Governor Janet Napolitano recently formed a task force of representatives from four state agencies - the departments of Environmental Quality, Water Resources, Health Services and Agriculture - to investigate the occurrence levels of perchlorate in Arizona water sources; the risks, if any, it poses to public health; whether Arizona should develop a water quality standard for perchlorate and to make recommendations for future action, if necessary.

Perchlorate is a man-made compound used in the production of solid rocket fuel, fireworks, air bags and munitions. It is odorless, colorless and tasteless and breaks down very slowly in the environment. Perchlorate has been used as a propellant for rockets and missiles since World War II, so improper or outdated disposal practices in the past may have allowed perchlorate to contaminate both ground and surface water supplies.

Two manufacturing facilities near Henderson, Nevada have utilized perchlorate since the 1940s. Large amounts of process wastewater containing perchlorate have been discharged into unlined evaporation ponds. Over time, the aquifer beneath the facility and the ponds became contaminated with high levels of ammonium perchlorate. The groundwater from that aquifer seeps into the Las Vegas Wash which drains into Lake Mead and ultimately into the Colorado River as it flows through the Hoover Dam. Detectable concentrations of perchlorate have been found along the river from Lake Mead to Yuma. Thus the four-agency task force is conducting reconnaissance sampling across the state to determine levels of perchlorate in ground and surface waters today.

ADEQ has created this Web page as a source of information about perchlorate. Questions regarding perchlorate should be directed to John Calkins at (602) 771-4617 or, toll free, at (800) 234-5677.

Frequently Asked Questions

See also:
  12/10/04: Report - Perchlorate in Arizona; Occurrence Study of 2004 (revised)
  Proposed Sampling Locations
  Sampling and Analysis Plan

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