparing water methane levels before and after fracking seems to be the only way to prove that fracking is causing the increased water methane levels.
Alan Bomberger, via e-mail