Bibliography on why there is concern about environmental chemicals and breast cancer risk. Includes information on chemicals in the workplace, light at night, chemicals in the home, pesticides and breast cancer risk, animals studies linking chemical exposure to mammary tumors, hormone therapy and breast cancer risk, emerging evidence of risk from hormone disrupting chemicals (flame retardants, plasticizers and heavy metals), early life exposures to chemicals (dioxin, atrazine, DDT, bisphenol A) and breast cancer risk, and the role of gene-environment interactions.