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

Libby Ground Water Contamination

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

252 Port Blvd., Libby, Montana · ZIP 59923 · EPA ID MTD980502736

See Lincoln 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
Benzo[A]AnthraceneHealth riskPAH; IARC Group 2B possible carcinogen; common combustion byproduct and creosote constituent. (IARC)Groundwater4
ChryseneGroundwater4
FluorantheneGroundwater4
NaphthaleneHealth riskIARC Group 2B possible carcinogen; causes hemolytic anemia, especially in infants. (IARC)Groundwater4
PentachlorophenolHealth riskIARC Group 1 carcinogen; wood preservative; persistent in soil and groundwater. (IARC, EPA)Groundwater4
PyreneGroundwater4
9H-FluoreneGroundwater3
AnthraceneGroundwater3
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
BenzeneHealth riskIARC Group 1 carcinogen. Long-term inhalation causes leukemia and bone-marrow disorders. (IARC, EPA)Groundwater3
1,2-DihydroacenaphthyleneGroundwater2
Benzo(B)FluorantheneGroundwater2
Benzo(K)FluorantheneGroundwater2
Benzo[A]PyreneHealth riskPAH; IARC Group 1 carcinogen; the prototypical PAH used to benchmark PAH-mixture cancer risk. EPA MCL 0.2 µg/L. (IARC, EPA)Groundwater2
Carcinogenic Polycyclic Aromatic Hydrocarbons (Cpah)Health riskPAH class includes IARC Group 1 carcinogens (e.g., benzo[a]pyrene); long-term exposure raises cancer risk. (IARC, EPA)Soil2
CopperHealth riskInhaled copper fumes cause metal-fume fever; chronic ingestion above EPA's 1.3 mg/L action level damages the liver. (EPA)Groundwater2
Dibenzo(A,H)AnthraceneGroundwater2
EthylbenzeneHealth riskIARC Group 2B possible carcinogen; eye and respiratory irritant. (IARC)Groundwater2
Indeno(1,2,3-Cd)PyreneGroundwater2
LeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR)Groundwater2
NickelHealth riskNickel compounds are IARC Group 1 carcinogens; inhalation exposure raises lung and nasal cancer risk. (IARC)Groundwater2
PentachlorophenolHealth riskIARC Group 1 carcinogen; wood preservative; persistent in soil and groundwater. (IARC, EPA)Soil2
Polycyclic Aromatic Hydrocarbons (Pahs)Health riskPAH class includes IARC Group 1 carcinogens (e.g., benzo[a]pyrene); long-term exposure raises cancer risk. (IARC, EPA)Soil2
TolueneHealth riskCentral-nervous-system depressant. Chronic high exposure causes hearing loss and developmental effects. (EPA, ATSDR)Groundwater2
Xylene (Mixed Isomers)Health riskEye, skin, and respiratory irritant; central-nervous-system effects from chronic exposure. (EPA)Groundwater2
ZincHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR)Groundwater2
1,1,1-TrichloroethaneHealth riskMethyl chloroform. CNS depressant; ozone-depleting substance phased out under Montreal Protocol. EPA MCL 200 µg/L. (EPA, ATSDR)Groundwater1
1,1,2-Trichloro-1,2,2-TrifluoroethaneGroundwater1
1,1-DichloroethaneHealth riskSuspected carcinogen (EPA C/likely); CNS depressant. Common at solvent-contaminated sites as a degradation intermediate. (EPA, ATSDR)Groundwater1
1,2,3,4,6,7,8,9-Octachlorodibenzo[B,E][1,4]Dioxin (Ocdd)Soil1

Showing the top 30 pairs by SEMS citation count. 33 additional (contaminant, pathway) pairs are recorded for this site.

Drinking-water linkage · SDWIS

Groundwater Systems Serving Communities Within 3 Miles

The 8 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
Pinewood Village PrivateLibby0.9 mi160GROUNDWATERIn compliance
Johnsons Mobile Home Park PrivateLibby0.9 mi35GROUNDWATERIn compliance
Emkayan Village Co Water And Sewer Dist PrivateLibby0.9 mi160GROUNDWATERUNRESOLVED
Rivers Edge Mobile Park Libby PrivateLibby0.9 mi60GROUNDWATERUNRESOLVED
Posts Trailer Court PrivateLibby0.9 mi45GROUNDWATERUNRESOLVED
High Country Park PrivateLibby0.9 mi76GROUNDWATERIn compliance
Montana Christian College PrivateLibby0.9 mi105GROUNDWATERIn compliance
Libby Creek Mobile Park Llc-Unapproved PrivateLibby0.9 mi35GROUNDWATERIn compliance

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

Within 1 mile of this site (2 Census block groups, population-weighted demographics): a population of 1,787. Why we surface this →

POPULATION SHARE
47.3%

Low-income

POPULATION SHARE
10.6%

People of color

POPULATION SHARE
4.9%

Under age 5

POPULATION SHARE
32.0%

Over age 64

Source: Census ACS 2018-2022 block-group demographics, population-weighted across the 1-mile buffer around this site (from USEPA-clone/EJAM-open blockgroupstats). 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.