Site Progress

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Current Site Status

EPA divided the site into two operable units (OUs): OU1 (Community Properties) and OU2 (Former Smelter Area).

For OU1, EPA finished cleaning homes under the current cleanup level in 2025. EPA is still sampling commercial properties. Parks, schools and city properties have been tested. A small area with children’s play equipment at Benedict Park was cleaned; no additional work is planned at this time. For OU2, EPA is sampling the former smelter area and expects to propose a cleanup plan in 2028 (subject to change).

Operable Unit 1

Operable Unit 1 includes homes, businesses and community properties like parks and schools. There are approximately 2,070 residential properties and between 150-200 commercial properties in Operable Unit 1. 

In February 2025, EPA finished cleaning homes under the current cleanup level. Commercial properties are being investigated and will be cleaned after a site-specific cleanup goal is developed. EPA investigated parks, schools, city properties and alleys. EPA cleaned an area of Benedict Park due to high arsenic levels, and no additional work is planned at this time.

Boundaries of the Colorado Smelter Site and Area Neighborhoods
Map of Colorado Smelter residential site. Includes the neighborhoods of the Grove, Eilers and parts of Bessemer.  Colorado Smelter Site and Area Neighborhoods - Residential Study Area boundaries.

Residential Properties

EPA finished testing and cleaning soil and indoor dust at homes under the current cleanup goal in 2025. This has drastically reduced the number of people who may be exposed to lead and arsenic contamination from the former Colorado Smelter. EPA completed work at the following properties that provided access:

  • Soil sampling
    • 1,989 homes (3% denied access) 
  • Soil cleanups and restoration
    • 813 homes (5% denied access) 
  • Indoor dust sampling
    • 1,818 homes (8.1% denied access  
  • Indoor dust cleanups
    • 568 homes (3% denied access) 

Residential Lead Guidance

Based on the January 2024 Updated Lead Guidance, the EPA is evaluating the risks from lead in soils to sensitive populations. This analysis will include compiling available site data to determine the potential presence and extent of lead-contaminated soils. Lead can pose health risks to sensitive populations, especially children under 7 years old and pregnant or nursing women. The process to implement the Updated Residential Lead Guidance will involve additional planning, data gathering, risk assessment and funding requests. EPA will coordinate with our state partners and request public feedback on our proposed, revised cleanup goals. 

While implementing the revised cleanup goals may take years to complete, the EPA and the Colorado Department of Public Health and the Environment will share information on planned activities and results as they become available. In the meantime, and out of an abundance of caution, if you live near the Colorado Smelter Superfund Site, the EPA recommends you have your children tested for lead annually; especially those under 7 and if the soil at your property was not replaced previously. Additionally, you can take some simple actions to limit exposure to potential lead contamination in soils, including: 

  • Maintaining yards and other soil cover;   
  • Washing hands, especially children’s, after handling soil, playing outside, and before meals;  
  • Making sure children eat nutritious meals high in iron and calcium;  
  • Keeping dust levels down by mopping and damp dusting regularly;   
  • Regularly changing out furnace filters; 
  • Keeping kids’ toys and play areas clean;  
  • Taking shoes off at the door and keeping pets clean;  
  • Wearing gloves while gardening; and  
  • Cleaning homegrown produce and peeling root vegetables.  

The EPA Colorado Smelter site team will communicate with residents affected by this guidance about the specific next steps the Agency will take in their community. Residents may also contact the site’s Remedial Project Manager or Community Involvement Coordinator with questions or concerns at (chan.sydney@epa.gov) or 303-241-9767 or (archer.elizabeth@epa.gov) or 720-512-1917.

Community Properties (Schools, Parks, and City Properties)

In 2017 EPA performed a cleanup at Benedict Park where the concentrations were above the current soil cleanup levels. EPA does not anticipate any additional work at this time.

Commercial Properties

EPA began sampling commercial soil in June 2023. EPA plans to develop proposed cleanup goals and a cleanup plan based on sampling results. This plan will be documented in a proposed plan and Record of Decision, both will be shared for public feedback before being adopted.
As of March 31, 2025, OU1 commercial sampling has progressed as follows:

  • Soil sampling Complete, 38%
  • Soil Sampling In Progress, 7%
  • Soil is Capped/Inaccessible, 43%
  • Denied Sampling Access, 12%

Operable Unit 2

Operable Unit 2 (OU2) is the portion of the Site where the former smelter was located. The footprint of the former smelter is approximately 49.7 acres. Approximately 16 of those acres contain large deposits of slag. 

OU2 includes:

  • commercial and industrial properties, 
  • vacant land, 
  • parks and 
  • several undeveloped areas outside of the smelter footprint.
Map of Colorado Smelter Superfund site with two operable units. The site goes north to E C St and south to Baystate Ave.
Map of Colorado Smelter Superfund site with two operable units. The site goes north to E C St and  south to Baystate Ave. Colorado Smelter Superfund Site Study Area Boundary and Operable Units labeled.

Sampling Status

EPA is currently in the remedial investigation phase at OU2. If you would like to review the sampling locations in OU2, please visit the StoryMap. EPA will develop several risk assessments during the remedial investigation to help determine appropriate cleanup goals. 

Once EPA collects sufficient data, we will evaluate what cleanup options may be effective (feasibility study). Though the area is privately owned, EPA is considering the current and reasonably anticipated future land use for the area. In 2024, EPA hosted a session to discuss the future use at OU2 (pdf) (6 pp, 1.37 MB). EPA anticipates finalizing a Record of Decision for Operable Unit 2 in 2027, although this timeline is subject to change. 

Property for Sale

Several parcels in OU2 are available for sale. EPA frequently meets with interested buyers to provide information about the status of the property and EPA’s enforcement policies. If you are interested in purchasing property in OU2, please reach out to the Remedial Project Manager for OU2, Erica Serna at (serna.erica@epa.gov) or (720) 914-3163. 

EPA has an enforcement policy stating EPA will generally not cost recover against residential property owners: Guidance: Owners of Residential Property at Superfund Sites. However, this policy does not apply to non-residential parcels in OU2. Property owners in OU2 may be held liable under Superfund law. EPA created a fact sheet with frequently asked questions for property owners in OU2 (pdf) (4 pp, 925 KB).

Unhoused Population

Unhoused individuals have been seen living in OU2. Preliminary data show lead and arsenic contamination in the soil, water, and slag in the former smelter area. Individuals living in the former smelter area face risks from direct contact with metals in the soil and water, and could breathe, drink or eat this contamination which may pose a threat to human health.

EPA is collaborating with other agencies and organizations working with the unhoused population to communicate the health risks. The best way to avoid health effects from lead and arsenic is to avoid contact with contaminated soil, slag, and water. EPA placed fencing and signs warning about the risks of living in the area. EPA also developed a fact sheet about risks in the area for those working with the unhoused population (pdf) (2 pp, 1.12 MB).

2024 City Enforcement Action

In October 2024, the City of Pueblo conducted  work under their code enforcement authority with the property owner in a portion of OU2 commonly referred to as ‘The Jungle’. The City removed vegetation and trash. When consulted prior to the action, EPA recommended best practices to the City to suppress dust and minimize disturbance of contaminated soils. 

EPA received several calls from concerned citizens about soil disturbances and dust coming off the site. EPA coordinated with the Pueblo Department of Public Health and Environment to offer free blood-lead testing to any concerned citizen or worker. EPA is resampling areas where soil was disturbed and where soil and vegetation were staged. 

Previous Work

EPA was able to expedite testing and cleaning homes at the same time to speed cleanup and reduce prolonged exposure to individuals. EPA conducted several studies based on community concerns. EPA also collaborated with the state and local health departments to provide resources for those who are exposed to contamination. Read more about EPA’s work below.

Operable Unit 1 – Community Properties 

OU1 includes homes, businesses, parks, schools, and City properties. A chronological timeline of events below: 

  • EPA began testing soil and interior dust in homes in 2015.
  • EPA documented the cleanup plan for homes in 2017 in the Interim Record of Decision (IROD) (pdf) (150 pp, 7.6 MB). 
    • The cleanup levels are:
      • Soil:
        • Lead: 350 parts per million (ppm)
        • Arsenic: 275 ppm
      • Indoor Dust:
        • Lead: 61 ppm
        • Arsenic: 61 ppm
    • The plan states for properties above the cleanup level, EPA will :
      • remove and replace contaminated soils and 
      • perform indoor dust cleanups where necessary.
  • EPA tested schools, parks, and city owned properties. Most did not need a cleanup under the 2017 cleanup level.
    • Soil tested, cleanup not needed: Strack School, Bessemer Academy School, Runyon Fields, Moynihan Park, Bessemer Park, Stauter Park, Bessemer School Park, 93 Unpaved Alleys and 2 City Parcels
    • Soil tested, cleanup complete: Benedict Park
      • EPA conducted soil cleanup at a small area below the playground equipment at this park in 2017. This cleanup area was associated with the former smelter’s main flue to remove arsenic-contamination to a depth of approximately 1 foot.
  • EPA began funding a grant with the Pueblo Department of Public Health and the Environment so residents in the Superfund site can get free blood-lead testing, and those outside can get low-cost testing. 
    • This is funded in partnership with the Colorado Department of Public Health and the Environment.
  • EPA established a the initial study area in 2017. EPA extended the study area based on adjacent properties that had heightened levels of lead and arsenic. 
  • Based on community concerns, EPA studied and tested HVAC ducts to see if they would re-contaminate homes in 2017. 
    • The duct work report (pdf) (6 pp, 3 MB) found that HVAC systems are not likely to re-contaminate homes following cleanup. However, residents can protect themselves by using best practices and changing HVAC filters every one to three months.
  • EPA completed 27 emergency indoor dust cleanings from June 2016 to July 2017 and seven additional indoor cleanups in December 2017.
  • EPA set up a Job Training Initiative to train Pueblo locals to participate in the Superfund site cleanup work in 2018. They received technical training and certificates in OSHA-10, CPR/First Aid, and 40-hr Hazardous Waste Operations and Emergency Response.
    • There were 15 graduates, 5 were hired to work on the project, one of whom worked on the cleanup for several years.
  • The study area was expanded in September 2021, adding 100 more homes. 
  • The study area was expanded again in September 2022, adding 66 more homes. 
  • EPA began testing soil at commercial properties in June 2023.
  • EPA completed the first review of the cleanup, Five-Year Review (pdf) (47 pp, 14 MB) in January 2023. The review found: 
    • The cleanup will be protective when EPA finishes cleaning soil and indoor dust at homes
    • Institutional controls will be needed for properties where contaminated soil is left in place at levels above the current cleanup goal. 
  • EPA added long term protectiveness to the residential remedy and finalized the site boundary in June 2023. 
    • This is the first step to implementing institutional controls to ensure individuals who want to dig large amounts of soil in yards within the site do not disturb or spread contamination so human health remains protected.
    • This document is called an Explanation of Significant Differences (pdf) (9 pp, 1.2 MB)
  • EPA cleaned all homes that granted access and needed cleanup under the current cleanup levels in 2025.
    • EPA cleaned over 800 yards and indoor dust at nearly 570 homes.

Operable Unit 2 – The Former Smelter Area

Colorado Smelter

Contact Us About the Colorado Smelter
Contact Us About the Colorado Smelter to ask a question, provide feedback, or report a problem.
Last updated on August 14, 2025