Aberdeen Proving Ground

Aberdeen Proving Ground is a U.S. Army installation located in Harford County, Maryland, along the upper Chesapeake Bay. Established in 1917, it is one of the Army's oldest active proving grounds and has long served as a center for the testing and evaluation of weapons, ordnance and military equipment. The installation includes two principal areas: the Aberdeen Area, used primarily for ordnance testing, and the 13,000-acre Edgewood Area, where the Army has conducted chemical research programs, manufactured chemical agents, and tested, stored and disposed of toxic materials since 1917. Edgewood Arsenal, formally designated in 1918, included plants that manufactured mustard agent, chloropicrin and phosgene, along with facilities for filling artillery shells with these chemicals.

There are concerns about potential carcinogenic health hazards at Aberdeen Proving Ground due to exposure to a range of environmental contaminants documented in soil, sediment, groundwater and surface water:

1. TCE (trichloroethylene): TCE is an industrial solvent widely used for degreasing metal parts. In 1991, TCE contamination was discovered in Harford County's Perryman well field near the installation, and a 1996 cleanup decision for the Nike Site required extraction and treatment of TCE-contaminated groundwater. Exposure to TCE has been associated with several cancers, including kidney cancer and non-Hodgkin lymphoma.
2. Other volatile organic compounds: Sampling near the Michaelsville Landfill in the Aberdeen Area detected solvents and related VOCs including vinyl chloride, methylene chloride, acetone and benzene. Some of these compounds, particularly vinyl chloride and benzene, are recognized carcinogens, and concerns remain about potential past exposures.
3. Heavy metals: Mercury, lead and chromium have been detected at the installation, and pesticides containing thallium, selenium and antimony were reportedly disposed of in the unlined Michaelsville Landfill. Long-term exposure to certain heavy metals may potentially be linked to cancer and other chronic health effects.
4. PCBs: Polychlorinated biphenyls, once common in transformer oils, were reportedly disposed of in the Michaelsville Landfill and have been detected in environmental samples. PCBs are classified as probable human carcinogens.
5. Chemical warfare agent degradation products: Decades of manufacturing, testing and disposal of chemical agents in the Edgewood Area left breakdown products of these agents in soil and groundwater, along with unexploded ordnance and disposed materials such as napalm and white phosphorus. The potential health implications of historical exposure to these substances remain a subject of concern and study.

Aberdeen Proving Ground includes two EPA National Priorities List sites under the Superfund program. The Michaelsville Landfill site was listed in October 1989, and the Edgewood Area was listed in 1990. The Army leads the cleanup with EPA oversight, and dozens of cleanup decisions have been completed across the installation's operable units. In the most recent five-year review process, completed between 2023 and 2025, the review concluded that remedies were protective at 32 of 33 operable units, while recommending additional actions at 11 of them. Land use controls remain in place to restrict incompatible uses such as residential development.

It is important to note that while there are documented contaminants and concerns about potential exposure at Aberdeen Proving Ground, establishing a definitive link between service at the installation and any individual's illness can be complex. Research into the long-term health effects of these exposures is ongoing. Veterans and civilian workers who spent time at Aberdeen Proving Ground may wish to stay informed about cleanup developments, document their service history, and consult the Department of Veterans Affairs about health evaluations and potential benefits.