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Superfund / NPL site · EPA Superfund SEMS through latest publishNPL FinalFEDERAL FACILITY

Hanford 300-Area (Usdoe)

This site is currently on the EPA Superfund National Priorities List and remains under federal cleanup oversight. Most-cited contaminant of concern: Cobalt-60.

300 Area, Benton County, Washington · ZIP 99352 · EPA ID WA2890090077

See Benton 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
Cobalt-60Health riskGamma emitter (half-life ~5.3 yr); used in industrial radiography and cancer therapy; legacy contaminant at federal sites. (EPA)Soil3
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)Soil3
Uranium-235Health riskIARC Group 1 carcinogen; chemical kidney toxicity exceeds the radiological risk at most environmental levels. EPA MCL 30 µg/L total uranium. (IARC, EPA)Soil3
Uranium-238Health riskIARC Group 1 carcinogen; chemical kidney toxicity exceeds the radiological risk at most environmental levels. EPA MCL 30 µg/L total uranium. (IARC, EPA)Soil3
Americium-241Health riskIARC Group 1 carcinogen (alpha emitter, half-life ~432 yr for Am-241); produced in nuclear reactors and weapons. (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
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)Soil2
ChryseneSoil2
Cis-1,2-DichloroetheneHealth riskTCE biodegradation intermediate. EPA MCL 70 µg/L; lower toxicity than parent solvents but commonly co-occurs in groundwater plumes. (EPA)Groundwater2
LeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR)Soil2
Plutonium-238Health riskIARC Group 1 carcinogen (alpha emitter, half-life ~24,000 yr); bone- and lung-seeking; legacy of nuclear weapons production. (IARC, EPA)Soil2
TrichloroetheneHealth riskTCE. IARC Group 1 carcinogen — kidney cancer; suspected liver cancer and non-Hodgkin lymphoma. EPA MCL 5 µg/L; common DNAPL groundwater plume contaminant. (IARC, EPA, ATSDR)Groundwater2
TritiumHealth riskHydrogen-3 (beta emitter, half-life ~12.3 yr); travels with water and is hard to remove from groundwater. EPA MCL 20,000 pCi/L. (EPA)Groundwater2
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)Groundwater2
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)Soil2
1,1,1-TrichloroethaneHealth riskMethyl chloroform. CNS depressant; ozone-depleting substance phased out under Montreal Protocol. EPA MCL 200 µg/L. (EPA, ATSDR)Soil1
1,2-Dichloroethene (Cis And Trans Mixture)Soil1
1,2-Ethanediol (Ethylene Glycol)Soil1
2-Butanone (Methyl Ethyl Ketone)Soil1
4-Methyl-2-Pentanone (Methyl Isobutyl Ketone)Soil1
Alpha GrossGroundwater1
Americium-241Health riskIARC Group 1 carcinogen (alpha emitter, half-life ~432 yr for Am-241); produced in nuclear reactors and weapons. (IARC, EPA)Debris1
Americium-241Health riskIARC Group 1 carcinogen (alpha emitter, half-life ~432 yr for Am-241); produced in nuclear reactors and weapons. (IARC, EPA)Solid Waste1
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)Soil1
Aroclor 1016Health 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)Soil1
Aroclor 1221Soil1
Aroclor 1232Health 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)Soil1
Aroclor 1242Health 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)Soil1
Aroclor 1248Health 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)Soil1
Aroclor 1254Health 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)Soil1

Showing the top 30 pairs by SEMS citation count. 79 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 · ACS 2018-2022 block-group demographics

Who Lives Near This Site

Benton County, Washington (no Census block groups within 1 mile and no host city — falling back to containing county): a population of 207,560. Why we surface this →

POPULATION SHARE
10.5%

Low-income

POPULATION SHARE
32.6%

People of color

POPULATION SHARE
8.0%

Under age 5

POPULATION SHARE
15.4%

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.