A massive pile of wood debris caught fire and burned from October 27 to October 31, 2001, in northern Pinal County, Arizona. The fire consumed wood debris from citrus trees that had been stored in an approximately 25-acre area in Pinal County near the Queen Creek area. The fire generated a large quantity of smoke. Persons reported smelling the smoke up to 40 miles away from the fire. Meteorological conditions during the fire intermittently created conditions that limited lift, especially at night, causing smoke to settle in residential neighborhoods in the Queen Creek area. The Arizona Department of Health Services issued public health advisories for the evenings of October 29 and 30. This report summarizes the events that occurred during the fire and analyzes the data collected by the Arizona Department of Health Services and the Arizona Department of Environmental Quality to determine the extent of the public health threat from the fire.

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.