Superfund Site Profile

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 in south Pueblo. Waste slag was deposited in a ravine between Santa Fe Avenue and the Denver & Rio Grande railroad tracks. The owners of the Madonna Mine, located in Monarch, built the Colorado Smelter in order to smelt their extracted silver-lead ore in a cost effective manner. The Colorado Smelter operated eight blast furnaces, two calcining furnaces, one fusing furnace and twenty kilns.

The Colorado Smelting Company merged into the American Smelting and Refining Company (ASARCO) in 1899. The Colorado Smelter closed in 1908. Some of the slag was used as track ballast for the D&RG track constructed between Florence and Cañon City. In 1923, bricks from the blast furnace smoke stack were used to construct St. Mary School.

The Colorado Smelter historical footprint is bound by Santa Fe Avenue to the east, Mesa Avenue to the south, Interstate 25 to the west, and the Arkansas River to the north. The Bessemer and Eilers neighborhoods are adjacent to the former Colorado Smelter site, which now consists of building remains and an approximately 700,000-square-foot slag pile.

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, The Colorado Department of Public Health and Environment (CDPHE) conducted a focused site inspection of properties surrounding the Colorado Smelter; this study determined the presence of elevated lead and arsenic levels. These levels pose a threat to current and future residents. Additional sampling will help determine the type and scope of cleanup activities.


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