Coakley Landfill is a 92-acre privately owned site straddling Greenland and North Hampton, New Hampshire. It accepted municipal and industrial waste from 1972 to 1982, then incinerator residue through 1985. EPA added it to the National Priorities List (NPL) in June 1986. The site is split into two operable units (OUs): OU 01 covers the 27-acre source area, and OU 02 covers offsite groundwater.
EPA identified more than 50 contaminants of concern at the site. Metals include arsenic, lead, chromium, cadmium, and beryllium. Organic chemicals include benzene, toluene, tetrachloroethene, chlorobenzene, vinyl chloride, and 1,4-dioxane. Polycyclic aromatic hydrocarbons (PAHs) are also present. Groundwater holds the largest share of contaminants, especially offsite, but soil, sediment, surface water, and solid waste are all affected. More recently, per- and polyfluoroalkyl substances (PFAS) have been found in groundwater and surface water, including Berrys Brook.
EPA's 1990 cleanup plan for the source area called for capping the landfill, collecting and venting landfill gases, and treating groundwater. That cap was completed in 1998, and most original contaminants have since dropped below cleanup levels. A 1994 decision for offsite groundwater selected monitored natural attenuation, institutional controls, and long-term monitoring. More than 20 private water supply wells are monitored semi-annually. Four exceed New Hampshire groundwater standards. Two have been fitted with treatment systems, and two have been connected to municipal water instead. A bedrock investigation completed between 2018 and 2021 assessed how contamination moves through deeper groundwater and whether private wells are at risk. The Coakley Landfill Group is now carrying out recommendations from that study and is evaluating how contaminated groundwater interacts with surface water.
The main health threat is potential use of contaminated groundwater as drinking water, along with incidental ingestion during contact with certain surface waters. EPA assessments say human exposure is currently under control, meaning no unacceptable pathways exist for people to come into contact with contaminants at this time. Physical construction across the site is complete, and land-use restrictions are in place. However, EPA has insufficient data to confirm whether groundwater contamination migration has stabilized. EPA has directed the Coakley Landfill Group to conduct an Engineering Evaluation and Cost Analysis to address the ongoing release of contaminants from the landfill to surface water, with a Non-Time Critical Removal Action to follow. Removal work for offsite groundwater is estimated to begin between February and April 2028. The site has not yet been deleted from the NPL, and the next five-year review is estimated between September and November 2026.
Community members can review site documents at the North Hampton Public Library, the Greenland Public Library, or the EPA Region 1 Records and Information Center in Boston. EPA released a community update fact sheet in October 2025. People who want hard copies or wish to be added to mailing or email lists can contact Community Involvement Coordinator Aaron Shaheen directly.
