Colorado is home to 20 sites on the EPA’s National Priorities List. The EPA’s National Priorities List currently includes 20 active NPL sites in Colorado, with 24 total entries when proposed and deleted sites are included. The most hazardous site has an HRS score of 64.32 out of a maximum of 100. 1 additional site is proposed for the NPL and awaiting final listing. 3 sites have been cleaned up and removed from the list. The interactive map below shows all NPL sites in Colorado – click any marker for site details, HRS score, and a link to the EPA’s site profile.
Superfund Statistics for Colorado
| Category | Count |
|---|---|
| Active NPL Sites | 20 |
| Proposed NPL Sites | 1 |
| Deleted (cleaned up) | 3 |
| Total NPL Entries | 24 |
| Highest HRS Score | 64.32 |
| Average HRS Score (active) | 50.8 |
| EPA Region | Region 8 |
Highest-Risk Superfund Sites in Colorado
The table below lists the active NPL sites in Colorado sorted by Hazard Ranking System (HRS) score. The HRS is a 0-100 scale used by the EPA to assess the potential threat to human health and the environment. Sites scoring 28.50 or above qualify for NPL listing.
| Site Name | City / County | HRS Score | EPA ID |
|---|---|---|---|
| Rocky Flats Plant (USDOE) | Golden, Jefferson | 64.32 | CO7890010526 |
| Rocky Mountain Arsenal (USARMY) | Adams County, Adams | 58.15 | CO5210020769 |
| California Gulch | Leadville, Lake | 55.84 | COD980717938 |
| Central City, Clear Creek | Idaho Springs, Clear Creek | 51.39 | COD980717557 |
| Captain Jack Mill | Ward, Boulder | 50.56 | COD981551427 |
| Bonita Peak Mining District | San Juan County, San Juan | 50.00 | CON000802497 |
| Standard Mine | Gunnison National Forest, Gunnison | 50.00 | CO0002378230 |
| Vasquez Boulevard and I-70 | Denver, Denver | 50.00 | CO0002259588 |
| Summitville Mine | Rio Grande County, Rio Grande | 50.00 | COD983778432 |
| Colorado Smelter | Pueblo, Pueblo | 50.00 | CON000802700 |
| Lowry Landfill | Arapahoe County, Arapahoe | 48.36 | COD980499248 |
| Nelson Tunnel/Commodore Waste Rock | Creede, Mineral | 48.03 | CON000802630 |
| Eagle Mine | Minturn, Redcliff, Eagle | 47.19 | COD081961518 |
| Denver Radium Site | Denver, Denver | 44.11 | COD980716955 |
| Uravan Uranium Project (Union Carbide Corp.) | Uravan, Montrose | 43.53 | COD007063274 |
Superfund Cleanup Progress in Colorado
Colorado has made measurable progress on Superfund cleanup: 3 sites have been fully remediated and removed from the National Priorities List. The remaining 20 active sites are at various stages of investigation and cleanup. EPA cleanup timelines vary widely depending on contamination type, site complexity, and the availability of responsible parties to fund remediation.
About the Superfund Program in EPA Region 8
The Superfund program, formally known as the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), gives the EPA authority to clean up contaminated sites that pose risks to public health or the environment. Sites are assessed using the Hazard Ranking System (HRS) – a score of 28.50 or above triggers NPL listing and formal cleanup proceedings. Colorado falls under EPA Region 8, which coordinates Superfund investigations, cleanups, and community engagement for the region.
Frequently Asked Questions
How many Superfund sites are in Colorado?
Colorado has 20 active sites on the EPA National Priorities List, plus 1 proposed site awaiting final listing. Including sites that have been cleaned up and removed, the total NPL count for Colorado is 24.
What is the most contaminated Superfund site in Colorado?
Based on HRS score, the highest-risk active Superfund site in Colorado is Rocky Flats Plant (USDOE) near Golden, with an HRS score of 64.32. The HRS score reflects the site’s potential to harm human health or the environment through groundwater, surface water, soil, or air pathways.
How does the EPA decide which sites go on the Superfund list?
The EPA uses the Hazard Ranking System to score sites based on the likelihood of a release, the characteristics of the waste, and the people or environments that could be affected. Sites scoring 28.50 or higher are eligible for the National Priorities List. Once listed, sites become eligible for federally funded cleanup or enforcement against responsible parties under CERCLA.
Superfund Sites in Nearby States
Explore Superfund data for states bordering Colorado: Arizona, Kansas, Nebraska, New Mexico, Oklahoma, Utah, Wyoming. For a national overview, see the US Superfund Sites map.
