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. More at http://dotearth.blogs.nytimes.com/tag/fracking

1. 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:
Josh Fox makes two points about breast cancer in The Sky in Pink. One is about trends of
breast cancer incidence within areas of north Texas with intense drilling and fracking
operations. The other is about pink drill rigs.
The first was seized upon by AP reporter in an attempt to claim that Fox had
exaggerated. 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 to
it 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 this
conversation and because its existence—as both symbol and fact—helps explain why
environmental explanations for human cancers are often held to a different standard than
the “traditional” risk factors: diet, exercise, genetic susceptibility. (More uncertainty
surrounds the role of animal fat in contributing to breast cancer than exposure to air
pollution, for example. Nevertheless, cancer control agencies freely give dietary advice
to women. They are seldom accused of exaggerating the evidence or crying “fire” in a
crowded theater when they do so.)
Polluting industries not only fund research projects that serve to downplay the health and
environmental impacts of their actions, as we have been discussing here, they also
contribute money to charities or otherwise associate themselves with charities, including
breast cancer groups, (whose iconic color is pink). In turn, the industries receive good
publicity.
Along the way, they also influence public opinion about the causes of cancer and
discourage efforts to prevent cancer by, say, eliminating exposures to carcinogens. The
recent 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 a
science advisor for this group.]
Ergo, fracking for the cure.
Indeed, the Pennsylvania Breast Cancer Coalition counts Chesapeake Energy, a top oil
and gas company, as a corporate
partner. http://lancasteronline.com/article/local/475191_Partnership-challenged.html The
se kinds of alliances—symbolized by the pink drill rig—are the bigger story, it seems to
me, and yet they are not making headlines in the Associated Press. Meanwhile, a
filmmaker’s statements about puzzling breast cancer trends in Texas are.

2. As you note, I wrote about these same trends in a fully referenced letter to Governor
Cuomo last December. I stand by my words.
I also wrote about many other lines of evidence, and this is important. In the absence of
conducting controlled exposure experiments on human beings—which would be
unethical--researchers have to assemble the pieces of evidence available to us.
Patterns in cancer registry data over time and across space provide one line of
evidence. Combined with other lines of evidence, they can offer powerful clues. Looking
at patterns in breast cancer incidence data before and after 2002, for example, allowed us
to conclude—in the context of other data—that hormone replacement therapy after
menopause 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, the
next three questions are to ask are these--
1) Are there other diseases with environmental links whose incidence rates are also
different in this area?
2) Is there biological plausibility for an environmental explanation?
3) Is there anything demographically different about the women who live there that
might 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 two
questions 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.
http://www.baylor.edu/mediacommunications/news.php?action=story&story=98474
Meanwhile, in Colorado, a study from the Colorado School of Public Health found that
drilling and fracking operations release benzene into air at levels known to elevate cancer
risk. http://www.erierising.com/human-health-risk-assessment-of-air-emissions-from-
development-of-unconventional-natural-gas-resources/
This is important because we know that benzene exposure has demonstrable links to
breast cancer. Benzene is specifically highlighted in the 2010 President’s Cancer Panel
Report: http://deainfo.nci.nih.gov/advisory/pcp/annualreports/pcp08-
09rpt/PCP_Report_08-09_508.pdf. Benzene’s role as a possible breast carcinogen was
also highlighted in the recent Institute of Medicine
report: http://www.iom.edu/Reports/2011/Breast-Cancer-and-the-Environment-A-Life-
Course-Approach/Press-Release.aspx. Benzene’s association with breast cancer are
described in the science review by researchers at the Silent Spring

3. Institute: http://sciencereview.silentspring.org/mamm_detail.cfm?cid=71-43-2 and Brody
JG, Moysich KB, Humblet O, Attfield KR, Beehler GP, Rudely RA. Environmental
pollutants 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 Cancer
Research Program’s 2007 report, Identifying Gaps in Breast Cancer Research:
Addressing Disparities and the Roles of the Physical and Social Environment, which I
helped to edit: http://www.cbcrp.org/sri/reports/identifyinggaps/GAPS_full.pdf
We also know—from studies conducted in Long Island—that breast cancer risk is
associated 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 and
residence near industry or traffic in Nassau and Suffolk Counties, Long Island, New
York. Arch Environ Health. 1996, 51(4):255-65.
We know, from EPA data, that north Texas has at least two census tracts in which the
cancer risk from toxic air pollution is significantly
high: http://www.epa.gov/ttn/atw/nata2002/risksum.html.
And 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 gland
tumors in animals signal new directions for epidemiology, chemicals testing, and risk
assessment for breast cancer prevention. Cancer. 2007, 109(S12):2635-66.
In conclusion, there are plenty of biological reasons for asking whether air pollution and
other stressors from drilling and fracking operations in the Barnett Shale area of Texas
might 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 I
look at the interactive county maps and rates for invasive and in situ breast cancer for the
state (http://www.cancer-rates.info/tx/index.php)--
Overall, 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 single
years, beginning in 2005, the rate increases. Moreover, along with the Houston area, the
area that includes Denton leads the state.
Is mammography use in this region lower than Texas statewide? Well, the diagnosis of
very early-stage breast cancer (in situ cancer) appears at least as high in the Denton
County area than it is in the state as a whole. (High rates of in situ breast cancer are often
indicators 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 the
breast cancer incidence in particular areas of Texas look different than the rest of the state
and that these areas happen to be where fracking goes on intensely.
Given that drilling and fracking operations involve releases of known and suspected

4. breast carcinogens--and benzene is one--it is reasonable, and morally right, to ask if
fracking 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 that
cause cancer in breasts. And the burden of proof belongs on the shoulders of the gas
industry to demonstrate safety, not on the backs of women, who would have to suffer and
die 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 of
harm.
Stop fracking. Do the research. Investigate these patterns.