Nonpersistent nerve agents

The nerve agents (GA, GB, and VX) are usually odorless, colorless, and tasteless. GA and GB are nonpersistent nerve agents which primarily present a vapor hazard. The vapors from these agents would present the primary casualty producer since they can be carried downwind quickly. Under most releases and meteorological conditions GA and GB produce the greatest downwind hazard distance. Thermal decomposition of GA and GB begins at approximately 130°C (266°F) and they completely decompose in 2.5 hours at 150°C (302°F). 

Nerve agents are absorbed both through the skin and via respiration. Because VX is an oily, nonvolatile liquid it is well absorbed through the skin (persistent nerve agent), although it can also be absorbed by inhalation. Thus, VX is more of a percutaneous threat than by inhalation, whereas the G agents (nonpersistent), which are also liquids, pose more of an inhalation hazard because of their vapor pressure. Sarin (GB) is the most volatile, but evaporates less readily than water, while cyclosarin (GF) is the least volatile of the G agents. 

Chemical/Pharmacetical/Other Class Soman is a human-made nonpersistent anticholinesterase compound or organophosphate (OP) nerve agent, irreversible cholinesterase inhibitor, and chemical warfare agent. It is a light liquid with a camphorlike odor. 

Binary Nerve Agents may be either nonpersistent or persistent. Evaporation rates, decomposition rates, and permeation rates in porous material of the crude Nerve Agents may be different from the standard "G" series, "V" series, or "GV" series agents because of the presence of unreacted components and reaction byproducts. 

One band on munitions manufactured prior to 1960 indicates a munition with a nonpersistent toxic agent (nerve, blood, or choking) filling. 

All munitions, both persistent and nonpersistent toxic agent fillings of all categories (nerve, blister, blood, and choking), manufactured after 1976 have only one band. 

Three bands indicate a munition manufactured between 1960 and 1976 with a nerve agent filling (both persistent and nonpersistent). 

Mask-Only Command Only the protective mask is worn. The mask-only command is given in these situations 1. When riot control agents are being employed and no chemical or biological threat exists. 2. In a downwind vapor hazard of a nonpersistent chemical agent. The mask-only command is not appropriate when blister agents or persistent nerve agents are present. 

Had gas warfare started early in World War II, phosgene would probably have been used widely by the Allied and the Axis armies wherever the tactical situation called for the employment of a nonpersistent, delayed-action agent. Sometime in 1S>42 or thereafter, evidence indicates that as a stockpile accumulated the Germans would have introduced tabun, and phosgene would then have had to share the field with the new nerve gas. 

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