The Velsicol Chemical Corp. Marshall Plant covers 420 acres near Marshall in east-central Illinois. Pesticide and petroleum chemical manufacturing contaminated the site's soil, sediment, groundwater, and surface water. The site was added to the Superfund National Priorities List (NPL) in September 1983, and manufacturing stopped in 1988.
EPA identified more than 50 contaminants of concern across the site. These include volatile organic compounds such as benzene, chloroform, and toluene, as well as pesticides including chlordane, heptachlor, and alpha-chlordane. Polycyclic aromatic hydrocarbons (PAHs), heavy metals including lead, and other chemicals such as hexachlorocyclopentadiene were also found. EPA determined these substances pose an unacceptable risk to human health and the environment based on exposure potential and the types and amounts found.
After Velsicol declined to conduct required studies, the Illinois EPA took the lead in 1985 with EPA support. Field investigations ran from 1986 through 1987. EPA selected cleanup methods that included excavating contaminated soil and sediment, installing engineered caps, and running a pump-and-treat groundwater collection system using recovery trenches, collection drains, and reinjection wells. EPA, Velsicol, and the State of Illinois signed a Consent Decree in September 1989 to carry out this work. Physical construction was completed by the mid-1990s. The sources note slightly different completion dates, with one stating May 1995 and another stating September 1994 for construction completion.
The site is now in the Operations and Maintenance phase. Human exposure is under control, and groundwater migration is stabilized with no unacceptable discharge to surface water. All cleanup goals for current and anticipated future land uses have been met, and land-use restrictions are in place. The site was designated as ready for anticipated reuse in September 2010. EPA has conducted regular five-year reviews, with the most recent completed in April 2023. A partial deletion from the NPL is estimated between August and October 2026, and the next five-year review is estimated for 2028.
Community members with questions can contact EPA's Community Involvement Coordinator or Remedial Project Manager.
