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Societal implications of a new occupational and environmental cancer study

By Michael Gilbertson PhD

In November 2012, a group of twelve researchers comprised of occupational health professionals, scientists, epidemiologists, statisticians and cancer doctors, published a paper on the occupational and environmental risk factors associated with breast cancer in the Windsor, Essex and Chatham, Kent areas of southwestern Ontario.(1) The paper documented that in jobs with high exposures to mammary carcinogens and endocrine disruptors there was a 50% increase in the risk. Specifically for premenopausal women in certain industries, such as automotive plastics manufacturing and canning there was a five-fold increased risk. With the help of international environmental media organizations, the paper generated more than 350 newspaper stories in the first month and within a year and a half, it had been downloaded from the journal website more than 27,500 times. The journal editors praised it as one of their most successful articles and the American Public Health Association recognized the primary authors, Dr James Brophy and Dr Margaret Keith with an award for one of the three best papers on occupational health published in 2012.

To understand what the paper represented we need to recall the troubled history of occupational cancer research in North America. For example, though Dr Wilhelm Hueper was Director of the Environmental Cancer Department of the National Cancer Institute from 1948 -1964, the US Surgeon General ordered him to “cease all NCI epidemiological work on occupational cancer” because it was inciting union pressure on Congress to protect workers through legislation.(2) With the late-1960s activism of the coalesced social movements and the subsequent wave of environmentalism, official predictions were that between 20 and 40% of future cancers would be caused by environmental and occupational exposures.(3)

In 1979, Dr Samuel Epstein published an exposé of what he referred to as the Cancer Establishment in his book The Politics of Cancer and noted how occupational cancer was seriously understudied and incidence underestimated.(4) With the Reagan era, the new official estimates were revised downwards so that between 2 and 4% of cancers were thought to be of occupational and environmental origin and that resources should go into individual risk factors, cancer biology and finding the cure and not into environmental and occupational risk factors. Funding for occupational epidemiology declined, particularly for research on risk factors(5) for breast cancer in women. Brophy and Keith’s new paper represents a challenge to the revised fraction of cancer attributable to environmental and occupational exposures and thereby to the cancer funding allocations that have prevailed for the past three decades.

The causes of breast cancer are highly contested. The ways of understanding these struggles have been analysed by the sociologist Dr Phil Brown and colleagues.(6) First, there are questions about who is a legitimate researcher. In the early 1990s, groups of breast cancer activists in Long Island, Cape Cod and San Francisco decided that the high incidences of breast cancer in their regions were being officially neglected. The Long Island and Cape Cod lay groups secured funding to initiate various aspects of breast cancer research and the San Francisco group forced the cancer research funding agencies to accept lay persons onto their review committees. Brophy and Keith, as occupational health advocates, initiated their research by surrounding themselves with highly qualified researchers from different specialties. More particularly, they conducted focus groups to ask the workers what chemicals they were exposed to and to describe the working conditions inside the factories, thereby including workers as participatory action researchers.

The second axis of Dr Phil Brown’s analysis concerned what risk factors to address. Governments, industry and academia tend to focus research funding on individual lifestyle risk factors such as smoking and alcohol consumption, years of education and levels of income, and reproductive characteristics such as when the first child was born, number of children and years of breastfeeding. In designing the questionnaire for their breast cancer epidemiological research, Brophy and Keith needed to include data not only on lifestyle and reproductive characteristics, but also to collect information about the jobs that people had undertaken, when they had done them and for how long. For each of the jobs there was an estimate of the amounts not only of the mammary carcinogens, but also of the endocrine disruptors that the worker would have been exposed to. This was a study quite different from the traditional, and the results implicated several industries.

The third of Dr Phil Brown’s axes concerned where controls should be focused. Industry tends to want as few controls as possible, such as government becoming involved regarding releases into the environment, or advice to consumers to reduce exposures to the chemicals in food, air and water and in consumer products. Occupational and environmental scientists / activists want controls on the manufacture and use of the chemicals. The results of Brophy and Keith’s paper indicate that some chemicals used in a variety of industries in southwestern Ontario are associated with elevated incidences of breast cancer and that exposures to these chemicals need to be tightly controlled.

What needs to be done? First, the Ministry of Labour needs to start improving working conditions in Ontario’s workplaces, to reduce exposures to chemicals and ensure that another generation of women workers is not injured. Second, as a result of neoliberal policies and the fear of jobs moving overseas, the union movements have been decimated in the past thirty years and have aligned with management to protect jobs. But they must also embrace their other roles and responsibilities that include protecting their membership, particularly women, from exposures to injurious chemicals. Third, since there is a strong association between certain occupations and breast cancer, this disease should be recognized as compensable under the provincial workers compensation schemes. Finally, funding organizations, such as the Canadian Cancer Society, the Canadian Breast Cancer Foundation, the Canadian Partnership Against Cancer, and similar organizations which annually receive millions of dollars, need to reorient their priorities from a focus on finding the cure and shift a significant amount of resources towards primary preventive measures including environmental and occupational epidemiology. This reorientation must include nominating knowledgeable lay people to their research review boards.

Michael Gilbertson is a Scientific Advisor, to Getting to Know Cancer


  1. Brophy JT, Keith MM, Watterson A, Park R, Gilbertson M, Maticka-Tyndale E, Beck M, Abu-Zahra H, Schneider K, Reinhartz A, Dematteo R, Luginaah I. 2012 Breast cancer risk in relation to occupations with exposure to carcinogens and endocrine disruptors: a Canadian case-control study. Environ Health. 11:87. doi: 10.1186/1476-069X-11-87.
  2. Proctor R. 1995. Cancer Wars: How Politics Shapes What We Know and Don’t Know About Cancer. New York: Basic Books.
  3. Bridbord K, Decoufle P, Fraumeni JF Jr, Hoel DG, Hoover RN, Rall DP, Saffiotti U, Schneiderman MA, Upton AC. Estimates of the fraction of cancer in the United States related to occupational factors. Testimony presented to Occupational Safety and Health Administration hearings, 15 September, 1978.
  4. Epstein, SS. 1978. The Politics of Cancer, San Francisco: Sierra Club Books.
  5. Doll R, Peto R. 1981. The causes of cancer: quantitative estimates of avoidable risks of cancer in the United States today. J Natl Cancer Inst. 66(6):1191-308.
  6. Brown P, McCormick S, Mayer B, Zavestoski S, Morello-Frosch R, Altman RG, Senier L. 2006. “A Lab of Our Own” Environmental Causation of Breast Cancer and Challenges to the Dominant Epidemiological Paradigm. Science, Technology, & Human Values. 31(5):499-536.
  7. McCormick S, Brown P, Zavestoski S. 2003. The Personal Is Scientific, the Scientific Is Political: The Public Paradigm of the Environmental Breast Cancer Movement. Sociological Forum, 18(4):545-576.