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Superfund / NPL site · EPA Superfund SEMS through latest publishNPL Final

Eastern Michaud Flats Contamination

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

Hwy 30, 3 Mi W Of City, Pocatello, Idaho · ZIP 83201 · EPA ID IDD984666610

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's In This Site

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
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)Groundwater3
AntimonyHealth riskInhaled antimony trioxide is an IARC Group 2B possible carcinogen; respiratory and cardiovascular effects from long-term exposure. EPA MCL 6 µg/L. (IARC, EPA)Soil2
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)Soil2
BerylliumSoil2
CadmiumSoil2
FluorideHealth riskBeneficial at low doses (1 mg/L) for dental health; chronic exposure above 4 mg/L causes skeletal fluorosis. EPA MCL 4 mg/L. (EPA)Groundwater2
FluorideHealth riskBeneficial at low doses (1 mg/L) for dental health; chronic exposure above 4 mg/L causes skeletal fluorosis. EPA MCL 4 mg/L. (EPA)Soil2
ManganeseHealth riskExcess inhalation can cause manganism, a Parkinson-like neurological disorder. (ATSDR)Groundwater2
ManganeseHealth riskExcess inhalation can cause manganism, a Parkinson-like neurological disorder. (ATSDR)Soil2
MercuryHealth riskNeurotoxin. Methylmercury bioaccumulates up the food chain and damages the developing nervous system. (EPA, ATSDR)Soil2
NickelHealth riskNickel compounds are IARC Group 1 carcinogens; inhalation exposure raises lung and nasal cancer risk. (IARC)Soil2
SeleniumSoil2
SilverHealth riskChronic exposure can cause argyria — irreversible blue-grey skin discoloration. Generally low systemic toxicity. (ATSDR)Soil2
ThalliumSoil2
VanadiumHealth riskRespiratory irritant. Chronic high exposure causes 'green tongue' and bronchitis. (NIOSH)Groundwater2
VanadiumHealth riskRespiratory irritant. Chronic high exposure causes 'green tongue' and bronchitis. (NIOSH)Soil2
ZincHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR)Soil2
Alpha GrossGroundwater1
Alpha GrossSoil1
AntimonyHealth riskInhaled antimony trioxide is an IARC Group 2B possible carcinogen; respiratory and cardiovascular effects from long-term exposure. EPA MCL 6 µg/L. (IARC, EPA)Groundwater1
BerylliumGroundwater1
Beta GrossGroundwater1
Beta GrossSoil1
BoronGroundwater1
BoronSoil1
CadmiumGroundwater1
ChromiumHealth riskHexavalent chromium (Cr-VI) is an IARC Group 1 carcinogen via inhalation, causing lung cancer; trivalent chromium is far less toxic. (IARC, EPA)Groundwater1
ChromiumHealth riskHexavalent chromium (Cr-VI) is an IARC Group 1 carcinogen via inhalation, causing lung cancer; trivalent chromium is far less toxic. (IARC, EPA)Soil1
Lead-210Soil1
MercuryHealth riskNeurotoxin. Methylmercury bioaccumulates up the food chain and damages the developing nervous system. (EPA, ATSDR)Groundwater1

Showing the top 30 pairs by SEMS citation count. 16 additional (contaminant, pathway) pairs are recorded for this site.

Drinking-water linkage · SDWIS

No Groundwater PWSes Serving Communities Within 3 Miles

No SDWIS public water systems drawing groundwater (or mixed sources) serve a community whose centroid sits within 3 miles of this site. Empty results are not a guarantee of non-impact — distance is computed to served-place centroids, and SDWIS does not expose individual wellhead locations.

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

Around this site Population Characteristics

EQUITY INGEST PENDING FOR THIS GEOGRAPHY

Idaho state-level (no place or county match).

Demographic shares, national-percentile rankings (PM2.5, ozone, NO₂, diesel particulate, lead-paint risk, NPL/RMP/TSDF/NPDES proximity, drinking-water non-compliance), and EJ disparity scores will render here once the EJScreen-clone ingest completes for this geography. Why this section matters →

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.