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

Rocky Flats Plant (Usdoe)

This site is currently on the EPA Superfund National Priorities List and remains under federal cleanup oversight. Most-cited contaminant of concern: 2,3,7,8-Tetrachlorodibenzo-P-Dioxin (Tcdd).

Hwy 93 Between Golden&Boulder, Golden, Colorado · ZIP 80402 · EPA ID CO7890010526

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
2,3,7,8-Tetrachlorodibenzo-P-Dioxin (Tcdd)Soil1
Americium-241Health riskIARC Group 1 carcinogen (alpha emitter, half-life ~432 yr for Am-241); produced in nuclear reactors and weapons. (IARC, EPA)Soil1
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)Soil1
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)Soil1
Plutonium-239Health riskIARC Group 1 carcinogen (alpha emitter, half-life ~24,000 yr); bone- and lung-seeking; legacy of nuclear weapons production. (IARC, EPA)Sediment1
Plutonium-239Health riskIARC Group 1 carcinogen (alpha emitter, half-life ~24,000 yr); bone- and lung-seeking; legacy of nuclear weapons production. (IARC, EPA)Soil1
Plutonium-239/240Soil1
Plutonium-240Sediment1
Plutonium-240Soil1
Vanadium, Metal And/Or AlloySoil1
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

Jefferson County, Colorado (no Census block groups within 1 mile and no host city — falling back to containing county): a population of 580,519. Why we surface this →

POPULATION SHARE
6.7%

Low-income

POPULATION SHARE
23.5%

People of color

POPULATION SHARE
5.3%

Under age 5

POPULATION SHARE
17.1%

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.