Loring Air Force Base

Overview

Loring Air Force Base is a roughly 9,000-acre former military installation in Limestone, Maine. It operated from 1953 until closing in 1994. The EPA added it to the National Priorities List in 1990 after finding widespread contamination from aircraft maintenance, fuel handling, weapons operations, and on-site landfills. The base is divided into 15 operable units, each targeting a specific area or type of contamination.

Contaminants include volatile organic compounds (VOCs) such as trichloroethene, tetrachloroethene, benzene, and vinyl chloride in groundwater. Metals including lead, cadmium, chromium, arsenic, and mercury appear in soil, sediment, and surface water. Pesticides like DDT, chlordane, and heptachlor are present in sediments. Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) have been found in soils and sediments. The State of Maine restricts fish consumption from Greenlaw Brook, Chapman Pit, and the Little Madawaska River and its tributaries. The U.S. Air Force is also investigating per- and polyfluoroalkyl substances (PFAS), including PFOS and PFOA, after confirming their presence in groundwater, surface water, soil, sediment, and fish tissue from areas where firefighting foams were historically used. A report on PFAS risk to human health is expected by late 2026.

The Air Force is the responsible party and has completed all cleanup design and construction work across the site. Major actions included removing over 1,000 cubic yards of low-level radioactive waste, capping two landfills totaling 27 acres, excavating and treating contaminated soil and sediment, and establishing five groundwater management zones with institutional controls. Bioremediation pilot studies are underway to treat residual VOC contamination in bedrock groundwater. A 2013 review found soil no longer poses unacceptable risk for residential use, so land use controls for soil were lifted. Institutional controls remain in place for groundwater and cleanup components. In 1998, about 3,900 acres were transferred to the U.S. Fish and Wildlife Service for the Aroostook National Wildlife Refuge. The rest became the Loring Commerce Center, an industrial and business park.

Human exposure is currently under control and construction is complete across most units. Groundwater migration is not yet stabilized. A combined remedial investigation and feasibility study for basewide groundwater is estimated for completion between September and November 2028. The most recent five-year review was completed in September 2025. The site has not yet been deleted from the National Priorities List.

Community members with questions about land use restrictions or cleanup status can contact the EPA's Community Involvement Coordinator or the Remedial Project Manager. State-level questions can be directed to the Maine Department of Environmental Protection.