EPA Superfund Site

MOUNTAIN PINE PRESSURE TREATING

AR | EPA ID ARD049658628

About this site’s exposure pathways: As of September 2025, the Mountain Pine Pressure Treating Superfund site is considered “Insufficient Data to make a Human Exposure evaluation” (HEID) because of a newly identified exposure pathway and/or contaminant(s). Arsenic was reevaluated under EPA Integrated Risk Information System (IRIS) in 2025, resulting in updates to both the oral reference dose and the cancer slope factor. These updates lower the applicable arsenic screening levels for a composite worker exposure scenario in surficial soil to below the cleanup levels outlined in the ROD. The site was previously categorized as “Current Human Exposures Under Control” (HEUC). The remedy removed and treated soil with arsenic concentrations greater than the cleanup goal, which was protective of industrial workers. There is no current activity in the area where contamination was left in place, but future activity could occur.

EPA uses this Human Exposure status when there is a lack of evidence to suggest that actual or reasonably anticipated human exposures are occurring and that those exposures are above acceptable risk-based levels. The planned activities to collect sufficient information to evaluate this new exposure pathway and/or contaminants(s) are to do a thorough evaluation of the existing soil data from the Remedial Investigation (RI) and Remedial Action (RA). The existing data will be used to perform a Human Health Risk Assessment (HHRA) to see if an unacceptable risk exists. If there is insufficient data available from the RI and RA to perform a HHRA, then additional sampling will be conducted to fill data gaps. EPA currently anticipates that there will be sufficient data to make a Human Exposure evaluation by July 2027. This will provide sufficient time to evaluate existing data and collect additional data (if necessary) and to perform the HHRA.