EPA Superfund Site

LONGHORN ARMY AMMUNITION PLANT

TX | EPA ID TX6213820529

About this site’s exposure pathways: As of August 2025, the Longhorn Army Ammunition Superfund site is considered “Insufficient Data to make a Human Exposure evaluation” (HEID) because of a newly identified exposure pathway and/or contaminant(s) known as per-fluor-alkyl substances (PFAS) in the soil and groundwater. The site was previously categorized as Human Exposure Under Control (HEUC), and the limited data available, based on a preliminary site investigation and review of PFAS releases at the site in 2023, found PFAS in groundwater in several wells above the current maximum concentration levels (MCLs) and above the regional screening levels in the soil. The concentrations in soil, ground water, and surface water need to be delineated and assessed for potential exposure risks to ensure there is no risk to human populations and the current remedies implemented at the site.

EPA uses this HEID 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. Planned activities to collect sufficient information to evaluate this new potential exposure are to conduct a remedial investigation (RI), which will include a Human Health Risk Assessment (HHRA) and information about the human interactions with potentially contaminated media. The PFAS contaminants may be co-mingled with legacy contaminants in groundwater associated with other contaminant releases. One or more new operable units (OUs) may be established to facilitate response actions. Direct soil exposure and ingestion of ground water pathways must be evaluated. EPA anticipates a human exposure evaluation by 2027.