The United States Environmental Protection Agency asked the Arizona Department of Health Services, Office of Environmental Health, to provide an evaluation of the health hazards that may result from exposure to soil and soil gas contaminants present on the West-Cap site, located just north of the Tucson International Airport. Improper waste disposal practices from previous industrial activities at the site have resulted in contamination of on-site soil and soil gas. The objective of this health assessment is to assess the potential adverse health impact to on-site workers from exposure to the on-site contaminated soil and soil gas. Community exposures are not presented in this public health assessment.

The Arizona Department of Health Services Cancer Registry has identified 7 cases of childhood leukemia in the Sierra Vista, Arizona area since 1995. Five of the childhood leukemia cases were identified as a class of lymphoid leukemia and 2 of the cases were a class of myeloid leukemia. Based on random variation, a total of 6 or fewer cases of leukemia would have been expected over those seven years. An analysis of the data suggests that the number of cases is statistically elevated for the time period 1995 to 2001. The objective of this report is to determine whether there are any documented environmental exposures from drinking water, ambient air or waste sites that may have placed residents of the Sierra Vista, Arizona area at greater risk of developing childhood leukemia.

In May 2003, a Scottsdale, Arizona, resident asked the Agency for Toxic Substances and Disease Registry in Atlanta to investigate possible sewer gas exposures in a Scottsdale residential neighborhood. In June 2003, the Agency asked the Arizona Department of Health Services, to conduct an investigation to determine if sewer gas exposures were occurring. Because ambient and indoor air hydrogen sulfide data for the neighborhood were not available, the Arizona Department of Health Services and the resident collaborated in conducting an air monitoring investigation in the neighborhood from June 26, 2003, through July 15, 2003.

The Arizona Department of Health Services reviewed existing data and performed a health consultation to evaluate the potentially adverse health effects due to VOCs created by air emissions from the Miller Road Treatment Facility. Prior to the existence of our current environmental regulations, local industries improperly disposed of organic solvents directly onto the ground or into dry wells. This subsequently contaminated all three levels of the aquifer.