The Syntex Facility sits on 180 acres in Verona, Missouri, where the Spring River splits the property into East and West sections. The site manufactured 2,4,5-T herbicide and hexachlorophene antibacterial agent from the 1960s through the early 1970s. Both processes created dioxin and other hazardous waste by-products. EPA added the site to the Superfund National Priorities List in 1983.
Five contaminants of concern have been identified across different parts of the site. In the soil, 2,3,7,8-tetrachlorodibenzo-p-dioxin, commonly called TCDD, is the primary concern. In groundwater and surface water, four chemicals are present: chlorobenzene, dichloromethane (also called methylene chloride), ethylbenzene, and xylene. Contamination also reached fish and sediment in the downstream Spring River.
Cleanup was organized into operable units. Dioxin-contaminated soils were excavated and incinerated between 1988 and 1990, with caps and vegetative covers installed afterward. Equipment disposal finished by 1996, and construction across the site was complete by September 1998. For groundwater, a 1993 decision called for monitoring with no further active cleanup, as off-site contamination met EPA standards at that time. EPA's 2022 five-year review found the soil and groundwater remedies remain protective of human health and the environment. However, a half-mile-long plume of 1,4-dioxane-contaminated groundwater was discovered extending from the BCP Ingredients facility to the north. The source and full extent of that plume have not been determined. In June 2023, BCP Ingredients and Syntex Agribusiness entered an agreement with EPA to investigate the 1,4-dioxane contamination under a new cleanup area called Operable Unit 3.
The East Area is now owned and operated by BCP Ingredients Inc., which employed 59 people on-site as of December 2024. Environmental covenants restrict groundwater use across both areas and bar the West Area from residential, agricultural, or recreational use. Human exposure is currently considered under control, with no unacceptable exposure pathways identified. Groundwater migration status remains uncertain because the full extent of contaminated groundwater has not yet been established. The site has not been deleted from the National Priorities List.
Community members can attend public meetings or contact EPA directly with questions. EPA held a public meeting in Verona on July 19, 2023, to update residents and discuss environmental concerns in the area. The next five-year review is estimated between September and November 2027. Questions can be directed to the EPA's Community Involvement Coordinator or the site's Remedial Project Manager.
