The Tinkham Garage site covers 375 acres in Londonderry, New Hampshire. Improper disposal of oil, oily wastes, septic tank washings, and other hazardous substances occurred from 1978 through 1979. The site was added to the National Priorities List (NPL) on September 8, 1983. Cleanup is organized into two operable units (OUs), distinct problem areas addressed through separate remedial actions. Physical construction of the cleanup is complete, and the site has achieved ready-for-anticipated-reuse status, though it remains on the NPL and groundwater migration is not yet stabilized.
EPA has identified 26 contaminants of concern in soil and groundwater. These include chlorinated solvents such as trichloroethene, tetrachloroethene, and 1,1,1-trichloroethane, as well as benzene, polychlorinated biphenyls (PCBs), and various ketones and chlorinated methanes. In 2014 and 2016, elevated concentrations of 1,4-dioxane and PFAS (per- and polyfluoroalkyl substances) were detected in residential wells east of the site. Following federal limits set for PFAS in drinking water, 59 households have been offered bottled water and about 80 households are being monitored near the site.
Major cleanup actions included contaminated soil removal through vacuum extraction and excavation between 1994 and 1995, and groundwater pumping and treatment that ran until 2001. Drinking water wells at the Londonderry Green Apartment complex and several private wells were closed in 1983, and residents were connected to municipal water. On September 30, 2025, EPA issued an Interim Record of Decision for OU 02, selecting an extension of the existing municipal water line to connect homes impacted by site-related contaminants. A focused feasibility study was expected in spring 2025 to evaluate alternative water sources. A Record of Decision for OU 02 is scheduled for September 2026, with remedial action estimated for 2027. Human exposure to contamination is currently under control across the entire site, though groundwater migration is not yet stabilized. Institutional controls restricting certain land uses remain in place. Groundwater monitoring continues.
The site has been substantially redeveloped. Commercial businesses, including Home Depot, Staples, and restaurants, operate in the northeastern area. Residential communities, including condominiums and an active senior housing development with over 125 residences, occupy the northern and central areas. As of December 2024, seven on-site businesses employed 395 people and generated about $95.95 million in annual sales.
Community members can stay involved through EPA's Community Involvement Plan, finalized in September 2024. It explains the cleanup process, public participation opportunities, and key decision points where EPA considers public input. Site documents are available at Leach Library in Londonderry or at the EPA Region 1 Records and Information Center in Boston. Residents can contact Aaron Shaheen, the Community Involvement Coordinator, to be added to the mailing or email list, or to request a copy of the Interim Record of Decision. A sixth Five Year Review was completed in September 2024.
