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

Rocky Mountain Arsenal (Usarmy) Superfund

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

Immed N Stapleton Intl Arpt, Adams County, Colorado · ZIP 80022 · EPA ID CO5210020769

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 Contaminants Are In Rocky Mountain Arsenal (Usarmy)

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
AldrinHealth riskMetabolizes to dieldrin in the body. EPA classifies as 'probable human carcinogen'; banned in the US in 1987. (EPA, ATSDR)Soil5
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)Groundwater5
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)Soil5
BenzeneHealth riskIARC Group 1 carcinogen. Long-term inhalation causes leukemia and bone-marrow disorders. (IARC, EPA)Groundwater5
ChlordaneHealth riskIARC Group 2B possible carcinogen; neurotoxin; banned for most uses in 1988 but residues persist. (IARC, EPA)Soil5
DieldrinHealth riskIARC Group 3 (inadequate evidence) but EPA classifies as 'probable human carcinogen'; neurotoxin and persistent organic pollutant. (EPA, ATSDR)Soil5
EndrinHealth riskAcutely neurotoxic; bioaccumulator. EPA banned all uses in 1986. (EPA, ATSDR)Soil5
MercuryHealth riskNeurotoxin. Methylmercury bioaccumulates up the food chain and damages the developing nervous system. (EPA, ATSDR)Soil5
TolueneHealth riskCentral-nervous-system depressant. Chronic high exposure causes hearing loss and developmental effects. (EPA, ATSDR)Groundwater5
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)Groundwater5
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)Groundwater4
BenzeneHealth riskIARC Group 1 carcinogen. Long-term inhalation causes leukemia and bone-marrow disorders. (IARC, EPA)Soil4
IsodrinSoil4
MercuryHealth riskNeurotoxin. Methylmercury bioaccumulates up the food chain and damages the developing nervous system. (EPA, ATSDR)Groundwater4
1,1,1-TrichloroethaneHealth riskMethyl chloroform. CNS depressant; ozone-depleting substance phased out under Montreal Protocol. EPA MCL 200 µg/L. (EPA, ATSDR)Groundwater3
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)Soil3
1,2-Dibromo-3-ChloropropaneGroundwater3
1,2-DichloroethaneHealth riskIARC Group 2B possible carcinogen; liver and kidney toxic. EPA MCL 5 µg/L. (IARC, EPA)Soil3
AldrinHealth riskMetabolizes to dieldrin in the body. EPA classifies as 'probable human carcinogen'; banned in the US in 1987. (EPA, ATSDR)Groundwater3
CadmiumGroundwater3
CadmiumSoil3
Carbon TetrachlorideHealth riskIARC Group 2B possible carcinogen; liver toxic. EPA MCL 5 µg/L. Banned for most uses since 1986. (IARC, EPA)Soil3
ChloroformSoil3
ChromiumHealth riskHexavalent chromium (Cr-VI) is an IARC Group 1 carcinogen via inhalation, causing lung cancer; trivalent chromium is far less toxic. (IARC, EPA)Groundwater3
ChromiumHealth riskHexavalent chromium (Cr-VI) is an IARC Group 1 carcinogen via inhalation, causing lung cancer; trivalent chromium is far less toxic. (IARC, EPA)Soil3
Dichloromethane (Methylene Chloride)Health riskIARC Group 2A probable carcinogen; central-nervous-system depressant; banned for most consumer paint-stripper uses. (IARC, EPA)Soil3
DicyclopentadieneGroundwater3
DicyclopentadieneSoil3
DieldrinHealth riskIARC Group 3 (inadequate evidence) but EPA classifies as 'probable human carcinogen'; neurotoxin and persistent organic pollutant. (EPA, ATSDR)Groundwater3
EndrinHealth riskAcutely neurotoxic; bioaccumulator. EPA banned all uses in 1986. (EPA, ATSDR)Groundwater3

Showing the top 30 pairs by SEMS citation count. 268 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

Adams County, Colorado (no Census block groups within 1 mile and no host city — falling back to containing county): a population of 520,149. Why we surface this →

POPULATION SHARE
9.6%

Low-income

POPULATION SHARE
52.5%

People of color

POPULATION SHARE
6.6%

Under age 5

POPULATION SHARE
10.8%

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.