Hopkins Farm, also known as the Thiokol Corp Site, sits in Plumstead Township, Ocean County, New Jersey. Chemical wastes disposed of there during the late 1950s and early 1960s contaminated both soil and groundwater. The site was added to the EPA's National Priorities List in 1984, which flags sites needing federal cleanup attention, and has since been fully cleaned up and removed from that list.
Eighteen contaminants were identified across soil and groundwater. Groundwater contained acetone, benzene, chlorobenzene, chloroform, chromium, lead, manganese, mercury, tetrachloroethene, toluene, trichloroethene, and zinc. Soil contained bis(2-chloroethoxy) methane, bis(2-chloroethyl)ether, bis(2-ethylhexyl)phthalate, cadmium, and selenium. Some of those soil contaminants were also found in groundwater.
The New Jersey Department of Environmental Protection investigated the site from 1987 to 1991. Between 1992 and 1994, about 1,441 tons of contaminated soil were excavated and removed. A risk assessment found that no further soil cleanup was needed. EPA issued a Record of Decision in 1996 calling for no further action on soil, along with long-term groundwater monitoring and institutional controls. Institutional controls are legal or administrative tools that limit how land or groundwater can be used, keeping people away from any remaining contamination.
By 2001, groundwater monitoring showed only iron and aluminum above federal and state standards. EPA concluded that exposure to those metals would not cause adverse health effects, and New Jersey agreed. The site was deleted from the National Priorities List in August 2002. Human exposure is under control, and contaminated groundwater migration is stabilized. The site is considered sitewide ready for anticipated use, meaning all cleanup goals have been met and no unacceptable risks remain. Monitoring of groundwater, surface water, and sediments continues to confirm the site stays safe.
Community members with questions can contact the EPA's Community Involvement Coordinator.
