Legacy Groundwater Pollution from Unregulated Discharges
With the US Magnesium facility currently idled, some have suggested that the barrier wall that was designed to protect Great Salt Lake from the extensive contamination of groundwater beneath US Magnesium's unlined waste ponds is no longer needed. We disagree with that suggestion in the strongest possible terms. When FRIENDS was selected in 2013 to receive a Technical Assistance Grant from EPA to oversee the Superfund process at US Magnesium, one of the first tasks for our TAG Advisor, Dr. Bill Johnson, was to sort through an avalanche of documents describing the extent of the problem. There are reasons why the site was placed on the Superfund list by EPA, and one of those reasons was the clear evidence in documents generated by EPA that 40 years of essentially unregulated discharges left a legacy of pollution in groundwater that was headed towards the Lake. That legacy still exists today and still poses a substantial threat to the Lake's ecosystem.
To remind stakeholders about the documented extent of the contamination that exists beneath both the Current Waste Pond (CWP) and the Old Waste Pond (OWP), we're posting the documents below which summarize an analysis of that contamination:
2016-2017 Annotated Bibliography
Notes from Final OWP-CWP HydroCSM Annotated Bibliography
2017 Hydrogeologic Report: Groundwater Discharge Permit Application – Part C
What does US Mag declaring bankruptcy mean for the Lake?
US Magnesium has been making headlines again, and not in a good way. The facility has been non-operational since 2022, and on September 10, 2025, the company filed for Chapter 11 bankruptcy protection in Delaware, primarily due to environmental and financial liabilities.
Since 2013, FRIENDS has overseen cleanup of the US Magnesium Superfund site through a Technical Assistance Grant from EPA. The purpose of the TAG is to inform members of the public of the threats posed by the Superfund site as well as what needs to be done to address those threats.
With that charge, we asked our Technical Assistant Grant advisor, Dr. Bill Johnson, to summarize the most immediate threats existing today, as well as his recommendations regarding the actions needed to understand the extent of those threats.
Read the summary report below:
What’s Next Analysis of the US Magnesium Superfund Site
By William P. Johnson, TAG Advisor to FRIENDS of Great Salt Lake
Published on 09-18-2025
Key Points:
- Though US Magnesium has not been operational since 2022, contaminants from the site still pose a significant threat to human and ecosystem health.
- Dr. Bill Johnson's risk assessments demonstrated that human carcinogenic risk and risks to birds, mammals, and benthic invertebrates drastically exceeded regulatory benchmarks.
- There is evidence that groundwater pathways have transported and continue to transport contaminants away from the site.
- The need to further understand the area’s hydrology and the extent of contamination is urgent, especially because the containment wall around the waste pond has not been completed.
- Recommended action steps:
- Review of existing documents to assess contamination in CERCLA portion as existed during operation.
- Resampling of well hydraulic heads and retrieval of samples for analysis of selected contaminants in wells to understand changes in groundwater flow and current contaminant concentrations.
- Installation of additional piezometers for sampling of hydraulic head and contaminants at five to ten sparsely monitored zones on perimeter of older Waste Pond and beyond.
- 3D modeling of contaminant transport conditioned to current hydraulic head and contaminant concentrations to simulate likely transport scenarios for contaminants outward from the site.
Proposed Assessment of Contaminant Transport and Remediation at the US Magnesium Superfund Site
Four steps are outlined above to determine the extent to which contaminants have moved, are moving, and could continue to move, outward from the US Magnesium site. The document below is a proposal and budget to accomplish those steps in the geohydrologic framework as currently understood from previous work. The total budget for this proposed work is $213,300. Read the full proposal below:
Proposed Assessment of Contaminant Transport and Remediation at the US Magnesium Superfund Site
By William P. Johnson, TAG Advisor to FRIENDS of Great Salt Lake
Additional Background about US Magnesium and our TAG Work
Click here to visit our full US Magnesium webpage.