Pollution Analyst
How it works→
Superfund / NPL site · EPA Superfund SEMS through latest publishNPL FinalFEDERAL FACILITY

Monticello Mill Tailings (Usdoe) Superfund

This site is currently on the EPA Superfund National Priorities List and remains under federal cleanup oversight. Most-cited contaminant of concern: Uranium.

T335,R23E,S31-T335,R24E,S36, Monticello, Utah · ZIP 84535 · EPA ID UT3890090035

See San Juan ContaminantsEquity contextHow we read Superfund data
CLEANUP TIMELINE

Listing-date and cleanup-phase enrichment from EPA's per-site SEMS profile is queued for a follow-up ingest pass. Until then, this section will populate from EPA's published timeline data.

Anomaly engine

Notable Signals

No notable signals at this Superfund site for the current ingest. Cleanup-phase and SEMS-action flags are deferred to a follow-up engineering pass.

Contaminants of concern · per EPA SEMS

What Contaminants Are In Monticello Mill Tailings (Usdoe)

Each row pairs a contaminant with the medium it was found in (the exposure pathway). Hover any named contaminant for an agency-cited health-risk summary. Cited count = number of SEMS decision records (RODs and related) that name the pair.

ContaminantPathwayCited
UraniumHealth riskIARC Group 1 carcinogen; chemical kidney toxicity exceeds the radiological risk at most environmental levels. EPA MCL 30 µg/L total uranium. (IARC, EPA)Surface Water2
Alpha GrossGroundwater1
Alpha GrossSurface Water1
ArsenicHealth riskIARC Group 1 carcinogen via inhalation and ingestion. EPA MCL 10 µg/L; chronic exposure causes skin, lung, bladder cancer and cardiovascular disease. (IARC, EPA, ATSDR)Groundwater1
ArsenicHealth riskIARC Group 1 carcinogen via inhalation and ingestion. EPA MCL 10 µg/L; chronic exposure causes skin, lung, bladder cancer and cardiovascular disease. (IARC, EPA, ATSDR)Solid Waste1
ArsenicHealth riskIARC Group 1 carcinogen via inhalation and ingestion. EPA MCL 10 µg/L; chronic exposure causes skin, lung, bladder cancer and cardiovascular disease. (IARC, EPA, ATSDR)Surface Water1
Beta GrossGroundwater1
Beta GrossSurface Water1
CopperHealth riskInhaled copper fumes cause metal-fume fever; chronic ingestion above EPA's 1.3 mg/L action level damages the liver. (EPA)Solid Waste1
Gamma Radioactivity EmittersSolid Waste1
LeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR)Solid Waste1
ManganeseHealth riskExcess inhalation can cause manganism, a Parkinson-like neurological disorder. (ATSDR)Groundwater1
ManganeseHealth riskExcess inhalation can cause manganism, a Parkinson-like neurological disorder. (ATSDR)Surface Water1
MolybdenumGroundwater1
MolybdenumSurface Water1
NitrateHealth riskDrinking-water nitrate causes methemoglobinemia ('blue-baby syndrome') in infants; EPA MCL is 10 mg/L as N. (EPA)Groundwater1
NitrateHealth riskDrinking-water nitrate causes methemoglobinemia ('blue-baby syndrome') in infants; EPA MCL is 10 mg/L as N. (EPA)Surface Water1
Radium-226Health riskIARC Group 1 carcinogen (Ra-226 and Ra-228); bone-seeking radionuclide; alpha emitter. EPA combined MCL 5 pCi/L for radium-226+228 in drinking water. (IARC, EPA)Soil1
Radium-226Health riskIARC Group 1 carcinogen (Ra-226 and Ra-228); bone-seeking radionuclide; alpha emitter. EPA combined MCL 5 pCi/L for radium-226+228 in drinking water. (IARC, EPA)Solid Waste1
RadonSolid Waste1
SeleniumGroundwater1
SeleniumSolid Waste1
SeleniumSurface Water1
SodiumGroundwater1
SodiumSurface Water1
SulfateGroundwater1
SulfateSurface Water1
UraniumHealth riskIARC Group 1 carcinogen; chemical kidney toxicity exceeds the radiological risk at most environmental levels. EPA MCL 30 µg/L total uranium. (IARC, EPA)Groundwater1
UraniumHealth riskIARC Group 1 carcinogen; chemical kidney toxicity exceeds the radiological risk at most environmental levels. EPA MCL 30 µg/L total uranium. (IARC, EPA)Solid Waste1
Uranium-234Health riskIARC Group 1 carcinogen; chemical kidney toxicity exceeds the radiological risk at most environmental levels. EPA MCL 30 µg/L total uranium. (IARC, EPA)Groundwater1

Showing the top 30 pairs by SEMS citation count. 9 additional (contaminant, pathway) pairs are recorded for this site.

Drinking-water linkage · SDWIS

Groundwater Systems Serving Communities Within 3 Miles

The 3 systems below draw on groundwater (or mixed sources) and serve communities whose centroid sits within 3 miles of this site. Distance is to the served-city centroid — SDWIS does not expose individual wellhead locations, so this is a proximity screen, not a wellhead-impact assessment.

Water systemServesDistancePopulation servedSourceStatus
Eastland Special Service District MunicipalMonticello0.5 mi90GROUNDWATERUNRESOLVED
Pack Creek Water Company PrivateMonticello0.5 mi75GROUNDWATERUNRESOLVED
Rockland Ranch PrivateMonticello0.5 mi175GROUNDWATERUNRESOLVED

Methodology: served-city centroid (TIGER 2020) is used as the PWS coordinate. Source-water classification from SDWIS primary_source_code; only groundwater and mixed-source systems are queried. Click any system above for its full SDWIS profile.

Equity context · ACS 2018-2022 block-group demographics

Who Lives Near This Site

San Juan County, Utah (no Census block groups within 1 mile and no host city — falling back to containing county): a population of 14,524. Why we surface this →

POPULATION SHARE
20.7%

Low-income

POPULATION SHARE
56.2%

People of color

POPULATION SHARE
9.2%

Under age 5

POPULATION SHARE
15.5%

Over age 64

Source: Census ACS 2018-2022 (5-year) + USEPA-clone EJ blockgroup stats (raw indicators + EJ disparity mirror). NPL site proximity contributes to the national EJ pattern; indicator-level percentile and disparity scores are surfaced on the county page and the state page.

Source. EPA Superfund Enterprise Management System (SEMS) · retrieved 2026-05-07. SEMS is a federal public-domain dataset under 17 USC §105.

What this is not. We report EPA's published Superfund record — site listing, status, and contaminants of concern as named in EPA's decision documents. We do not perform site visits, independent air or water sampling, or current-state health-risk assessment. NPL listing reflects EPA's Hazard Ranking Score at a point in time; it does not by itself describe present-day exposure.