GTA performed a Phase I Environmental Site Assessment (ESA) of a wooded 300-acre parcel proposed for single-family residential development. A prior Phase I ESA performed by another firm indicated a small pile of roofing shingles that might contain asbestos and no other significant environmental concerns at the site. GTA personnel performed a site reconnaissance, interviews with knowledgeable parties, and a records search at local historical societies and the National Archives in College Park, Maryland. GTA determined that, during World War II, the site contained a large munitions plant. It is believed that the M69 incendiary bomb, which is filled with napalm (i.e., jellied gasoline), was the primary ordnance manufactured at the site. Recognized environmental conditions (RECs) associated with the former munitions plant include, but are not limited to, unexploded ordnance (UXO); ordnance and explosive waste (OEW); gasoline and chemical storage areas; incendiary bomb filling areas; maintenance areas; and a bomb testing area devoid of vegetation.
GTA retained Explosive Ordnance Technologies, Inc. (EOTI) to perform a preliminary geophysical survey and subsurface exploration to evaluate specific portions of the site for the presence of UXO and other buried metallic objects using magnetic (MAG) and electromagnetic (EM) geophysical survey techniques. EOTI observed two M69 canisters on the ground surface, and metal parts/fragments associated with M69 munitions were observed on the ground surface and below grade.
GTA performed surface soil sampling, and installed temporary well points, to evaluate soil and groundwater quality on portions of the site. Several heavy metals, including antimony, copper, and lead, were detected above the applicable soil cleanup criteria. Potential cleanup cost liability, including identification and removal of surface and buried explosive waste, was estimated at greater than $2M.