The Michaelsville Landfill sits within Aberdeen Proving Ground, a 17,000-acre military testing facility in Aberdeen, Maryland. The 20-acre landfill accepted mixed waste from roughly 1970 to 1980 without a liner. It was added to the EPA's Superfund National Priorities List in October 1989. The site is divided into 16 operable units covering different areas and contamination types, and cleanup work is still active across many of them.
Contaminants found in soil, groundwater, surface water, sediment, and soil gas include heavy metals such as lead, mercury, arsenic, and cadmium. Volatile organic compounds including benzene, trichloroethene, and vinyl chloride are present in groundwater and soil gas. The site also contains pesticides like DDT and dieldrin, polychlorinated biphenyls (PCBs), explosive residues including TNT and RDX, and unexploded ordnance. Per- and polyfluoroalkyl substances (PFAS), linked to historic use of aqueous film-forming foam for firefighting, have been identified as well. A multistage PFAS remedial investigation covering several site areas began in 2025.
The U.S. Army is the lead cleanup agency. EPA provides oversight, and the Maryland Department of the Environment also participates. The Army and EPA signed a Federal Facilities Agreement in March 1990 to guide investigations and remedies. EPA has issued Records of Decision for 12 of the 16 operable units. Cleanup methods across the units include landfill capping, landfill gas collection, excavation, soil stabilization, monitored natural attenuation, and vapor intrusion controls. The most recent five-year review was completed on July 22, 2024. Physical construction of cleanup is complete, though groundwater migration status cannot yet be determined due to data uncertainty, and not all cleanup goals for current and future land uses have been achieved sitewide. Final remedial action is estimated to begin between September and November 2028.
EPA assessments indicate that human exposure is currently under control across the entire site. Land use controls restrict residential development, daycares, schools, and playgrounds in affected areas, and prevent access to contaminated groundwater and sediments. The Army posts signs and conducts patrols to discourage trespassing.
Community members can attend the Aberdeen Proving Ground Restoration Advisory Board meetings, held quarterly on the fourth Thursday of January, March, July, and October from 7:00 to 9:00 p.m. Meetings use a hybrid format, with in-person attendance at the Ramada Inn, 1700 Van Bibber Road, Edgewood, MD. Announcements are posted on the U.S. Army Garrison APG Facebook page. Site records are available at Harford County Public Library branches in Edgewood and Aberdeen, and at Washington College's Clifton M. Miller Library in Chestertown. Records are also accessible at Building E6882 at Aberdeen Proving Ground by appointment.
