Highway 3 PCE

Overview

Downtown Le Mars, Iowa sits atop a plume of tetrachloroethene (PCE) and trichloroethene (TCE), two chlorinated solvents linked to dry cleaning and metal degreasing operations. The contamination traces back to historic dry cleaning work at 18 Plymouth Street SE and was discovered in April 2008. The U.S. EPA added the site to the Superfund National Priorities List (NPL) in September 2022, making it eligible for federal cleanup funding and oversight.

PCE has an ether-like odor and was widely used in dry cleaning. TCE is a colorless liquid with a sweet odor, used to degrease metal parts and in paint removers. Both solvents have moved into soil, groundwater, and the air inside nearby buildings. EPA sampled groundwater, private wells, and indoor air at homes and businesses to gauge exposure risks. Human exposure is currently under control based on EPA assessments, which found no unacceptable exposure pathways. Groundwater migration, however, is not yet fully characterized because data collection is still underway.

Before the formal remedial investigation began, EPA ran two removal actions to reduce immediate risks. The first ran from August 2013 through August 2021 and included installing vapor mitigation systems in 20 downtown buildings. A second removal action ran from April 2021 to April 2022. During that period, about 690.4 tons of contaminated soil were excavated and trucked to a landfill, and sodium permanganate was applied to treat remaining contamination in the ground. Indoor air sampling in 2024 confirmed the vapor systems are working as designed.

The site is now in the Remedial Investigation and Feasibility Study (RI/FS) phase, which evaluates site conditions and develops long-term cleanup options. Field work began in February 2024. Twenty-one permanent groundwater monitoring wells were installed between July and November 2025, and quarterly groundwater sampling started in November 2025 and will continue through November 2027. A formal cleanup remedy has not yet been selected, and construction of a permanent fix has not begun. The City of Le Mars restricts new private wells in the area, and institutional controls limit incompatible land uses such as residential development.

Community members will have a formal chance to weigh in during the Proposed Plan phase, tentatively scheduled for mid-2028, when EPA will present its preferred cleanup approach and accept public comments. Before then, residents can access free help through the Technical Assistance Services for Communities program, which connects communities with independent scientists and engineers at no cost. Qualified groups can also apply for Technical Assistance Grants of up to $50,000 to hire their own technical advisor. Site documents are available at the Le Mars Public Library, located at 46 1st Street SW, and can be requested by calling 712-546-5004.