The objective of this assessment is to evaluate whether a public health hazard exists as a result of environmental exposures in Hayden and Winkelman, Arizona, located near a smelter operated by ASARCO, Inc. Some of the residents of these towns have expressed concerns that metals from smelter emissions over the years have been causing health problems. This report uses environmental data collected from water, soil, and air in the Hayden and Winkelman area to estimate environmental exposures. The study also evaluates available health outcome data from previous epidemiological and biological-monitoring studies conducted in the area. The report concludes that exposure to sulfur dioxide occasionally poses a short-term public health hazard to sensitive asthmatics. These episodes of higher levels of sulfur dioxide occur infrequently. They do not appear to pose a health hazard to persons without sensitive airways or asthma. Other environmental exposures do not appear to pose a public health hazard.

The Miller Road Treatment Facility was built by the North Indian Bend Wash Participating Companies to treat groundwater in order to reduce the levels of volatile organic compounds that have contaminated the aquifers. The facility was brought on-line in March 1997, and ownership was transferred to AAWC in December 1997. The facility processes the groundwater to remove the VOCs. Between January 15–17, 2008 trichloroethylene (TCE) was detected in the Paradise Valley Water System. Arizona American Water Company, who own and operate the Paradise Valley system, contacted the Arizona Department of Health Services and requested assistance in determining possible health risks from exposures related to this incidence. In response, the Arizona Department of Health Services reviewed existing data and performed a health consultation to evaluate the possibility of adverse health effects associated with this event.