Superfund Information Systems: Site Profile

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About the Superfund Redevelopment Initiative

This nationally coordinated effort provides EPA and its partners with a process to return Superfund sites to productive use. Learn more at Superfund Redevelopment Initiative.

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Redevelopment at the Site

The Monsanto Chemical Co. (Soda Springs Plant) Superfund site is located outside Soda Springs, Idaho. The 800-acre site includes the 540-acre Monsanto plant operating area as well as 260 acres of buffer area in which locally mined phosphate ore is processed to produce elemental phosphorus. In 1990, EPA listed the site on the Superfund program's National Priorities List (NPL) after the identification of contamination in groundwater and soils at the site. EPA required that Monsanto place restrictions on the buffer area. In 1998, Monsanto instituted land use controls on the buffer area. Monsanto took actions to control dust emissions from source piles contaminated with radium and is investigating other materials as potential sources to groundwater. Cadmium, selenium, nitrate and fluoride contaminate groundwater. In a recent review, groundwater monitoring indicated that natural attenuation may not be occurring for some of the contaminants and that the area of groundwater contamination is larger than originally defined. Groundwater monitoring continues, and EPA is in the process of determining the need for a new groundwater cleanup approach for the site. The site continues to operate, producing elemental phosphorus for multiple uses.

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Economic Activity at the Site

As of December 2019, EPA had data on 2 on-site businesses. These businesses employed 401 people and generated an estimated $22,405,000 in annual sales revenue. View additional information about redevelopment economics at Superfund sites.

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