Living Near a Superfund Site

Soil, Water, and Plant Toxicity From the Iron King Mine and Humboldt Smelter

The Iron King Mine and Humboldt Smelter

The Iron King Mine and Humboldt Smelter

Mining near Humboldt, Arizona began in the mid 1800’s.  The Iron King Mine operated from 1904 until 1969 and produced a huge pile of waste rock and tailings.  The Humboldt smelter was active from the late 1800’s until the early 1960’s.  Like the mine, it produced a large pile of tailings.

The EPA conducted testing near the two sites and determined that there was a health risk for people, animals, and plants.  Some cleanup took place in 2006, and the two sites were placed on the National Priority List in 2008 (

After the Super Fund Site designation, I asked to be included in the preliminary testing for toxic materials in soil and water.  The EPA representative told me that there was no need to do testing around my home.  My house is about 1 1/4 miles East-Northeast of the main tailings pile.  At the time, I supposed that the scientists involved considered my home to be a safe distance from the tailings.  According to the 1500+ page Remedial Investigation Report of 2010 (, no samples were taken more than about a mile from the Sites.

According to the Superfund website, surveyors collected more than 1,000 soil samples in the mine and smelter areas, residential yards, and the Humboldt Elementary School.  Even near the mine, sampling is not complete.

“The full extent of residential impacts has not been determined as many yards have not yet been sampled. Additional parcels near the Chaparral Gulch or downwind of the Iron King Mine or Humboldt Smelter AOIs may be impacted by air particulate migration or surface water transport.  Additional soil sampling of parcels in the vicinity of these areas will assist EPA in fully evaluating the impacts to residential and public areas (see Figure ES-7)” (p. x of the Executive Summary, EA Project No. 14342.34, Revision 01, March 2010:

In 2010, a graduate student at the University of Arizona began the Gardenroots project.  The student called for homeowners living near the Super Fund site to send samples of their soil, water, and garden vegetables for analysis.  Twenty-five homeowners volunteered.  I was one of them, and I got my results back a few months ago.  Last month, I received a summary of the results for all 25 homeowners.

The Results for My Home

The tests found unsafe levels of arsenic in my soil, water, and plants.  I submitted samples of plants most heavily used by wildlife:  Sunflowers, Hyssop flowers, pears, and Barnyard Grass.  My test report included a list of recommendations for safe gardening.  According to the list, I should:

  1.    Limit consumption of all the plants I submitted.
  2.    Avoid breathing dust from my garden
    1. Don’t garden on windy days
    2. Don’t eat or drink while in the garden
    3. Keep soils moist while gardening
    4. Use certain clothes while gardening and store the clothes outside.
    5. Consider wearing a mask
    6. Wash hands and exposed body surfaces after gardening
    7. Leave shoes outside
    8. Frequently mop floors and wipe down surfaces inside the house
    9. Change the vacuum bag often
  3.    Don’t drink my well water.

Gardening at my home is a lot like working around a nuclear reactor.  The list of recommendations didn’t include wearing a white plastic jump suit, but if I did, I could just pull off the jumpsuit and wouldn’t have to change clothes outdoors.

Bare soil occurs in many places around my house.  Arsenic and other toxic elements are poisoning all plants, people, and animals in contact with the soil.

What Were the Results for All 21 Homes In the Gardenroots Study?

The results for most of the homes of the 21 volunteers were the same as mine.  In fact, arsenic levels in half of the 21 yard and garden soils exceeded the standard for cleanup set by the AZ Dept. of Environmental Quality.


My house was not a safe distance from the tailings.  In fact, the Gardenroots project found hazardous arsenic levels well above the average for Yavapai County up to eight miles from the tailings pile.  Could it be that a century of blowing dust has spread arsenic, lead, and other toxic materials over a larger area than at first believed by the EPA scientists?

More Information Needed

The EPA website ( and the documentation for the Iron King Mine and Humboldt Smelter ( contain thousands of pages of useful information.  I have not read much of it, but I think the sampling the EPA conducted was too limited to show the distribution of toxic materials from the two sites.  The 21 sites included in the Gardenroots project are not an adequate sample for generalizing about the region.  They suggest that toxic elements from the sites are widespread, but more samples are needed.

2 thoughts on “Living Near a Superfund Site

  1. Hello! My Fiance and I are considering buying a home on Rancho in Dewey Humboldt…Very much enjoyed reading your article! Very informative! Can You tell me if the tailings have been covered now where they no longer blow? And, even if they have been covered where they can no longer blow into the wind is the soil already so contaminated that it would be years before it won’t be? Sorry for my ignorance on this. I have tried and tried to find more information, and Your article actually is the most informative! My email address is I would love to hear from You! Thanks so much! Kathleen Johnson


  2. Hi Kathleen,

    I think the tailings have been covered.

    Arsenic occurs here and there naturally in Arizona. Over the past century the Humboldt Mine and Smelter site might have added to natural deposits on your home site. I think the best idea is to accept that any preliminary home inspection should include yard soil and water (if you have a well) testing for pollutants. It’s the only way to know for sure what is present on any given site.

    The EPA is sending someone to the D-H Town Council meeting to present an update and answer questions pretty soon. I am not sure of the date. Call Dewey-Humboldt Town Hall for the date.





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