Nitro-aromatic and heterocyclic compounds such as 2,4,6-trinitrotoluene (TNT), l,3,5-trinitro-l,3,5-triazacyclohexane (RDX), 1,3,5,7-tetranitro-l,3,5,7-tetrazacyclooctane (HMX), have been identified worldwide in soil and groundwater, at sites related to military activities. Among these chemicals, the toxicology of TNT is better known; however, gaps of knowledge still exist. We characterized the soil ecotoxicology of these energetic polynitro substances and their degradation products. The toxicities of these chemicals on microbial, plants, and invertebrate (oligochaete) species, and to cultured mammalian cell systems were examined using spiked and field soil samples. A sensitivity distribution ranking the responses of species was assembled for establishing soil benchmarks for explosives such as TNT. Preliminary field studies were also carried out using earthworm mesocosms. These approaches will increase the toxicological understanding of energetic compounds and our ability to detect exposure/toxicities of these substances in the field, and aid in establishing environmentally acceptable criteria, which are of great interest to land managers.