Organophosphorus agents (OPs) are pesticides (e.g. parathion, malathion, chlorpyrifos and dichlorvos); drugs and pro-drugs (e.g. echothiophate, métrifonate and cyclophosphamide); flame retardants and anti-wear agents [e.g. tricresyl phosphate (TCP)]; and chemical warfare nerve agents (CWNAs). CWNAs include G-agents: tabun, sarin, soman, cyclohexyl-sarin (cyclosarin); V-agents: VX, VR (RVX), CVX; and “Novichoks”: A-230, A-232, A-234.^1,2  OP pesticides and all other toxic OPs, excluding classical CWNAs, can be considered as “non-traditional nerve agents” (NTAs). NTAs are potential CWNAs and terrorist threat agents. Highly toxic OPs may result from cytochrome P₄₅₀ mediated metabolic oxidation of parent thiono-phosphoesters, e.g. paraoxon from parathion,³  or 2-(o-cresyl)-4H-1,3,2-benzodioxaphosphoran-2-one [CBDP; or cresyl-saligenin phosphate (CSP)] by cyclization of tri-ortho-cresyl phosphate (TOCP), a tri-cresyl phosphate (TCP) isomer.⁴  TCP is a flame retardant and anti-wear agent present in jet engine oils and hydraulic fluids. High temperature pyrolysis of jet fighter engine oils may also lead to toxic OPs such as trimethylolpropane phosphate (TMPP).⁵  Most OPs are potent irreversible inhibitors of cholinesterases (ChEs) and of many other serine hydrolases. However, TMPP is not an inhibitor of ChEs; it is a GABA antagonist, so toxic that it has been called “the poor man’s nerve agent”, and is also considered as a potential threat.⁶