Ken don't limit yourself to just looking for AO or Agent Orange. Try herbicide Orange(HO), 2,4-D and 2,4,5-T, picloram, cacodylic acid, herbicides, pesticides(herbicides are a pesticide) vegetation control, and most of all dioxin(2,3,7,8TCDD). Also you can try contamination like TPH's, PAH's, SVOC's, VOC's.(Pesticides can be in a number of these chemical catergories)You also might want to look at EPA(superfund), ATSDR, Chemical Corps, GAO. Any agency or outside contractor who may have done testing of the soil or drinking water.