In the early 1990s, breast cancer advocates petitioned the United States Congress to investigate the high rates of breast cancer on Long Island in the state of New York. The resulting law led to the Long Island Breast Cancer Study Project (LIBCSP)--more than ten research projects designed to study the possible causes of this increased incidence of cancer. This project reported that there was no evidence that environmental exposures were responsible. Controversial from its start, the LIBCSP has had an important role in efforts to understand the reasons for the high rates of breast cancer in some regions of the United States.