Region 8

Colorado Smelter

Colorado Smelter site location map Site Type: Final NPL
City: Pueblo
County: Pueblo
Street Address: Between Interstate 25 and S. Santa Fe Avenue
ZIP Code: 81006
EPA ID: CON000802700
Congressional District: 3

What's New?

Updated August 2015

Join us for the Community Advisory Group meeting

Tuesday, September 8, 2015
5:30 to 7:30 p.m.

Steelworks Museum of Industry & Culture
215 Canal Street
Pueblo, Colorado 81004

Colorado Smelter added to the National Priorities List

On December 11, 2014, EPA added the former Colorado Smelter to the National Priorities List (NPL) of Superfund sites. Superfund is the federal program that investigates and cleans up the most complex, uncontrolled or abandoned hazardous waste sites to protect public health and the environment.

EPA accepted comments from the public on the NPL proposal during the 60-day public comment period, which closed on July 11, 2014. After reviewing and responding to all comments in a responsiveness summary, EPA published notification in the Federal Register officially adding the Colorado Smelter site to the NPL.

View the Final Rule on »

  • EPA and CDPHE team will continue to reach out to community members, local officials and other stakeholders to explain the benefits of the site being placed on the National Priorities List (NPL).
  • EPA and CDPHE will continue to respond to questions and comments.
  • With community support the site has been added to the NPL.
  • Now that the site has been added to the NPL, EPA and CDPHE will continue to work with the community to keep them involved and informed throughout the Superfund process.

EPA and the Colorado Department of Public Health and Environment (CDPHE) completed a site assessment that revealed elevated levels of lead and arsenic in residential soils and large slag piles in the vicinity of the former Colorado Smelter. The results indicated a comprehensive cleanup is necessary to reduce health risks for current and future residents. EPA and CDPHE met with city and county officials, community groups, interested stakeholders and neighbors to understand the problems and risks and to gain support for listing on the National Priorities List (NPL).

Based on the size, complexity and anticipated costs, the best program to undertake the cleanup is the CERCLA (more commonly known as Superfund) National Priorities List. Cleaning up the remaining slag and neighborhood soils will result in reduced public health risks, can have a positive impact on property values and can benefit community and neighborhood revitalization efforts.

This page will help guide you through the process of Superfund, to use its common name, and the process of placing a site on the National Priorities List. There are many questions around this issue and many unknowns. We will try to break this process down into steps to help you grasp small pieces at a time rather than the whole thing at once. A one-page fact sheet illustrating these steps is available in Site Documents below. This will help you visualize that we are at the very beginning of this process. EPA will continue to keep the community informed as we move through this process. We will use this Web page to provide updates, announce meetings and events that will occur in the near future, and highlight other news we want to share with you.

We want to keep you informed, but also to hear your specific concerns and questions. See the Contacts section below for the names of both EPA and CDPHE representatives you may contact.

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Site Description

map of area of interest
Approximate area of interest

Pueblo was once home to five ore smelters and one steel mill. The Colorado Smelting Company smelter (also known as Colorado Smelter, Boston Smelter, Boston & Colorado Smelter, and Eilers Smelter) began operating in 1883. It was constructed on a mesa and dumped waste slag into a ravine between Santa Fe Avenue and the Denver & Rio Grande railroad tracks. The smelter operated eight blast furnaces, two calcining furnaces, one fusing furnace and twenty kilns. The Colorado Smelter was merged into the American Smelting and Refining Company (ASARCO) in 1899 and closed in 1908.

The potential for contamination at the Colorado Smelter site was discovered during an earlier inspection of the Santa Fe Bridge Culvert site, which began a series of investigations in the early 1990s and continues today. In 2010, CDPHE conducted a focused site inspection of properties surrounding the Colorado Smelter; this study determined that areas of elevated lead and arsenic exist, which pose a threat to current and future residents. Additional sampling will help determine the type and scope of cleanup activities.

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Potential Site Risk

Media Affected Contaminants Source of Contamination
slag pile and residential soil arsenic and lead smelting activities

EPA considers lead and arsenic to be hazardous substances. Both have been detected at elevated levels in residential yards around the Colorado Smelter neighborhood. Both substances can cause a variety of health problems to people who are exposed to them. Exposure to lead may cause nervous system damage, anemia, brain damage, or in extreme cases, even death. Children are especially susceptible to the toxic effects of lead. Exposure to arsenic can also cause a variety of health problems; arsenic is a known carcinogen.

EPA Grant to Pueblo City-County Health Department

In the spring of 2014 the Pueblo City-County Health Department applied for a Superfund grant from EPA. To date the local health department has been awarded $195,000 from the Hazardous Substance Response Fund for Lead Characterization and Risk Reduction through education activities. The local health department has been actively working on the grant by taking required training, developing outreach materials, preparing for indoor lead characterization, and planning an outreach education event in 2015. Local health department staff are regularly participating in the community advisory group meetings to better understand community education and information needs.

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Sampling Results

In June 2010, CDPHE sampled the remains of the former Colorado Smelter, which consists of slag piles, soils in nearby residential yards and a limited number of surface water and sediment samples.

The slag pile samples contained elevated concentrations of lead and arsenic. The approximately 700,000-square-foot slag pile is located in a ravine and forms a 30-foot high escarpment that extends approximately 1,275 feet along the Denver & Rio Grande Railroad tracks located between Santa Fe Avenue and Interstate 25 (I-25) south of the Arkansas River. This location can result in residents being exposed to elevated levels of arsenic and lead through the soil pathway or through the air pathway via windblown dirt.

Sediment samples taken onsite showed elevated lead and arsenic levels. Samples were taken of water seeping to the surface of the Colorado Smelter that showed elevated levels of lead and arsenic as well as cadmium, copper, manganese, selenium and zinc. Based on samples it appears unlikely that the site would have a measurable impact on the Arkansas River. Any discharge from the site that reaches the river would likely be substantially diluted. In addition to slag pile contaminants, emissions from the smelting operations often contain metals such as lead and arsenic. Samples were evaluated by comparing them to three times the highest background concentrations and available screening levels or benchmarks. Forty-seven residences were sampled; of these, five indicated levels of arsenic and lead that were greater than three times background and exceeded EPA’s national screening guidelines for these contaminants. An additional 10 residents had sampling results with only the elevated lead levels. More sampling will need to be done to determine the full nature and extent of contamination, as well as the risks to human health.

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Next Steps

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Site Documents

Fact Sheets / Hojas informativas

Recommended Practices for Safe Gardening: Ways to Reduce Incidental Soil Ingestion and Inhalation, August 2012

Recommended Practices for Safe Consumption of Homegrown Vegetables: Ways to Reduce Dietary Arsenic and Lead Ingestion, August 2012

Consent for Access | Consentimiento para acceso, October 2014

Tips to Protect Your Health | Maneras de proteger su salud, November 2013

ATSDR Health Information | ATSDR Información sobre la salud, November 2013

Sampling and Cleanup | Toma de muestras y limpieza, September 2012/3

Property Values and Institutional Controls | Valores de las propiedades y controles institucionales, September 2012/3

Community Involvement

Community Involvement Plan, April 2015

Technical Assistance Needs Assessment Recommendations, April 2015

Community Advisory Group meeting summaries

Presentations to the Community Advisory Group

Milestones and timelines of Superfund activities at Colorado Smelter, February 2015

NPL Listing

Federal Register notice of final listing on the National Priorities List (NPL), December 11, 2014

Federal Register notice of proposed listing on the National Priorities List (NPL), May 12, 2014

Steps in the Superfund and NPL listing process, May 2012

Technical Documents

Analytical Results Report, June 22, 2011

Sample and Analysis Plan, May 27, 2010

Preliminary Assessment, April 28, 2008

Earlier Studies of the Santa Fe Bridge Culvert and Boston Smelter

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Sabrina Forrest
NPL Coordinator
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street
Denver, CO 80202-1129
800-227-8917, ext. 312-6484 (toll free Region 8 only)

Chris Wardell
Community Involvement Coordinator
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street (OC)
Denver, CO 80202-1129
800-227-8917 ext. 312-6062 (toll free Region 8 only)

Site Information Repository:

Pueblo City County Library
Rawlings Branch
100 East Abriendo Ave.
Pueblo, CO 81004
Mon.–Thu. 9 a.m.–9 p.m.
Fri.–Sat. 9 a.m.–6 p.m.
Sun. 1–5 p.m.


Alissa Schultz
Environmental Protection Specialist II/Project Manager
Colorado Department of Public Health and Environment
4300 Cherry Creek Drive South
Denver, Colorado 80246-1530

Jeannine Natterman
State Community Involvement Coordinator
Colorado Department of Public Health and Environment
Hazardous Materials and Waste Management Division
4300 Cherry Creek Drive South
Denver, CO 80246-1530
888-569-1831 ext. 3303 (toll-free)

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The following links exit the site Exit

Agency for Toxic Substances and Disease Registry

Colorado Department of Public Health and Environment

Pueblo City-County Health Department

PuebloCAREs Community Action for a Renewed Environment

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