Middlesex Sampling Plant (USDOE)

Overview

The Middlesex Sampling Plant is a 9.6-acre former atomic energy facility in Middlesex, New Jersey. It operated from 1943 to 1967, sampling, storing, testing, and transferring ores containing uranium, thorium, and beryllium. The site was added to the National Priorities List (NPL) in January 1999. The Department of Energy (DOE) took custody in 1980, and the U.S. Army Corps of Engineers (USACE) took over cleanup activities in 1997. The site is divided into two operable units (OUs): one for soil and one for groundwater.

Soil cleanup (OU 01) is complete. Workers removed about 35,000 cubic yards of contaminated soil from nearby properties and another 33,000 cubic yards from the Middlesex Municipal Landfill. Buildings were demolished and contaminated sediments removed in the mid-1990s. Soil contaminants included lead, radium-226, thorium-230, uranium isotopes, and several polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene. EPA declared soil cleanup administratively complete in September 2010 and says it poses no human health risks.

Groundwater cleanup (OU 02) is ongoing. The groundwater contains carbon tetrachloride, chloroform, and trichloroethylene (TCE), all exceeding New Jersey standards. Uranium isotopes are also present. Because residents and local industries rely on a public water supply rather than private wells, human exposure is currently considered under control. A Classification Exception Area and Well Restriction Area covering 240 private properties was established in November 2022 to restrict groundwater use. The selected cleanup approach includes monitored natural attenuation, in-situ chemical treatment, groundwater monitoring, and institutional controls. A pilot groundwater study began in 2023. Remedial design is expected to wrap up between December 2026 and February 2027, with active cleanup work set to begin between April and June 2027.

On April 1, 2024, the DOE transferred the property to the Borough of Middlesex. The borough plans to build Emergency Management and Department of Public Works facilities there. The DOE will continue to fund groundwater cleanup, carried out by the USACE, even as the land changes hands. The site has not yet been deleted from the NPL and construction is not yet complete.

Community members can find announcements about meetings and public comment periods in the Home News Tribune and the Star Ledger, as well as on EPA's regional Facebook page. For site-specific questions, residents can contact USACE Project Manager Kathleen Cuzzolino or reach out to EPA's Community Involvement Coordinator or Remedial Project Manager.