Twin Cities Air Force Reserve Base (Small Arms Range Landfill)

Overview

The Small Arms Range Landfill sits on about 2 acres near the Minnesota River and Minneapolis-St. Paul International Airport. It operated from 1963 to 1972, accepting general base refuse and industrial waste such as painting sludge, paint filters, and sludge from leaded aviation gasoline. The U.S. Air Force owns the property and is responsible for cleanup. The site was added to the National Priorities List (NPL) in July 1987 and removed in December 1996 after cleanup eliminated health threats.

Contamination was found in groundwater, soil, and surface water. Twenty-eight contaminants of concern were identified, including volatile organic compounds such as benzene, toluene, and trichloroethene. Heavy metals include arsenic, cadmium, chromium, lead, mercury, nickel, selenium, silver, and zinc. Other substances found include beryllium, copper, vanadium, dibutyl phthalate, and 2-butanone. Arsenic, beryllium, cadmium, lead, nickel, selenium, and vanadium were detected at levels exceeding Safe Drinking Water Act standards. About 64,700 people in the area rely on public and private wells for drinking water.

The cleanup remedy, selected in March 1992, relies on monitored natural attenuation. That means natural processes reduce contamination over time rather than active removal. The remedy also includes site maintenance, access restrictions, and ongoing groundwater and surface water monitoring. Groundwater migration is stable and contained in its original area. Human exposure is currently under control across the entire site, with no unacceptable exposure pathways identified. Zoning restrictions prevent incompatible uses like residential development and must stay in place for the cleanup to remain protective.

Five-year reviews check that conditions remain safe even after cleanup is complete. Reviews were completed in 1998, 2003, 2008, 2013, 2018, and most recently in April 2023. The 2023 review confirmed the remedy is protective of human health and the environment in the short term, as long as institutional controls are maintained. The next review is expected between April and June 2028. The Air Force is also planning to sample for per- and polyfluoroalkyl substances (PFAS) starting around 2025, following PFAS detections at the nearby Air Force Reserve base.

Community members with questions can contact EPA Remedial Project Manager Nicole Goers by phone or email. Documents are available through the Twin Cities Air Force Small Arms Landfill Key Documents collection, and the Air Force maintains the Administrative Record for the site.