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Ongoing Investigation at the Site


Tianna Kilgore
EGLE Environmental Engineer

Todd Zynda
EGLE Hazardous Waste Inspector

Jon Lamb
EGLE Air Quality Division, Senior Environmental Quality Analyst

Vault 703 Fire

On December 28, 2022, the Michigan Department of Environment, Great Lakes, and Energy (EGLE), Materials Management Division (MMD) was notified of a fire that started in the Chemical Fixation (Chem-Fix) Building during treatment of a hazardous waste batch in Vault 703, one of six in-ground tanks licensed for hazardous and solid waste treatment activities. It is suspected that the fire was caused by a flammable waste stream that was accepted by USEDS from an out of state generator.

MMD and AQD staff conducted an incident inspection at the site on December 29, 2023, following the fire to ensure the situation was under control. MMD staff conducted a Focused Compliance Inspection (FCI) on January 5, 2023. As part of the emergency procedures, Vault 703 was taken out of service until a registered Professional Engineer could inspect and certify that the fire did not compromise the integrity of the vault.

Issues with the Chem-Fix Building Vaults and Ongoing Investigation

On April 19, 2023, MMD staff conducted an inspection of the US Ecology Detroit South facility. During this inspection, the Chem-Fix Building Vaults 701 through 706 were inspected. It was revealed that liquid was present in the leak detection ports of the vaults, and that US Ecology has been regularly pumping the wells since at least 2018. Liquid present in the leak detection ports is a concern because the high liquid accumulation suggests that there could be a connection to the subsurface and therefore a release could have occurred.

A Violation Notice (VN) was issued for this inspection on May 31, 2023, which included failure to notify the MMD of the liquid accumulation, and for inaccurately documenting inspection findings on inspection forms. In the VN, MMD advised that US Ecology cease operation of the vaults immediately to comply with federal regulations. The Chem-Fix Building and treatment vaults were shutdown on June 9, 2023.

On June 7, 2023, the MMD conditionally approved the Hydrogeological Investigation Work Plan that US Ecology submitted, as requested by MMD in the VN. The work detailed in the Work Plan was just the first step of the investigation, and focused on determining the geological conditions on-site, especially in the immediate vicinity of the vaults, and collecting an initial round of groundwater samples. US Ecology submitted a Hydrogeological Evaluation Report, dated August 4, 2023, detailing the results of the initial round of sampling GZA GeoEnvironmental, Inc. (GZA) performed on behalf of US Ecology, and the information obtained from those samples.

At this time, work is still ongoing and additional sampling will be needed before determining the source of the water present in the leak detection ports and if a release has occurred.

Available using the links below are the initial Hydrogeological Evaluation Report and all of MMD’s sampling results pertaining to the investigation.

Enforcement Actions

All of the Violation Notices (VNs) that were mentioned in the sections above, and others, have been cited in the Enforcement Notice that MMD issued to US Ecology on August 14, 2023. Available using the links below are the Enforcement Notice, which includes all of the cited VNs as attachments and MMD’s response to US Ecology’s review of the VN, issued May 31, 2023 and the most recent VN that was issued on September 12, 2023.