The Hercules, Inc. Gibbstown Plant is a 350-acre former chemical manufacturing site in Gibbstown, New Jersey. EPA added it to the Superfund National Priorities List in 1983 after discovering groundwater contamination. The site is divided into three operable units covering groundwater, soil and sediment, and a solid waste disposal area. Cleanup is active but not yet complete across all units.
Twenty-eight contaminants of concern have been identified at the site. These include volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, and cumene, along with heavy metals including lead, arsenic, mercury, nickel, chromium, silver, and zinc. Additional chemicals include phenol, diphenylamine, and dinitrotoluene compounds. Contamination is present in soil, sediment, groundwater, and surface water, including Clonmell Creek and an on-site stormwater basin.
A groundwater extraction and treatment system has run continuously to keep contaminated water from migrating off-site and to protect municipal drinking water wells downstream. The solid waste disposal area cleanup was completed in September 2014 and is now in routine operation and maintenance under state oversight. A final remedy for the groundwater and soil areas was selected in September 2018. It calls for excavating and biologically treating contaminated soil, chemically treating deeper soil, removing lead-contaminated soil off-site, and dredging sediment from the creek and stormwater basin. In 2020, EPA and New Jersey issued a consent decree requiring Hercules to carry out this work. Remedial design is currently underway, with a 30% design report expected by spring 2026 and remedial action estimated to begin between March and May 2027. A vapor intrusion study in 2011 found VOC levels in nearby homes within acceptable risk ranges, and no additional sampling was required. Human exposure and groundwater migration are both considered under control. EPA five-year reviews in 2015, 2020, and 2025 confirmed the site remains protective of human health and the environment.
Community members can stay involved through public meetings, notices, and fact sheet updates that EPA provides. Site documents, including decision records and review reports, are available at the EPA Region 2 Superfund Records Center at 290 Broadway, 18th Floor, New York, NY 10007-1866, and through EPA's Superfund website. Residents with questions can contact the EPA's Community Involvement Coordinator or the Remedial Project Manager.
