According to a study commissioned by Susan G. Komen for the Cure and the Silent Spring Institute, 216 chemicals, many found in urban air and everyday consumer products, cause breast cancer in animal tests. The study, “Environmental Factors in Breast Cancer,” the most comprehensive review to date of scientific research on environmental factors that may increase breast cancer risk, was published in the online version of the American Cancer Society’s journal Cancer on May 14, 2007.

The state-of-the-science review collected and assessed existing scientific reports on potential links between specific environmental factors and breast cancer. The researchers synthesized national and international data sources and identified 216 chemicals that cause breast tumors in animals, including ten pesticides. They used the information to create a searchable online database featuring detailed information on the carcinogens. The database, accessible at www.komen.org/environment, is available free of charge. The database includes references to 900 studies, 460 of which are human breast cancer studies that were critically evaluated by the research team. The studies measure breast cancer risk related to body size, physical activity, environmental pollutants, and prospective studies of diet. For each study, bibliographic information, key methods and findings, and a critical assessment of the strength of the evidence is included. 10 pesticides are listed as possible causes of breast tumors.