Is Fracking Safe?

It May Depend on What You Mean By "Fracking"

A new study by Thomas Darrah of Duke University and four colleagues, published in the Proceedings of the National Academcy of Sciences, suggests that there has been significant contamination of the ground water from natural gas drilling in Pennsylvania and Texas, but this contamination is not due to the process of hydraulic fracturing itself. Rather it is caused by leakage of methane, the primary ingredient in natural gas, and other chemicals near the surface due to faulty construction of the well.

The researchers took 133 water samples from drinking water wells—113 of them from along the Marcellus Shale in Pennsylvania and 20 from the Barnett Shale in Texas. Through chemical analysis, they were able to tell whether each sample was contaminated, and if so, from where the contimation had come. I'm not knowledgeable enough in chemistry to understand the testing that was done, so I rely on the fact that this was a peer-reviewed journal.

They found eight clusters of contaminated wells—seven in Pennsylvania and one in Texas. The cluster in Texas consisted of five of the twenty samples they took. They don't say how many samples were included in the seven Pennsylvania clusters. From eyeballing their charts, it looks like about 20-25% of their samples were contaminated. However, the wells were not randomly selected. The researchers had focused on areas where contamination was suspected.

The chemical analysis indicated that four of the eight clusters were due to leakage around the cement used to seal the outside of the well, three were due corroded or poorly joined steel tubing used to drill into the ground, and the last was due to “underground mechanical well failure.”

Diagram by Howarth and Engelder (2011)

In hydraulic fracturing, or fracking, fracking fluid is forced into the shale at high pressure in order to release the natural gas contained in it. The concern is that fracking might create breaks in the undreground rock formations, through which either natural gas or fracking fluid might leak upward and contaminate drinking water. None of the contamination came from far enough below the surface to indicate that this type of contamination had occurred.

Unlike last week's study of the correlation between fracking sites and health problems, this study received generous coverage by the corporate media. The general spin seemed to be that “fracking is safe.” The Pittsburgh Post-Gazette ran a McClatchy article about the study on the front page. Two days later, they reprinted a Bloomsberg op-ed entitled “Fracking is not the threat.” The threat, it seems, is drilling company carelessness, which can be avoided through government regulations, regular inspections, and fines for poor performance.

The coverage is superficial in at least two respects. First, while there is no evidence that fracking in the narrow sense--that is, hydraulic fracturing, per se--has caused contamination, fracking in a broader sense--the fracking boom--is certainly responsible for ground water contamination. Regulation and oversight of the drilling industry will not be accomplished easily, especially in a state like Pennsylvania, where the state government is a wholly-owned subsidiary of the natural gas industry.

Secondly, the absence of evidence of leakage due to fracking, per se, does not necessarily mean that there is none and the process is safe. Methane and fracking fluid from deep in the shale may simply take a longer time to reach the surface than chemicals that leak from at or near the surface. Maybe decades. The Darrah study may simply have been done too soon.

Meanwhile, there is accumulating evidence of another problem caused by natural gas drilling. A new report published in the Bulletin of the Siesmological Society of America shows a significant increase in earthquakes in the Raton Basin of Colorado and New Mexico since 2001. Fracking began there in 1999. As in previous studies, most of the earthquakes are located within 5 kilometers of waste water injection wells, rather than near sites where hydraulic fracturing has taken place. I guess that means that fracking is “safe,” but it doesn't solve the problem of what to do with the waste water.

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Fracking and Public Health, Part 1

Fracking and Public Health, Part 2

La Terra Trema

Fracking and Public Health, Part 2

The Coverage

Please read part 1 about the Rabinowitz survey of fracking and health.

With the exception of USA Today, the response of the corporate media to the Rabinowitz study has been a collective yawn.

Since Washington County is part of the area served by the Pittsburgh Post-Gazette, one might expect the survey to be front-page news. On the contrary, the study was buried in a short article on page 4 of the local section, with what seems like a deliberately uninformative headline, “Study looks at gas wells, health.” Three of its nine paragraphs were devoted to rebuttal from Travis Windle, a spokesman for the Marcellus Shale Coalition, an industry group.

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In an unusually harsh attack on the integrity of the researchers, Mr. Windle stated, "This study, done in partnership with a local activist group, was designed to put selective and unproven data behind a predetermined and biased narrative." The activist group is presumably the Southwest Pennsylvania Environmental Health Project, which is opposed to fracking. They are credited with assistance with the survey; specifically: "The survey was pre-tested with focus groups in the study area in collaboration with a community-based group and revised to ensure comprehensibility of questions." If this is all they did, they played only a limited role in the study.

Pittsburgh's avowedly right wing newspaper, the Tribune-Review, offered an unusual take on the Rabinowitz study. First of all, they claim that this study is balanced by a “confllicting” 2014 study by Penn State geologist Terry Engelder and colleagues. This study found no evidence that fracking fluids, injected deep underground into the Marcellus shale, were migrating toward the surface and contaminating the ground water. Rather than conflicting, the two studies are actually irrelevant. Rabinowitz attributed the symptoms he discovered to air pollution, pollution of ground water from fluids leaking from around the drilling site, and stress. Migration of deep underground fluids, if it occurs, is presumably a problem for future generations to deal with, long after the drilling companies have taken their money and run.

The Tribune-Review also suggested that both studies are biased due to their source of funding. The Engelder study was supported by the Marcellus Shale Coalition and included an employee of Shell International as one of its co-authors. The primary supporter of the Rabinowitz study was the non-profit Heinz Foundation. The Heinz Foundation underwent a turnover of its executive staff beginning in August 2013, which is widely interpreted as a shift toward opposition to fracking. Previously, Heinz had been a member of the Center for Sustainable Shale Development, a coalition of environmental and industry groups that was supposed to establish voluntary safety rules for drilling. However, the Rabinowitz study was completed in 2012, while Heinz was still friendly with the drilling industry.

It's clear that we need an improved vocabulary for talking about real or imagined conflicts of interest in research, one which, at a minimum, distinguishes between financial and ideological conflicts of interest. If your research is supported by a for-profit corporation and its results are contrary to corporate interests, two consequences are likely. First, the research results will never be made public, and second, you will never again receive financial support from that corporation. Those outcomes are unlikely when your research is supported by a non-profit foundation.

The Tribune-Review seeks to expand the category of conflicts of interest to include those cases when the researchers or their sponsors have an opinion about the research topic. But this is unrealistic, since investigators almost always have opinions about their research, opinions which often explain why they were interested in the topic in the first place. Even when the research topic is completely non-political, scientists are often professionally committed to their research hypotheses. Good research design ensures that the researchers' expectations, and those of their financial supporters, do not influence the results.

I can't comment on the design of the Engelder study because I lack expertise in geoscience. I described the Rabinowitz study in some detail because it seems to me that the authors have done a good job, under the circumstances, of minimizing researcher bias and evaluating alternative explanations. Right now, the best advice to people on both sides of the issue is replicate, replicate, replicate. For example, studies of fracking and health are in progress at the Geisinger Health Center in central Pennsylvania. Ultimately, whether researchers have successfully eliminated bias is an empirical question. If studies are replicated often enough, it should be possible to determine through systematic reviews whether researchers with different sources of funding have obtained inconsistent results.

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Fracking and Public Health, Part 1

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Motivated Reasoning

Fracking and Public Health, Part 1

An Important First Study is Published

Corporations that engage in mining and manufacturing are extremely fortunate that Americans cannot be randomly assigned to places of residence. This prevents researchers from doing true experiments--that is, randomly assigning people to experimental and control groups to study the effects of air, water and soil pollution on public health. As a result, when epidemiologists, who study the spatial distribution of health and illness, find evidence of illness concentrated in the vicinity of sources of industrial pollution, it its always possible for corporations to claim that something else—known or unknown—is responsible. Correlation does not mean causation.

On Wednesday, what is to my knowledge the largest scientific study relating proximity to natural gas wells to human health, conducted by a team led by Peter Rabinowitz of the Yale School of Medicine, was released online by the peer-reviewed journal Environmental Health Perspectives. Previous evidence of an association between natural gas drilling and illness had come either from case studies or convenience—that is, nonrandom—samples.

Photo by Ruhrfisch

The study was done in Washington County, south of Pittsburgh, which had 624 active natural gas wells, 95% of which utilized hydraulic fracturing. A set of 38 contiguous rural communities were selected for study, to avoid urban areas unlikely to have ground-fed wells. Within these communities, 760 geographic points were randomly chosen and the nearest residence was selected for study. Some sites were excluded due to duplication, because there were no homes nearby, or because the house did not have a ground-fed well. This left 255 eligible households, 180 (71%) of which agreed to participate. Forty-seven households refused to participate, and researchers were unable to contact residents of the remaining homes.

Participants were interviewed in their homes in the summer of 2012 by trained survey researchers who followed a prepared script. The survey made no reference to natural gas drilling. Researchers were unaware of the home's proximity to the nearest gas well. (Of course, this precaution failed if a drilling rig was visible from the front porch.) An adult member of the household was asked questions assessing the health status and symptoms of each member of the household—a total of 492 people. Participants were paid $25. Participating households were divided into those within 1 kilometer (.6 miles) of a natural gas drilling site, those between 1 and 2 km, and those more than 2 km from the nearest site.

Respondents were asked about six types of health problems: dermal, upper respiratory, lower respiratory, gastrointestinal, neurological and cardiovascular. The following variables were statistically controlled: age, gender, education, occupation, the presence of smokers or pets in the home, and awareness of nearby environmental hazards. Statistically significant results were obtained in two of the six health areas, dermal and upper respiratory.

• Upper respiratory symptoms, such as coughing, itchy eyes and nosebleeds, were reported by 39% of those living within a km of a drilling site but only 18% of those who lived more than 2 km away. Both the near and intermediate groups reported significantly more upper respiratory symptoms than the far group.
• The number of people suffering from dermal problems was smaller, but the association was stronger. Thirteen percent of those living nearest to a gas well suffered from skin problems, such as rashes, itching and burning, but only 3% of those living the farthest away. The near group reported significantly more dermal symptoms than the far group.

The authors do not claim that their data show a causal relationship between drilling and health problems. However, they speculate that, if natural gas drilling is responsible for these skin and respiratory issues, it could have happened through three pathways: (1) pollution of ground water, including the water in their wells; (2) air pollution from the drilling site; and (3) stress due proximity to a drilling site. Noise is a particularly potent stressor. Supporting the stress hypothesis is the fact that those who were aware of nearby environmental hazards reported more skin and respiratory symptoms, although the relationship between proximity and symptoms was still significant when the effect of awareness was statistically removed.

Whenever a relationship between industrial pollution and illness is found, the most likely alternative explanation is the indirect involvement of social class. Locations that are close to sources of pollution are usually undesirable places to live. Property values are lower and people living nearby have lower incomes. We know that, for a variety of reasons, lower income Americans are in poorer health. However, this explanation is weakened somewhat by the fact that almost all the natural gas wells in Washington County were drilled within the last 5-6 years. This allowed less time for migration to occur and for pockets of poverty to form around the drilling sites.

Because the researchers relied on self-report data, it's possible that people living close to drilling sites exaggerated their symptoms—although they might also have had reasons to minimize them. The fact that the results were still strong when awareness of environmental hazards was controlled argues against this interpretation. Future researchers should consider conducting actual medical examinations of the participants. This would of course be much more expensive and logistically challenging.

The 71% completion rate is well above average for surveys. However, it might be argued that people experiencing illnesses that they attributed to local drilling were more anxious to tell their story, and that this contributed to an overestimation of the percentage with health problems. However, the refusal rate did not vary significantly with distance from the nearest drilling site.

The health problems detected in the study were among the least serious included in the survey. Since most of those surveyed had only been living near a gas well for a short time, the authors say they were not surprised that diseases with longer latencies, such as heart conditions or cancers, were not yet associated with proximity to a drilling site.

The research was supported by a grant from Pittsburgh's Heinz Foundation, along with four other non-profit sources. The authors thanked the Southwest Pennsylvania Environmental Health Project for “assistance with the community survey.” They conclude by calling for further research, including “longitudinal assessment of the health of individuals living in proximity to natural gas drilling activities, medical confirmation of health conditions, and more precise assessment of contiminant exposures.”

To be continued in Part 2.

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La Terra Trema

Reefer Madness Revisited

Chronic pain is a major problem in this country. To combat it, doctors are prescribing—some would say overprescribing—opioids such as Vicodin and OxyContin. Americans consume about 90% of the world's supply of these dangerous drugs. According to the Centers for Disease Control, opioid overdose deaths have increased from 4,030 in 1999 to 16, 651 in 2010. That's an average of 46 deaths per day, more than heroin and cocaine combined. Sixty percent of these folks have a legitimate doctor's prescription. If only someone could come up with a safer way of treating pain. . . . .

Marijuana has been shown to be effective in treating chronic pain. A survey of medical marijuana users in Canada found that 68% of them used it as a substitute for prescription drugs. The three main reasons given were fewer withdrawal symptoms, fewer side effects, and better symptom management. Marijuana can also be effectively combined with opioids to allow patients to use lower doses of opioids. If you can locate someone who has died from a marijuana overdose, you have a scoop. In July, New York became the twenty-third state to legalize marijuana for medical use.

Marcus Bachhuber and his colleagues published a new study of the effects of marijuana legalization on opiate deaths in the Journal of the American Medical Association this week. It's not a controlled experiment; it's a before-after comparison group design. While there is some ambiguity about how to interpret it, the study has a number of important strengths.

The authors counted opioid deaths on death certificates from all 50 states between 1999 and 2010. By 1999, three states (California, Oregon and Washington) had already legalized medical marijuana. Another ten states legalized it while the study was in progress. (The remaining ten states changed their laws after 2010.) The death rates from opioids were compared between those states that had legalized medical marijuana (the marijuana states) and those that had not (the comparison states). They also compared death rates within the marijuana states from before to after legalization. The design statistically controlled two variables that are known to affect the opioid death rate, the unemployment rate and state policies regulating prescription drugs.

• Those states in which medical marijuana was legal at the time had a 24.8% lower mean annual opioid mortality rate than the comparison states. The marijuana states had 1729 fewer death than would otherwise be expected in 2010 alone. The results were unchanged when suspected suicides were eliminated.
• In the ten states that legalized marijuana between 1999 and 2010, the drop in the death rate from opioids coincided with the change in the law. It took a couple of years for the full effect of the legal change to be realized. On average, the death rate dropped 20% in the first year, 25% in the second, and peaked at 33% in the fifth and sixth years.
  
  

In searching for possible hidden confounds, our attention is naturally draw toward possible differences between the marijuana and comparison states that might have affected overdose deaths. There is a possible selection bias. The marijuana states are more progressive, and it's possible, but not obvious, that political liberalism might reduce painkiller deaths in other ways. However, when the death rates are compared from before to after the legalization, the marijuana states become their own controls.

It is important to note that in order to explain the results, a potential confound would not only have to be more prevalent in the marijuana states, it would also have to have occurred at about the time legalization took effect. One of the strengths of this study is that the drop in deaths coincides with the onset of legalization even though the law changed at different times in different states. This makes it less plausible that historical events affecting several states simultaneously could account for the results.

Almost all news reports about this study quote drug experts who urge caution when drawing conclusions from the study, although they usually don't specify what they think is wrong with it. One expert, Dr. Andrew Kolodny, is quoted in Newsweek as suggesting that states that legalized medical marijuana might also impose more restrictions on the prescribing of painkillers, apparently not realizing that the authors had anticipated this possibility and found that prescription monitoring laws were not associated with lower overdose death rates. (The reporter did not correct his error, allowing readers to assume that he had made a valid point.) Of course, most articles also contain the obligatory vague words of warning about the alleged dangers of the devil's weed.

The study makes a fairly strong case for the immediate legalization of medical marijuana at the federal level and in the remaining states. Why is medical marijuana still illegal? As the Bachhuber study suggests, medical marijuana is a serious threat to the profits of pharmaceutical companies. Given the opportunity, chronic pain sufferers are likely to substitute marijuana for more expensive and dangerous prescription drugs. Journalist Lee Fang points out that the groups leading the fight against relaxing marijuana laws, such as the Partnership for Drug-Free Kids, receive a large portion of their funding from the pharmaceutical companies that market analgesic opioides. Several leading anti-marijuana academic experts also serve as paid consultants to big pharma. Here is Fang being interviewed by Chris Hayes.

As usual, we can say (this time, with enthusiasm) that more research is needed. The good news is that the Drug Enforcement Administration has increased its annual allotment of cannabis for clinical research from 21 kilograms to 650 kilograms—still too little—in response to demand from investigators.

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