ethyl methylphosphonothiolate, VX 1, were investigated with five oxidizingagents. In all the cases, the formation of the VX N-oxide 7 was observed prior to the subsequent oxidation and hydrolysis into the nontoxic O-ethyl methylphosphonate 2. Magnesium monoperoxyphthalate (MMPP) is probably one of the most active reagents to achieve the complete detoxification of VX 1. The decontamination using MMPP