Breast Cancer and the Environment

By Breast Cancer Action |

Breast cancer is a complex disease that occurs in an environmentally complex world. A woman’s lifetime risk for developing breast cancer increases as she ages, and the established risk factors for breast cancer account for only a fraction of the cases. Indeed, incidence of breast cancer is rising faster than hereditary or lifestyle factors can explain.

There is growing evidence of health harms, including breast cancer, from exposures to a range of chemicals and toxins. In fact, the President’s Cancer Panel reported in 2010 that “the true burden of environmentally induced cancer has been grossly underestimated [and]…the American people—even before they are born—are bombarded continually with myriad combinations of these dangerous exposures.”

What We Know

50-70 percent of women with breast cancer have no known risk factors. Known risk factors include family history, early onset of menstruation, late menopause, late or no childbirth, alcohol consumption and ionizing radiation from x-rays. (For more information, see Risk Factors for Breast Cancer.)

Repeated exposure to toxic environments is related to an increased risk of breast cancer. At-risk groups include people who work frequently with toxic chemicals and ionizing radiation, such as farmers, nail technicians, chemists, and radiology technicians.

Timing of exposure is significant. Exposure to harmful environmental toxins during certain periods of rapid breast development is more harmful than the same exposure once the breast tissue is fully developed. These “windows of susceptibility or vulnerability” include in utero, puberty, pregnancy and menopause.

Currently, the lifetime exposure to environmental contaminants is extremely understudied.

Although there are numerous studies that point to associations between exposure to environmental toxins and high rates of breast cancer, exposure to ionizing radiation is the only confirmed exposure that raises a woman’s risk of developing breast cancer. Suspected carcinogens for breast cancer include polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB), formaldehyde and endocrine disrupting chemicals such as DDT, Bisphenol A (BPA), phthalates and parabens.

Low dose exposure to endocrine disrupting chemicals is important and can have serious effects on human health. In order to understand the effects that chemicals have on the body, they should be tested in ultra-low doses that imitate real human experiences.

The effects of exposure to chemicals can persist well beyond the time they were banned. For example, the pesticide DDT banned in 1972 was found in 65 percent of Cape Cod and 85 percent of California dust samples in 1999-2001.

Chemical Exposures Come from Many Sources

We are exposed to multiple chemicals on a daily basis from many different sources that potentially increase our risk of developing breast cancer. We cannot put the burden on consumers to buy “safer” products. Below are examples of some of the ways we are routinely exposed.

Through the food we eat – pesticides on produce, Recombinant bovine growth hormone (rBGH) in dairy products, BPA in cans and hard plastics and Perfluorooctanoic acid (PFOA) in nonstick coatings on cookware.

Through the products we use – flame retardants in furniture, phthalates and parabens in personal care products, nonyphenols in cleaning products, detergents, shampoos and paints.

Through the environment in which we live – chemicals of concern used in the fracking process for natural gas and oil and fossil-fuel exhaust from automobiles and power plants.

Everyday Chemicals are Grossly Under-Regulated

The Toxic Substances Control Act (TSCA) of 1976 did not require any safety testing for all chemicals that were in existence prior to 1976 to remain on the market. In the 36 years since TSCA was enacted, less than two percent of the more than 80,000 chemicals used and produced in the U.S. have been tested for safety.

Production and use of synthetic chemicals is on the rise. Following the World War II industrial boom, the growing incidence of breast cancer has paralleled the increased production of synthetic chemicals.1 Of an estimated 80,000 synthetic chemicals in commercial use today, more than 90 percent have never been tested for their effects on human health. Meanwhile, production of these chemicals is rising at least 3.3 percent per year.2

The use of terms such as “natural”, “non-toxic”, and “safe” in product labeling is not adequately regulated in the U.S. The U.S. Federal Trade Commission has created some guidelines for environmental marketing, but they are rarely enforced.3

Breast Cancer Action’s Perspective

Structural change to our regulatory system is necessary. While BCAction supports individuals making choices about products they buy, we know this isn’t enough to protect everyone from the effects of multiple chemicals in our daily lives. Focusing on comprehensive change to reform chemical policy has the potential to protect everyone.

Disadvantaged populations, especially communities of color, are more likely to be employed in occupations with higher levels of toxic chemical exposure such as manufacturing, agriculture, and certain service sector occupations. They are also more likely to live in more highly contaminated communities. Studies have shown that these unequal exposures result in racial and ethnic differences in chemical body burdens of certain chemicals such as flame retardants, BPA and phthalates.

Support the Precautionary Principle. Currently, in the U.S., the prevailing approach to chemical regulation is reactionary. Instead, we should take a precautionary approach and act now with the evidence we have to reduce risk of harm to human health. We need to shift the burden of proof to companies making chemicals and products and insist that are proven safe before arriving in the marketplace.

Research into environmental links to diseases should be a priority, and it must be funded independently, not by the very companies producing chemicals. In order to stop cancer where it starts, we need to spend as much time and money researching causes, as we have spent on developing treatments.

Broad Chemical Reform Is Necessary

Strong legislation reforming our chemical regulations will reduce our exposure to toxic chemicals that lead to many health harms, including breast cancer. Strong chemical regulation must address:

  • Burden of Proof
  • Precautionary Principle
  • Expedited Action on the Worst Chemicals
  • Protection for Heavily Impacted Communities
  • Allowance for Stronger Laws
  • Establish Deadlines and Timetables

What You Can Do

Support strong chemical reform. Urge your state senator to support stronger regulation of toxins linked to breast cancer.

Get informed! Read “Living Downstream” by Sandra Steingraber, “Silent Spring” by Rachel Carson, and “Exposed” by Mark Shapiro.

Stay current by subscribing to BCAction’s newsletter, “The Source“.

Check out the following environmental health and justice organizations:


    1. Theo Colburn, Dianne Dumanoski, and John Peterson Myers, “Our Stolen Future: Are We Threatening Our Fertility, Intelligence, and Survival? A Scientific Detective Story”, (New York: Dutton, 1996), 137. [Return to text]
    2. Steingraber, S., Living Downstream: A Scientist’s Personal Investigation of Cancer and the Environment, p.281, New York: Vintage Books, 1998. [Return to text]
    3. Steingraber, S., Living Downstream: A Scientist’s Personal Investigation of Cancer and the Environment, p.281, New York: Vintage Books, 1998. [Return to text]

This article is based on the fact sheet “What You Should Know About Breast Cancer & the Environment” by Breast Cancer Action, a national, feminist grassroots education and advocacy organization working to end the breast cancer epidemic.