About Superfund sites: According to a nationwide survey conducted by the Agency for Toxic Substance and Disease Registry, a branch of the U.S. Public Health Service, "uncontrolled hazardous waste sites are a major environmental threat to public health." The survey cites epidemiological studies which found that people living close to hazardous waste sites have increased incidence of birth defects, liver disease, and disorders of the immune and nervous systems. There is also a link between toxic waste sites and breast cancer. For example, a nationwide survey of waste dumps and cancer incidence conducted from 1970 through 1979 found that breast cancer is increased in 339 U.S. counties that have hazardous waste sites and ground water contamination as compared with counties that do not have such sites, along with several other cancers: "Significant associations (p < .002) [i.e., 99.8% certain that variation in deaths is not random] between excess deaths and all HWS [hazardous waste site] counties were shown for cancers of the lung, bladder, esophagus, stomach, large intestine, and rectum for white males; and for cancers of the lung, breast, bladder, stomach, large intestine, and rectum for females" (Jack Griffith and Wilson B. Riggan, "Cancer Mortality in U.S. Counties with Hazardous Waste Sites and Ground Water Pollution," Archives of Environmental Health, Vol. 44, No. 2. March/April 1989, pp. 69-74).