20thcentury adverseeffects asphyxiatingandpoisonous biological chemicalwarfare chemicalweapons chemicalweaponsdisposal gases gaspoisoning his027010med039000sci034000his027100pol035010his036060 history humanrights incineration lewisite(poisongas) medical military poisons politicalfreedom politicalscience qv663i59v1993 qv666 science security testing toxicity toxicology unitedstates veterans worldwarii