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Dimock in the News Again: Unanswered Questions Keep Bubbling Up.

Kate Sinding

Posted October 4, 2012

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Questions keep coming to the surface as details of EPA’s investigation of Dimock water wells are continuing to be reviewed.  A few weeks ago, I blogged about the the Agency for Toxic Substances and Disease Registry’s (a federal health agency) still active investigation into the potential health risks from using Dimock water, despite EPA’s assessment that Dimock water was “safe.”  And this past week, recent articles in the Scranton Times Tribune (see here and here) and Bloomberg News, have once again shown a spotlight on some of the lingering questions about Dimock water.

In short, here are the ongoing concerns:


No one questions that there is methane in Dimock water.  Out of the fifty-nine water wells in Dimock that EPA tested for contaminants, twenty had more than 7 milligrams of methane per liter, the actionable threshold necessary for mitigation under Pennsylvania law.  Fifteen of those homes had more than double that amount, five of which had more than four times the PA threshold level, which is also the point at which methane begins to escape from water and create a risk of explosion if not properly vented.

Regardless, the Cabot Oil and Gas Corporation argues that this contamination is naturally occurring and not a result of its fracking operations in Dimock—a claim which is in direct contradiction to the complaints of residents and the official findings of the Pennsylvania Department of Environmental Protection.  Recent analysis of EPA’s isotopic testing (a form of chemical “finger printing”) of the methane gas found in Dimock drinking water also undercuts this claim. 

While the results are not determinative, Robert Jackson, an environmental scientist at Duke University who has also conducted research on the correlation of methane in water supplies with fracking, has said that the chemical signature of the gas studied by EPA suggests that it is likely from one of two sources related to gas drilling: (1) gas from middle rock formations that travelled up in the space between the steel drilling casings and the drilled wells, or (2) gas from the Marcellus itself that has leaked out through a perforated casing.


EPA declared Dimock drinking water “safe” despite results showing high levels of methane that , in some cases, was beyond the level at which methane escapes from water, creating a potential explosion risk.  Review of EPA emails obtained from a Freedom of Information Act Request by Scranton Times Tribune writer Laura Legere shows that EPA may have also found other contaminants of concern that the agency apparently did not follow up on.

In one water well, EPA found unsafe levels of arsenic, but when officials approached the affected resident, they learned that Cabot had reportedly been tipped off about the testing results and had begun delivering temporary drinking water two days prior.  EPA allowed Cabot to keep delivering water at the resident’s request, but did not attempt to determine the source of the arsenic or to require Cabot to provide long-term treatment or replacement of the water.

Additionally, EPA originally selected fifteen homes for a second round of sampling because “one or more contaminants were found at the tap at concentrations above the trigger level established for that contaminant.”  In the end, however, EPA headquarters only approved re-sampling at four homes—and even then, only for the “limited list” of substances “found in the first round of EPA sampling.”


EPA emails also reveal that the agency was aware of allegations that the company used diesel fuel to frack at least two early Dimock wells.  Because of a 2005 exemption, gas wells are not regulated under the federal Safe Drinking Water Act - unless they use diesel.

EPA evidently never asked Cabot if it used diesel to frack any of its wells given that the agency was still working on its own permitting guidance for using diesel fuel in oil and gas wells at the time.  Nor, apparently, has EPA asked since, and Cabot has made no statement about whether it used diesel in its wells.

As more information about Dimock continues to come to light, it seems evident that industry’s contentions that the regulatory agencies have “exonerated” gas drilling and/or fracking as the cause of serious contamination problems in Dimock were premature and misplaced.  To the contrary, it appears more clear than ever before that (1) the methane contamination in Dimock was, as PADEP initially concluded, clearly caused by Cabot’s drilling activities, and (2) questions about  the “safety” of Dimock’s water persist.

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Michael BerndtsonOct 4 2012 12:42 PM

From your paragraph regarding two potential sources as hypothesized by Robert Jackson:
"(1) gas from middle rock formations that travelled up in the space between the steel drilling casings and the drilled wells, or (2) gas from the Marcellus itself that has leaked out through a perforated casing."

Do you know if anyone is guessing if Marcellus shale methane is entering the PA groundwater from vertical or "rogue" fractures extending from the horizontal bore upward. The other two possible scenarios are engineered sources and can possibly be mitigated by well plugging upon abandonment. The scenario I threw out there, while engineered via fractures, may be impossible to mitigate. I'm guessing that engineered hydraulic fractures can't be plugged. The rogue fracture issue has been somewhat ignored in the US.

A University in England did a paper study using available geophysical data post fracking and is summarized in the following source: I can't find any paper, laboratory or field studies on this issue for US shale plays done rigorously and explicitly for groundwater protection.

It would take a fair amount of geophysical subsurface surveying to determine presence of rogue fractures. But still cheaper then environmental forensic studies and legal squabbling.

Anyway, great work. What's going on in PA may happen in NY and my home state of Illinois with the New Albany formation.

Mike Berndtson

DoryOct 4 2012 02:07 PM

Per Terry Engelder, Professor of GeoScience, Penn State Univeristy

"While it's true that methane seepage into ground water is a natural phemomenon throughout much of Pennsylvania, drilling activity is known to accelerate this process."

"I find it disingenuous that Cabot can deny culpabilty, when other industry leaders have recognized the problem and are proactively working with Penn State to solve it."

Dan RaichelOct 4 2012 03:24 PM

Hi Michael,

My name is Dan Raichel. I’m a project attorney at NRDC who works with Kate on community issues related to fracking. I don’t know of anyone else that has done work on “rogue fractures” per se. But you can look at the recent study by Tom Myers, which used computer modeling to show that transport of underground waste fluids from shale formations up to underground aquifers is hydrologically possible.

James Singmaster,III, Ph.D.Oct 11 2012 03:18 PM

We need redirection concerning how to get energy.WHY are we wasting so much energy and also money as well in our biowastes that we mishandle leading to various environmental problems worse than fracking causes?? This includes having synthetic female hormones showing up in some drinking water samples causing EPA in spring 2010 to put limits on several. I would suggest that's just the tip of the iceberg and what does EPA DO IF LIMITS GET EXCEEDED?
Those biowastes including separated sewage solids are an already harvested forever biofuel supply line taking no land, water or fertilizer from needed food production. A process called pyrolysis that is used to make charcoal can be applied to biowastes to "remake coal" to bury or use as a soil amendment and to get an expelled gaseous mix much like oil drilling venting releases that often just get burned off. That mix can be refined to get fuel renewably or chemicals to make drugs, detergents without oil thereby cutting some into foreign oil dependence. The much bigger benefit comes from the destroying of germs, toxics and drugs in the biowastes so that no problems with those hazards escaping from biowastes into the environment can occur. Several percent of our GNP may get "wasted" in doing all the EPA actions presently required for handling wastes and maintaining dump sites with those waste hazards present. An added problem can develop in biowaste dumps with microbes altering non-toxics into toxics and with dangerous microbes finding good conditions for their growth.
I urge NRDC to switch gears and call for actions necessary to keep our children from being buried by our neglected ever-mounting messes of organic wastes. Get attention to using the pyrolysis process to handle our biowastes especially to make them the key resource for a sustainable future. Dr. J. Singmaster, III, Environmental Chemist, Ret.

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