monsanto chemical co. (soda springs plant)

HWY 34, 2 MI N OF CY

The operating area of the Monsanto Chemical Company (Soda Springs Plant) encompasses 540 acres and processes locally mined phosphate ore to produce elemental phosphorus. Surrounding the operating area are approximately 260 acres of buffer properties. All 800 acres (540 acres in the operating area and 260 acres in the buffer properties) have institutional controls in place to prevent future land-use that could result in exposure to hazardous constituents. The elemental phosphorous plant consists of over a dozen administrative and processing buildings plus ore piles, slag piles, by-product materials, surface impoundments and a waste landfill. The site, formerly agricultural land, was purchased by Monsanto in 1952. Ore is stockpiled on-site prior to being processed for introduction into electric arc furnaces along with coke and silica. All process waters, with the exception of non-contact cooling water, are held and treated on site and then reused. The non-contact cooling water is discharged from the site to Soda Creek, which is used in agricultural irrigation. Land use in the vicinity of the Monsanto facility is primarily industrial and agricultural. The plant is staffed with about 400 employees, and 3,300 residents live within 3 miles of the site. Most residents' water is supplied by the City of Soda Springs from springs unaffected by the plant. The closest surface water is Soda Creek, located approximately 2,000 feet west of the facility. Some nearby residents depend on domestic wells, but none are known to be in use for drinking water downgradient of the site. EPA completed the first five-year review for the Monsanto Chemical Company (Soda Springs Plant) on September 30th, 2003. Below is the protectiveness statement included in the five-year review report: "The remedy at the Monsanto Chemical Co. (Soda Springs Plant) currently protects human health and the environment because all known groundwater and soil exposure pathways have been restricted through institutional controls or other means. However, in order for the remedy to be protective in the long-term, the following actions need to be taken: 1) the Lewis well and property needs to be evaluated for institutional controls; 2) Monsanto needs to submit a plan for upgrading their wind dispersal program and for evaluating in the short term those localized areas where increased 226Ra soil concentrations have been observed; and, 3) the U.S. Environmental Protection Agency (EPA) needs to reevaluate during the next five-year review whether the monitored natural attenuation remedy underneath the operating area is proceeding as intended in the decision documents." Site Responsibility: This site is being addressed through federal and potentially responsible parties' actions.

Hazardous Ranking Score

55 / 100

A score of 28.5 or higher qualifies a site for the Superfund National Priority List.

Regional Contact

Region 10
Phone: (800) 424-4372

Contact Region



Site Inspection
Preliminary Assessment
Final Listing On NPL

Contaminants & Health Effects

      Endocrine Disrupter
      Reproductive Toxin
      Persistent, bioaccumulative and toxic


        African American
        American Indian and Alaska Native
        Native Hawaiian


        People living
        within a 1 mile radius


        Average Income


        Occupied homes

        Potentially Responsible Parties

        Similar Sites

        Add Story


        No stories have been submitted for this site.