The Cinnaminson Township (Block 702) Ground Water Contamination site covers about 400 acres in Cinnaminson and Delran townships in Burlington County, New Jersey. Groundwater contamination was discovered in the early 1980s when regulators reviewed monitoring data tied to landfill closures. The site has been listed on the National Priorities List, which guides EPA decisions about which sites need federal cleanup attention. Today, 29 businesses operate on-site, supporting 500 jobs and roughly $159 million in annual sales.
EPA has identified 47 contaminants of concern. The main problem is groundwater contaminated with volatile organic compounds (VOCs), a group of chemicals that vaporize easily at room temperature. Specific contaminants include trichloroethene, tetrachloroethene, vinyl chloride, 1,2-dichloroethane, benzene, chloroform, and arsenic. These appear in groundwater, soil, and soil vapor across the site. Some contaminants have also spread into off-site groundwater areas. A baseline health risk assessment found that drinking water exposure to these VOCs and arsenic posed significant risks to nearby residents.
Cleanup is organized into four operable units, or OUs. OU1 addresses on-site groundwater using a pump-and-treat system. That system ran from 2000 to 2013, then EPA ran a two-year shutdown test to check whether continued pumping was still needed. The test ended in 2015 and EPA is evaluating the results. OU2 covers the landfill cap. A 2014 decision found the existing clay cap was sufficient and no further action is needed there. OU3 targets contaminated soil and groundwater at industrial facilities on the northwestern part of the site. Source area removal finished in July 2022, and design for additional work is expected to wrap up between December 2027 and February 2028, with construction to follow through mid-2028. OU4 addresses off-site groundwater contamination, with a remedy selected in June 2021 that calls for pumping, treating, and either discharging or reinjecting the cleaned water. An ongoing vapor intrusion investigation has found trichloroethylene and perchloroethylene in soil gas and indoor air at homes near industrial areas. Vapor mitigation systems have been installed at several residences to cut exposure through this pathway.
According to EPA performance measures, human exposure at the site is currently under control. However, groundwater migration is not yet under control, meaning contaminated groundwater is still moving. Physical construction is not complete. The most recent five-year review, completed in May 2024, confirmed that protective measures remain in place. Institutional controls, including zoning restrictions and a well restriction area, limit land use and prevent new wells from drawing contaminated water.
Community members can review site documents at the EPA Superfund Records Center in New York or at the Cinnaminson Public Library at 1619 Riverton Road, Cinnaminson, NJ, reachable at (856) 829-9340. For direct questions, contact the EPA's Community Involvement Coordinator or Remedial Project Manager.
