|Iron King Mine - Humboldt Smelter||Dewey-Humboldt, Arizona|
The site consists of toxic waste sources at the Iron King Mine and the Humboldt Smelter facilities and contaminated ground water and soil attributable to the mine and smelter sources. Both the mine and smelter are located in industrial, commercial, and/or residential areas of Dewey-Humboldt, Arizona. The Iron King Mine is located near the intersection of Highway 69 and Iron King Road. The Humboldt Smelter is located near the intersection of 3rd Street and Main Street.
The Iron King Mine was an active mine, off and on, from 1906 (when the mine produced fluxing ore for the Humboldt Smelter) until 1969. Ore from Iron King Mine was processed at the Humboldt Smelter, which operated from the late 1800s until the early 1960s. In addition to mining, activities at the mine facility included waste reduction and converting mine tailings to fertilizer. The waste reduction facility sorted wastes, sent recyclable materials off-site, and disposed of construction debris in an on-site collapsed mine shaft.
The Iron King Mine facility covers 153 acres, the majority of which is covered by waste rock piles and tailings (the tailings pile measures approximately 62 acres). There are five retention ponds, at least five mine shafts, a large collapsed mine shaft, and numerous areas of stained soil. The smelter facility occupies approximately 189 acres and has approximately 763,000 square feet of tailings, 1,041,200 square feet of grey smelter ash, and 456,000 square feet of slag. On-site ponds, pits, and lagoons were reportedly used for the leaching of minerals from mined ore. Arsenic and other metals have contaminated soil, sediments, surface water and ground water on-site at levels significantly above background. Arsenic and lead have been found significantly above health based standards in the soil of several residential yards. Results for several private drinking water wells and a municipal well show arsenic above EPA's Safe Drinking Water Act maximum contaminant levels (MCLs).
Potential Impacts on Surrounding Community/Environment:
A significant residential portion of the Town of Dewey-Humboldt sits between the mine and the smelter. At this time, the full extent of soil contamination and possible ground water contamination has not been assessed.
Response Activities (to date):
In 2005, a removal of contaminated soil from four residential properties was conducted by a contractor on behalf of the Ironite Products Company, under EPA oversight.
Need for NPL Listing:
The State of Arizona referred the site to EPA because of lack of alternative funding for cleanup at this time. EPA received a letter of support for placing this site on the NPL from the state. The Mayor and City Council of Dewey-Humboldt also voted in support of placement on the NPL.
[The description of the site (release) is based on information available at the time the site was evaluated with the HRS. The description may change as additional information is gathered on the sources and extent of contamination. See 56 FR 5600, February 11, 1991, or subsequent FR notices.]
For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet at ATSDR - ToxFAQs (http://www.atsdr.cdc.gov/toxfaqs/index.asp) or by telephone at 1-888-42-ATSDR or 1-888-422-8737.