The Colorado Smelter operated for 25 years, from 1883 until 1908 and was located in south Pueblo, just south of the Arkansas River at the south end of Santa Fe Avenue.  It was constructed in a large ravine between what is now Santa Fe Avenue and Interstate 25.  The owners of the Madonna Mine, located in the mountains far to the west in Monarch, Colorado, built the Colorado Smelter to smelt the extracted silver-lead ore in a cost-effective manner. The ore from the Madonna mine processed at the Colorado Smelter contained 30 percent lead by weight (Colorado Department of Public Health and Environment 2008). 

Site inspection, sampling and historic information identified a couple of areas of contamination associated with the Colorado Smelter

  1.  Slag pile that covers 25 acres (728,171 square feet) and is up to 30 feet high in place.
  2.  Lead contamination of nearby residential soils from past air emissions and run-off (Colorado Department of Public Health and Environment 2008).

Access to the slag pile is unrestricted except for fencing at Benedict Park, which borders the slag pile.  However, local authorities report that the fencing is often cut, and children access the slag pile from the park to climb and ride mountain bikes. Local authorities also report indications that homeless people access the slag pile. 

Sampling investigations by the U.S. Environmental Protection Agency (U.S.EPA) and the State of Colorado in 1992, 1994, 1995, 2008, and 2010 found lead levels up to 26,500 mg/kg in the slag pile and up to 4,900 mg/kg of lead in 30 residential soils.

Information about the Colorado Smelter Site in Pueblo.

Colorado Smelter Study Area Map

The Pueblo Department of Public Health and Environment received a grant from the U.S. Environmental Protection Agency to provide lead testing and risk reduction for the residents in the Superfund Study Area.

The Colorado Smelter Community Advisory Group (CAG):


Meets on the second Tuesday of each month
    NeighborWorks Southern Colorado, 1241 E Routt Ave, Pueblo, CO 81004


For more information/Para mas informacion:

V. Jasmin Guerra

USEPA Region 8

Community Involvement Coordinator

Work: 303-312-6508

1-800-227-8917 ext 6508



For additional copies or information on the ATSDR Exposure Investigation around the Colorado Smelter site in Pueblo, Colorado, contact Environmental Health Division (719) 583-4307.