Pease Air Force Base

Overview

The former Pease Air Force Base sits on 4,365 acres in Portsmouth and Newington, New Hampshire. It closed in 1991 after decades of military aircraft operations that left behind contamination in soil, groundwater, surface water, and sediment. The site was added to the National Priorities List in February 1990 and has been divided into 14 operable units to address different areas and contamination types. Most remedial construction work is complete, and the site achieved sitewide ready for anticipated reuse status in July 2007.

Contaminants include volatile organic compounds such as trichloroethene, tetrachloroethene, benzene, and toluene in groundwater. Chlorinated compounds, heavy metals like lead, arsenic, and chromium, polycyclic aromatic hydrocarbons, pesticides including DDT and chlordane, and phthalates are found across soil, sediment, and groundwater. PFAS, per- and polyfluoroalkyl substances from historical firefighting activities, have contaminated both public and private drinking water wells and are a current focus of cleanup efforts.

The U.S. Air Force is the responsible party for cleanup. Early actions removed contaminated drums and soil, installed groundwater extraction and treatment systems, capped landfills, and excavated contaminated sediments. Two groundwater treatment systems are now operating and have treated over 900 million gallons, reducing PFAS concentrations below New Hampshire and EPA drinking water limits. The Air Force also funded a treatment system for three City of Portsmouth drinking water wells at the Pease Tradeport. A full remedial investigation into PFAS extent on and off the former base is underway, with a report scheduled by mid-2026. EPA assessments show human exposure is currently under control, though groundwater migration status remains uncertain because EPA cannot yet confirm whether contaminated groundwater movement has stabilized.

Much of the former base has been redeveloped. Land was transferred for a public airport, the New Hampshire Air National Guard, highway expansion, and the Great Bay National Wildlife Refuge. The Pease International Tradeport, completed in 2000, now hosts over 270 businesses, education facilities, and government offices. Institutional controls including zoning restrictions remain in place to prevent land uses that could expose people to remaining contamination or damage cleanup systems.

Community members can get involved through the Restoration Advisory Board, which meets quarterly and gives residents a chance to ask questions and provide input on cleanup decisions. Routine water quality monitoring continues for all Portsmouth supply wells on or near Pease, as well as private drinking water wells off the Tradeport. Records are available at the Pease AFB Site Information Repository at 20 Short Street in Portsmouth, or at the EPA Region 1 Records and Information Center in Boston. Additional information is at www.epa.gov/superfund/pease. For questions, contact EPA's Community Involvement Coordinator Aaron Shaheen or Remedial Project Manager Mike Daly.