New explosive compounds that are less sensitive to shock and high temperatures are being tested as replacements for TNT (2,4,6-trinitrotoluene) and RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine). Two of these explosives, DNAN (2,4-dinitroanisole) and NTO (3-nitro-1,2,4-triazol-5-one), have good detonation characteristics and are the main ingredients in a suite of insensitive munitions (IM) explosives. Both compounds, however, are more soluble than either TNT or RDX. Data on their fate could help determine if DNAN and NTO have the potential to reach groundwater and be transported off base, an outcome that could create future contamination problems on military training ranges and trigger regulatory action. In this chapter, we describe how quickly IM constituents (DNAN, NTO, nitroguanidine, RDX and ammonium perchlorate) dissolve from three IM formulations (IMX-101, IMX-104 and PAX-21) and how solutions of IM compounds interact with different types of soils. This information, coupled with the mass of IM formulations scattered on a range, will allow estimates of the dissolved IM mass loads, their subsequent transport and fate, and their likelihood of reaching groundwater.