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

Castle Air Force Base (6 Areas)

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

Castle Afb, Merced, California · ZIP 95342 · EPA ID CA3570024551

See Merced 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
BenzeneHealth riskIARC Group 1 carcinogen. Long-term inhalation causes leukemia and bone-marrow disorders. (IARC, EPA)Groundwater4
ChloroformGroundwater4
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)Groundwater4
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)Groundwater4
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)Groundwater4
BenzeneHealth riskIARC Group 1 carcinogen. Long-term inhalation causes leukemia and bone-marrow disorders. (IARC, EPA)Soil3
Carbon TetrachlorideHealth riskIARC Group 2B possible carcinogen; liver toxic. EPA MCL 5 µg/L. Banned for most uses since 1986. (IARC, EPA)Groundwater3
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)Soil3
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)Soil3
1,1-DichloroetheneHealth riskVinylidene chloride; IARC Group 3 (inadequate evidence in humans) but liver toxic in animal studies; common TCE/PCE biodegradation product. (IARC, EPA)Groundwater2
1,2,4-TrimethylbenzeneHealth riskEye, skin, and respiratory irritant; high exposure causes nervous-system effects. (ATSDR)Soil2
1,2-DichloroethaneHealth riskIARC Group 2B possible carcinogen; liver and kidney toxic. EPA MCL 5 µg/L. (IARC, EPA)Groundwater2
1,4-DichlorobenzeneHealth riskIARC Group 2B possible carcinogen; common in mothballs and air fresheners. EPA MCL 75 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
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
Bis(2-Ethylhexyl)PhthalateGroundwater2
CadmiumSoil2
ChloromethaneGroundwater2
LeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR)Soil2
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)Soil2
TolueneHealth riskCentral-nervous-system depressant. Chronic high exposure causes hearing loss and developmental effects. (EPA, ATSDR)Groundwater2
TrichlorofluoromethaneSoil2
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)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
1,1-DichloroethaneHealth riskSuspected carcinogen (EPA C/likely); CNS depressant. Common at solvent-contaminated sites as a degradation intermediate. (EPA, ATSDR)Groundwater1
1,1-DichloroetheneHealth riskVinylidene chloride; IARC Group 3 (inadequate evidence in humans) but liver toxic in animal studies; common TCE/PCE biodegradation product. (IARC, EPA)Soil1
1,2,3,4,6,7,8,9-Octachlorodibenzo[B,E][1,4]Dioxin (Ocdd)Soil1
1,2,3,4,6,7,8-Heptachlorodibenzo[B,E][1,4]Dioxin (Hpcdd)Soil1

Showing the top 30 pairs by SEMS citation count. 68 additional (contaminant, pathway) pairs are recorded for this site.

Drinking-water linkage · SDWIS

Groundwater Systems Serving Communities Within 3 Miles

The 1 system 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
City Of Atwater MunicipalAtwater2.1 mi29,479GROUNDWATERIn 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

Merced County, California (no Census block groups within 1 mile and no host city — falling back to containing county): a population of 282,290. Why we surface this →

POPULATION SHARE
18.5%

Low-income

POPULATION SHARE
74.8%

People of color

POPULATION SHARE
7.9%

Under age 5

POPULATION SHARE
11.4%

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.