East Basin Road Groundwater

Overview

The East Basin Road Groundwater site sits within a roughly 5,000-acre area near New Castle County Airport in New Castle, Delaware. It includes the New Castle Air National Guard Base and associated Army facilities. EPA added the site to the National Priorities List (NPL) in March 2023, making it eligible for federal Superfund cleanup funding. The site is also known by several other names, including New Castle Public Wells Ground Water Plume and Delaware Air National Guard Facility.

The main contaminants are per- and polyfluoroalkyl substances (PFAS), specifically perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), along with volatile organic compounds (VOCs). These have been detected in groundwater that feeds 11 public drinking water wells serving approximately 209,000 people. PFAS are man-made chemicals used since the 1950s in products like nonstick cookware, firefighting foams, and stain-resistant fabrics. They do not break down in the environment and can accumulate in people and animals over time. Two water providers, Artesian Water Company and the City of New Castle's Municipal Services Commission, currently operate treatment systems that bring PFAS levels below Delaware's proposed drinking water standards. Treated water meets all current federal and state standards.

EPA and the Delaware Department of Natural Resources and Environmental Control (DNREC) completed a preliminary assessment, site inspection, and expanded site inspection. A combined remedial investigation and feasibility study began on February 1, 2024. A surface water and sediment investigation is planned to start in mid-June 2026. No cleanup remedy has been selected yet, and no construction has begun. EPA currently lacks enough data to draw conclusions about whether human exposures are fully controlled or whether groundwater contamination is stabilized.

EPA developed a Community Involvement Plan based on interviews with residents and stakeholders. In August 2023, EPA held both an in-person and virtual public meeting in New Castle to explain the Superfund process. Community members were offered the option of forming a Community Advisory Group. A 60-day public comment period took place when the site was proposed to the NPL in September 2022, and most comments supported the listing. Public documents related to the site are available at the New Castle Public Library, the Route 9 Library and Innovation Center, and the EPA Region III office in Philadelphia. An appointment is needed before visiting any of those locations.

Community members can contact EPA's Community Involvement Coordinators or the Remedial Project Manager directly for questions. Spanish-language assistance is also available. DNREC's Environmental Scientist Stephanie Gordon serves as the state-level point of contact.