The Arizona Department of Health Services was asked by the Arizona Department of Environmental Quality to evaluate the potential health effects from inhalation of toxic vapors as a result of an unplanned, concentrated nitric acid release. According to Hudson Farms, at approximately 1 pm on July 1st, concentrated nitric acid began escaping from a small leak in a 33,000 gallon storage tank. By 4:30 pm, the first responding fire department units observed an orange colored plume that was moving with the wind direction. The large plume continued to dissipate throughout the area until about 8:30 pm that night. Small amounts of nitric acid that was generally restricted to the Hudson property continued to leak until approximately 8 am the morning of July 2nd when pumping of acid waste waters into emergency storage tanks was completed. It is estimated by ADEQ that a total of 4,0 00-4,500 gallons of concentrated nitric acid was released from the storage tank. Approximately 600 people from the town of Laveen and the Gila River Indian Community were immediately evacuated. Residents were allowed re -entry to their homes the following day, July 2nd at approximately 10 am.

Local residents expressed their concerns regarding the tailings from the Iron King Mine and Humboldt Smelter at Dewey-Humboldt, AZ. The purpose of this health consultation is to evaluate the available water and soil sampling results to determine if the detected metal levels pose adverse health effects when residents come into contact with the water or soil. In 2008, EPA initiated the field investigation portion of the Remedial Investigation and Feasibility Study for the Site. The primary objectives of the RI/FS are to determine the nature and extent of contamination and to gather sufficient information so that EPA can select a long-term remedy that eliminates, reduces, or controls risks to human health. The investigation included the collection of airborne particulates, groundwater, surface water, surface soil, subsurface soil, and sediment data across the entire Site. Data from the RI/FS was not available at the time the health consultation was prepared and thus it was not incorporated into this health consultation.