Steingraber On Cancer Risk in Texas's Fracking Zone


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This is a response from Sandra Steingraber, distinguished scholar in residence at Ithaca College, to the Dot Earth post “More on Gas Drilling, Peer Review and Public Health,” in which I questioned the definitiveness of language she used in a letter to New York Gov. Andrew M. Cuomo to describe cancer trends in the Barnett Shale area of Texas.
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  • Thank you Sandra. Your book, the film and all your writings have been invaluable contributions to my efforts as a teacher. Please know that your work is deeply appreciated.
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Steingraber On Cancer Risk in Texas's Fracking Zone

  1. 1. This is a response from Sandra Steingraber, distinguished scholar in residence at IthacaCollege, to the Dot Earth post “More on Gas Drilling, Peer Review and Public Health,”in which I questioned the definitiveness of language she used in a letter to New YorkGov. Andrew M. Cuomo to describe cancer trends in the Barnett Shale area of Texas:Josh Fox makes two points about breast cancer in The Sky in Pink. One is about trends ofbreast cancer incidence within areas of north Texas with intense drilling and frackingoperations. The other is about pink drill rigs.The first was seized upon by AP reporter in an attempt to claim that Fox hadexaggerated. Journalist Tom Wilber and Dot Earth then continued that line of inquiry.I’ll come back to the Texas cancer registry data in a moment—along my own reference toit in last December’s letter to Governor Cuomo about the cancer risks of fracking.I want to talk first about that pink rig because it’s been overlooked so far in thisconversation and because its existence—as both symbol and fact—helps explain whyenvironmental explanations for human cancers are often held to a different standard thanthe “traditional” risk factors: diet, exercise, genetic susceptibility. (More uncertaintysurrounds the role of animal fat in contributing to breast cancer than exposure to airpollution, for example. Nevertheless, cancer control agencies freely give dietary adviceto women. They are seldom accused of exaggerating the evidence or crying “fire” in acrowded theater when they do so.)Polluting industries not only fund research projects that serve to downplay the health andenvironmental impacts of their actions, as we have been discussing here, they alsocontribute money to charities or otherwise associate themselves with charities, includingbreast cancer groups, (whose iconic color is pink). In turn, the industries receive goodpublicity.Along the way, they also influence public opinion about the causes of cancer anddiscourage efforts to prevent cancer by, say, eliminating exposures to carcinogens. Therecent book and documentary film,Pink Ribbons, Inc. explores this phenomenon closely,as does the watchdog organization of the breast cancer movement, Breast Cancer Action,as part of its “Think Before You Pink” campaign. [Full disclosure: I have served as ascience advisor for this group.]Ergo, fracking for the cure.Indeed, the Pennsylvania Breast Cancer Coalition counts Chesapeake Energy, a top oiland gas company, as a corporatepartner. These kinds of alliances—symbolized by the pink drill rig—are the bigger story, it seems tome, and yet they are not making headlines in the Associated Press. Meanwhile, afilmmaker’s statements about puzzling breast cancer trends in Texas are.
  2. 2. As you note, I wrote about these same trends in a fully referenced letter to GovernorCuomo last December. I stand by my words.I also wrote about many other lines of evidence, and this is important. In the absence ofconducting controlled exposure experiments on human beings—which would beunethical--researchers have to assemble the pieces of evidence available to us.Patterns in cancer registry data over time and across space provide one line ofevidence. Combined with other lines of evidence, they can offer powerful clues. Lookingat patterns in breast cancer incidence data before and after 2002, for example, allowed usto conclude—in the context of other data—that hormone replacement therapy aftermenopause contributes to breast cancer.Whenever epidemiologists see an unusual pattern of disease incidence in a given area,especially one like breast cancer that has established links to environmental exposure, thenext three questions are to ask are these--1) Are there other diseases with environmental links whose incidence rates are alsodifferent in this area?2) Is there biological plausibility for an environmental explanation?3) Is there anything demographically different about the women who live there thatmight explain the unusual patterns (ethnicity, reproductive history, breastfeeding rates,access to mammograms)?In the case of breast cancer in the Barnett Shale area of Texas, the answers to the first twoquestions above, although incomplete, seem to be yes. Consider:Childhood asthma is Tarrant County is more than double the national average;researchers from Baylor University are now investigating., in Colorado, a study from the Colorado School of Public Health found thatdrilling and fracking operations release benzene into air at levels known to elevate cancerrisk. is important because we know that benzene exposure has demonstrable links tobreast cancer. Benzene is specifically highlighted in the 2010 President’s Cancer PanelReport: Benzene’s role as a possible breast carcinogen wasalso highlighted in the recent Institute of Medicinereport: Benzene’s association with breast cancer aredescribed in the science review by researchers at the Silent Spring
  3. 3. Institute: and BrodyJG, Moysich KB, Humblet O, Attfield KR, Beehler GP, Rudely RA. Environmentalpollutants and breast cancer: epidemiologic studies. Cancer. 2007, 109 (12 Suppl):2667-711. Benzene’s links to breast cancer were also reviewed by the California Breast CancerResearch Program’s 2007 report, Identifying Gaps in Breast Cancer Research:Addressing Disparities and the Roles of the Physical and Social Environment, which Ihelped to edit: also know—from studies conducted in Long Island—that breast cancer risk isassociated with industrial and traffic-related air pollution: Lewis-Michl EL, Melius JM,Kallenbach LR, Ju CL, Talbot TO, Orr MF, Lauridsen PE. Breast cancer risk andresidence near industry or traffic in Nassau and Suffolk Counties, Long Island, NewYork. Arch Environ Health. 1996, 51(4):255-65.We know, from EPA data, that north Texas has at least two census tracts in which thecancer risk from toxic air pollution is significantlyhigh: we know that 35 different air pollutants act as breast carcinogens in animal studies:Rudel RA, Attfield KR, Schifano JN, Brody JG. Chemicals causing mammary glandtumors in animals signal new directions for epidemiology, chemicals testing, and riskassessment for breast cancer prevention. Cancer. 2007, 109(S12):2635-66.In conclusion, there are plenty of biological reasons for asking whether air pollution andother stressors from drilling and fracking operations in the Barnett Shale area of Texasmight be playing a role in the story of breast cancer there.With all the above as backdrop, here is what I notice about breast cancer rates when Ilook at the interactive county maps and rates for invasive and in situ breast cancer for thestate (, there has been a slow, statewide decrease in breast cancer incidence. However,the area that includes Denton, Texas appears not to follow this pattern. In fact, for singleyears, beginning in 2005, the rate increases. Moreover, along with the Houston area, thearea that includes Denton leads the state.Is mammography use in this region lower than Texas statewide? Well, the diagnosis ofvery early-stage breast cancer (in situ cancer) appears at least as high in the DentonCounty area than it is in the state as a whole. (High rates of in situ breast cancer are oftenindicators of high rates of compliance with mammogram screening guidelines.)In conclusion, I feel that I am on firm ground—and so is Josh Fox—in saying that thebreast cancer incidence in particular areas of Texas look different than the rest of the stateand that these areas happen to be where fracking goes on intensely.Given that drilling and fracking operations involve releases of known and suspected
  4. 4. breast carcinogens--and benzene is one--it is reasonable, and morally right, to ask iffracking might be involved with the creation of these patterns.Until the answers are in, benefit of the doubt goes to breasts, not to the chemicals thatcause cancer in breasts. And the burden of proof belongs on the shoulders of the gasindustry to demonstrate safety, not on the backs of women, who would have to suffer anddie order to demonstrate without a doubt that fracking causes breast cancer.When public health is at stake, the trigger for action is indication of harm, not proof ofharm.Stop fracking. Do the research. Investigate these patterns.