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

Harbor Island (Lead)

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

Mouth Of Duwamish River, Seattle, Washington · ZIP 98134 · EPA ID WAD980722839

See King 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)Sediment5
MercuryHealth riskNeurotoxin. Methylmercury bioaccumulates up the food chain and damages the developing nervous system. (EPA, ATSDR)Sediment5
Polychlorinated Biphenyls (Pcbs)Health riskPCBs. IARC Group 1 carcinogen; immune, reproductive, and neurological effects; bioaccumulate in fish and breast milk. Banned in 1979; persist as legacy contamination. (IARC, EPA)Sediment5
ZincHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR)Sediment5
LeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR)Sediment4
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)Soil3
CopperHealth riskInhaled copper fumes cause metal-fume fever; chronic ingestion above EPA's 1.3 mg/L action level damages the liver. (EPA)Sediment3
LeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR)Soil3
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)Soil3
BenzeneHealth riskIARC Group 1 carcinogen. Long-term inhalation causes leukemia and bone-marrow disorders. (IARC, EPA)Groundwater2
BenzeneHealth riskIARC Group 1 carcinogen. Long-term inhalation causes leukemia and bone-marrow disorders. (IARC, EPA)Soil2
CadmiumSediment2
CopperHealth riskInhaled copper fumes cause metal-fume fever; chronic ingestion above EPA's 1.3 mg/L action level damages the liver. (EPA)Groundwater2
EthylbenzeneHealth riskIARC Group 2B possible carcinogen; eye and respiratory irritant. (IARC)Soil2
LeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR)Groundwater2
P,P'-DdtHealth riskIARC Group 2A probable carcinogen; persistent bioaccumulator; banned in the US in 1972 but residues persist in soil and sediment. (IARC, EPA)Sediment2
Polychlorinated Biphenyls (Pcbs)Health riskPCBs. IARC Group 1 carcinogen; immune, reproductive, and neurological effects; bioaccumulate in fish and breast milk. Banned in 1979; persist as legacy contamination. (IARC, EPA)Soil2
TetrachloroetheneHealth riskPCE / 'perc'. IARC Group 2A probable carcinogen; central-nervous-system effects; common dry-cleaning solvent and DNAPL plume contaminant. EPA MCL 5 µg/L. (IARC, EPA)Groundwater2
TolueneHealth riskCentral-nervous-system depressant. Chronic high exposure causes hearing loss and developmental effects. (EPA, ATSDR)Soil2
Total Petroleum Hydrocarbons (Tph)Soil2
Xylene (Mixed Isomers)Health riskEye, skin, and respiratory irritant; central-nervous-system effects from chronic exposure. (EPA)Soil2
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
1,2-DihydroacenaphthyleneSediment1
1,4-DichlorobenzeneHealth riskIARC Group 2B possible carcinogen; common in mothballs and air fresheners. EPA MCL 75 µg/L. (IARC, EPA)Sediment1
2,4-DimethylphenolSediment1
2-MethylnaphthaleneSediment1
9H-FluoreneSediment1
Alpha-HexachlorocyclohexaneHealth riskLindane. IARC Group 1 carcinogen (added 2015); banned for agricultural use in the US in 2007. (IARC, EPA)Fish Tissue1
Alpha-HexachlorocyclohexaneHealth riskLindane. IARC Group 1 carcinogen (added 2015); banned for agricultural use in the US in 2007. (IARC, EPA)Sediment1

Showing the top 30 pairs by SEMS citation count. 72 additional (contaminant, pathway) pairs are recorded for this site.

Drinking-water linkage · SDWIS

Groundwater Systems Serving Communities Within 3 Miles

The 12 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
Hot Springs Court PrivateSeattle2.8 mi55GROUNDWATERIn compliance
Montipark Llc PrivateSeattle2.8 mi60GROUNDWATERIn compliance
Hidden Village Mhp, Llc PrivateSeattle2.8 mi66GROUNDWATERIn compliance
Country Homes Mobile Park PrivateSeattle2.8 mi90GROUNDWATERIn compliance
Valley Mobile Home Park PrivateSeattle2.8 mi120GROUNDWATERIn compliance
Pcm Aria Marion Llc PrivateSeattle2.8 mi230GROUNDWATERIn compliance
Brunswick Hills Mhp PrivateSeattle2.8 mi50GROUNDWATERIn compliance
Golf Mhp PrivateSeattle2.8 mi60GROUNDWATERIn compliance
River Village Mhp PrivateSeattle2.8 mi40GROUNDWATERIn compliance
Cherrywood Mobile Home Manor PrivateSeattle2.8 mi120GROUNDWATERUNRESOLVED
Majestic Oaks Water System PrivateSeattle2.8 mi28GROUNDWATERIn compliance
Ravenwing Ranch PrivateSeattle2.8 mi250GROUNDWATERIn 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 (1 Census block groups, population-weighted demographics): a population of 1,168. Why we surface this →

POPULATION SHARE
11.4%

Low-income

POPULATION SHARE
43.0%

People of color

POPULATION SHARE
6.8%

Under age 5

POPULATION SHARE
4.7%

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.