The Highway 3 PCE site was discovered in April 2008 during an investigation conducted for the nearby Le Mars Coal Gas Plant site. Groundwater sampling identified the presence of tetrachloroethene (PCE) and its breakdown products. Those contaminants were determined to not be associated with the Le Mars Coal Gas Plant site.
Since discovery of the groundwater contamination, EPA has been investigating the site to identify threats posed to human health and the environment, as well as to determine the extent of contamination. In 2009, the EPA completed a Pre-Comprehensive Environmental Response, Compensation, and Liability Information System (Pre-CERCLIS) Screening Report. In 2011, the EPA completed a Preliminary Assessment. In August 2012, a search for potentially responsible parties (PRPs) was conducted. The PRP search identified historical sites that may have contributed to the PCE-contaminated groundwater plume. A Removal Assessment was initiated at the site in August 2012. Sample results from sub-slab soil gas and indoor air samples collected from nearby businesses and residential buildings determined PCE and TCE were present at concentrations that exceeded their respective Removal Action Levels and screening levels. Subsequently, a time-critical removal action memorandum was signed August 21, 2013.