In late May 2020, the U.S. Environmental Protection Agency (EPA) placed around 40 additional warning signs at and around the former Humboldt Smelter property. These smaller signs are mounted to the new fencing and on posts in a line across where the tailings flood plain. These are in addition to the larger signs we added in 2019 (see December update). They warn of chemical and physical hazards in these areas.

We placed these additional warning signs:

along the new fence EPA installed in 2019 at the (northeast of the smelter plateau);

along the road/trail leading down to the smelter’s mine tailings area (southwest from the main gate);

along the mine tailings area where it enters the flood plain in the Chaparral Gulch (southwest of the smelter plateau); and

in the “parking area” and along the east side of the dross areas, near the smelter stack.

In addition, EPA also performed work at the front gate of the smelter to limit access. At the front gate, we added barbed wire to the top and added gravel underneath.

EPA also inspected the “Posi-Shell” covering we place in 2019 to control dust at the smelter property (see December update), and we determined it is in good shape.

In June 2020, EPA issued a reuse assessment of the former Humboldt Smelter property. EPA does not choose or pay for future land uses. However, we need to know what future land use the community might want. That way, we can see how our site cleanup options for the former smelter property can be compatible with the community’s reuse ideas. The ideas in the assessment were gathered over the past two years from key stakeholders and participants in EPA’s May 2019 workshop. This assessment summarizes the community ideas, describe how redevelopment has occurred at other Superfund sites and seeks to assist the community in thinking about how various redevelopment options could be implemented.

Community ideas for reuse include: open space, bike trails, walking trails, disc golf, recreational fields, recreational vehicle (RV) and camping, park space, amphitheater or event space, nature preserve and other economic development opportunities (such as businesses, waste treatment and solar panels).

The U.S. Environmental Protection Agency (EPA) has published a new fact sheet to remind parents to talk to their children/teenagers about staying away from the dangerous smelter and mine properties. We will mail it to our mailing list (roughly 3,000 addresses). This effort is to reinforce our messages from an October 2019 press release and fact sheet, in addition to an article we wrote for the July 2020 Dewey-Humboldt Newsletter.

In June, we placed over 40 additional warning signs at or near the former smelter property. The signs supplemented 9 larger warning signs around the site that we installed earlier in 2019. We also added barbed wire to the front gate at the smelter to better-restrict access. In addition, we inspected the “Posi shell” covering we placed in 2019 to control dust at the former smelter property, and we determined it was in good shape.

Over the summer, we worked with the Town of Dewey-Humboldt to arrange for installing a large warning sign on the Town’s property near the 3rd Street overcrossing of the Chapparal Gulch. The installed sign is down the path a short distance from the street. The sign is to warn hikers that the trail eventually opens into a flood plain with toxic tailings.

In June, the owner of the former Iron King Mine upgraded and added fencing around the mine pile. Last week, we installed 20 new small hazard warning signs along the new fence on the Iron King Road side of the former property.

We continue to work on our feasibility study of options to clean up the contamination across the whole site. In June, we issued a reuse assessment of the former Humboldt Smelter property to summarize what we heard from the community about approaches to reuse the smelter plateau. The forthcoming feasibility study uses the information EPA collected in the remedial investigation. It will compare a variety of cleanup options to address the contamination across the site. Before completing the feasibility study early next year, we would like to provide an update to Town Council and the public. However, we may need to plan for a virtual update, given the COVID pandemic.

Warnings Signs Humboldt Smelter; 3rd Street Warning Sign; Iron King Mine Road Warning Signs; Superfund Site Contacts

The U.S. Environmental Protection Agency (EPA) has developed a seven-part recorded presentation series on the Iron King Mine/Humboldt Smelter Superfund site. We hope this information helps you visualize the site, understand EPA’s Superfund process, and learn about the cleanup options we are studying to address the contamination.

To view the presentations, click on the titles in our flyer: https://go.usa.gov/x6vNq

The presentations are:

A Look at the Site (with Photo Tour)

Defining the Problem: The Remedial Investigation

Options for Cleanup: The Feasibility Study

Interim Dust Control, Fencing, and Signs

Residential Investigation and Cleanup

Future Reuse of the Smelter Property

A Health Concern: Natural Arsenic in Private Drinking Water Wells

EPA has been invited to the July 13, 2021 Dewey-Humboldt Town Council Study Session at 6:30 p.m. We look forward to virtually participating to answer questions from Councilmembers and discuss our ongoing study of options to address the contamination (called a feasibility study).

Please contact EPA with any questions using the contacts on our site webpage: www.epa.gov/superfund/ironkingmine

Yolanda Sanchez | U.S. EPA, Region 9 | Community Involvement for Superfund | Desk: 415-972-3880

The U.S. Environmental Protection Agency (EPA) is finalizing the feasibility study report of options to address the contamination at the Iron King Mine/Humboldt Smelter Superfund site. In the feasibility study report, we compare the options by considering the effectiveness of each option, the time it takes to complete, costs, and how the options might affect the community, among other factors. Our recent recorded presentation “Options for Cleanup: The Feasibility Study” explains this comparison.

We understand people want more information about the site and EPA’s work. This fall, we worked with the Town of Dewey-Humboldt on a plan to use our Technical Assistance Services for Communities (TASC) contract. TASC services help communities better understand EPA actions and help EPA better understand community concerns. Through TASC, we will provide additional information on naturally occuring metals in groundwater in Dewey-Humboldt and summarize the various exposure studies that have already been done in the community.

Questions have been raised about a town owned property at on Main Street (parcel 402-10-026A), next to the former rail corridor leading into the former Humboldt Smelter property. During our remedial investigation, we took 16 samples from soil across the property. The levels of lead and arsenic in the soil varied among the 16 samples. All levels were below EPA’s action levels needed for cleanup. Our sampling results showed that levels of lead and arsenic in the soil were low across the property and regular use of the property should not pose a significant health threat. We have been in recent communication with the Town of Dewey-Humboldt about this past work.

This fall, EPA coordinated with the Arizona Department of Environmental Quality (ADEQ) to understand options to address safety issues at the former Humboldt smelter property. In September, EPA and ADEQ visited the property with our contractors to evaluate options. Since July, we sent regular email updates to Town of Dewey-Humboldt staff and Councilmembers, and we provided an update to the community in the October Dewey-Humboldt Newsletter. This winter, EPA will continue to coordinate with ADEQ on its work to takedown the smelter smokestack and attached brick structure and install additional fencing. For information on ADEQ’s work, please visit: https://azdeq.gov/dh-stack-project.

For more information about EPA’s work at the Iron King Mine/Humboldt Smelter site, please visit: www.epa.gov/superfund/ironkingmine

ADEQ has created a drone video of he Humboldt Smelter takedown operation! The video can be found on the Smelter Stack Project website azdeq.gov/dh-stack-project or on YouTube www.youtube.com/watch?v=X7MqWxcra1Q

The latest Community Update regarding the completion of the Humboldt Smelter Project can be found here. 

The Environmental Protection Agency has released a cleanup plan for a former mine and Superfund site in Dewey-Humboldt.

The project is designed to clean up millions of tons of mine and smelter waste and contaminated soils at the Iron King Mine.

The work would put a permanent cap over some pollutants and freeze it in place so it doesn’t contaminate local waterways.

Decades ago, the former Iron King Mine and Humboldt Smelter left behind 8 million tons of mine tailings and other waste containing arsenic and lead.

It washed into drainages and the Agua Fria River, contaminated soils and continues to pose a health threat to people and wildlife.

It was declared a Superfund site in 2008. The EPA has already conducted five cleanups at the mine that included residential soils.

Public comment on the plan will be accepted until May 13th. Comments can be made by mailing them (postmarked by May 13th) to: Jeff Dhont (Phone: 415-972-3020), Remedial Project Manager, EPA Region 9, Mail Code SFD-8-1, 75 Hawthorne Street, San Francisco, CA 94105.

Comments can also be emailed to Thompson.Georgia@epa.gov and Dhont.Jeff@epa.gov or left via voicemail at (800) 231-3075.