EPA Superfund Site

MONTICELLO MILL TAILINGS (USDOE)

UT | EPA ID UT3890090035

About this site’s exposure pathways: As of October 2023, the Monticello Mill Tailings Superfund site is considered Insufficient Data to make a Human Exposure evaluation (HEID) because of a newly identified exposure pathway and⁄or contaminant(s) that may be possible since segments of Montezuma Creek are designated for domestic drinking water, and uranium concentrations has been observed in some surface water samples. The site was previously categorized as Current Human Exposure Controlled and Protective Remedy in Place (HEPR) and in the 2022 Five-Year Review (FYR) Report it was identified that additional information is needed to evaluate whether the remedy is functioning as intended and protective of human health and the environment.
EPA uses this Human Exposure status when there is a lack of evidence to suggest that actual or reasonably anticipated human exposures are occurring, and that those exposures are above acceptable risk-based levels. The planned activities to collect sufficient information to evaluate this new exposure pathway and⁄or contaminants(s) are the following: 1) Completion of a feasibility study to evaluate remedial alternatives of the remedy for Operable Unit III to achieving the water quality restoration goals, 2) Evaluation of risk to human health and aquatic organisms using current state water quality standards, and 3) Evaluation to determine if institutional controls are required to prevent human consumption of surface water. EPA and US Department of Energy Legacy Management (DOE LM) currently anticipates that there will be sufficient data to make a Human Exposure evaluation by October 31, 2024, because the issues and recommendations identified in the FYR will have been completed.