International Minerals & Chemicals Corp. (Terre Haute East Plant)

Overview

This 37-acre site in Terre Haute, Indiana, was contaminated during benzene hexachloride (BHC) manufacturing that took place from 1946 to 1954. BHC is a chlorinated chemical used as a pesticide. After International Minerals and Chemicals Corp. (IMC) purchased the facility in 1975, the company excavated about 18,500 cubic yards of contaminated soil and placed it under a clay cap in the northwest corner of the property. EPA added the site to the National Priorities List (NPL) in 1986. The NPL is EPA's list of the nation's most contaminated sites that need long-term cleanup attention.

The main contaminants at the site are BHC and chloroform, found in soil and groundwater. Three nearby residential wells were found to contain chloroform at unsafe levels during early sampling. Removal of the contamination source brought those levels back down to safe levels. Volatile organic compounds (VOCs) have also been identified at low levels in groundwater. Before cleanup, people could have been exposed through direct contact with contaminated soil, inhalation, or accidental ingestion of contaminated groundwater.

A remedial investigation found that BHC inside the clay-capped mound was not negatively affecting groundwater. Based on that finding, EPA chose a "No Action" remedy that called for routine cap inspections, maintaining vegetative cover on the mound, and periodic groundwater monitoring. Sources differ on when the site was deleted from the NPL, citing either February 1991 or 2001, but both agree that deletion followed decades of monitoring showing no exceedances of groundwater contamination standards. Groundwater monitoring was allowed to stop after 2010, and the site achieved Site-Wide Ready for Anticipated Use status in March 2011.

Current conditions are under control. Human exposure is no longer a concern, and groundwater migration is stabilized with no unacceptable discharge to surface water. Institutional controls remain in place to limit land use and prevent exposure to any remaining contamination in soils and groundwater. EPA's 2018 five-year review confirmed that cleanup actions continue to protect human health and the environment, and the most recent five-year review was completed in November 2023.

Community members who want to learn more about the site can review records at the Vigo County Library at One Library Square in Terre Haute. Nine key documents related to the site are also available through EPA's Superfund records system. For direct questions, the EPA Remedial Project Manager is Demaree Collier, reachable by email or phone.