Medical Aspects of Chemical Warfare (2008) - The Black Vault

Cyanide Poisoningas “the cherry death”), and the Roman emperor Neroused cherry laurel water to poison members of hisfamily and others who displeased him. Dioscorides, aGreek physician who served in Nero’s army, compiledinformation on more than 600 species of plants withmedicinal value in the five books titled De MateriaMedica, recognizing the poisonous properties of bitteralmonds. Napoleon III proposed the use of cyanidesto enhance the effectiveness of his soldiers’ bayonetsduring the Franco–Prussian War; it has also been suggestedthat Napoleon died from cyanide. 3The first description of cyanide poisoning, by Wepferin 1679, dealt with the effects of extract of bitteralmond administration. 2 In 1731 Maddern demonstratedthat cherry laurel water given orally, into therectum, or by injection, rapidly killed dogs. 4 Althoughsubstances containing cyanide have been used for centuriesas poisons, cyanide was not identified until 1782,when Swedish pharmacist and chemist Carl WilhelmScheele 2 isolated cyanide by heating the dye PrussianBlue with dilute sulfuric acid, obtaining a flammablegas (hydrogen cyanide) that was water soluble andacidic. Scheele called this new acid Berlin blue acid,which later became known as prussic acid and todayis known as cyanide (from the Greek word “kyanos,”meaning “blue”). Scheele’s discovery may have costhim his life several years later, from either engagingin unsafe experimental practices such as taste testingand smelling HCN, or accidentally breaking a vial ofthe poison. A better understanding of the cyanideswas achieved in 1815 by the French chemist JosephLouis Gay-Lussac. 2 Gay-Lussac identified a colorless,poisonous gas called cyanogen, which had an almondlikeflavor and considerable thermal stability. Hiswork on acids, including HCN, led to the realizationthat acids do not need to contain oxygen, and that thecyanogen moiety could be shifted from compound tocompound without separating the individual carbonand nitrogen atoms.Terrorist and Military UsesAlthough ancient civilizations used plants containingcyanides to kill, it was not until World War I, inlate 1915 and early 1916, that cyanide was producedexpressly for the purpose of killing. France startedthe large-scale use of cyanide as a chemical weapon,producing approximately 8 million pounds of HCN bydistilling a concentrated solution of potassium cyanide(KCN) with dilute sulfuric acid. Even though HCNhad quick-kill properties and was not readily absorbedon charcoal (allowing penetration through enemy gasmasks), its use provided no tactical advantage. Thiswas due, in part, to small payload munitions and thehigh volatility of cyanide with no cumulative effects(cyanide is lighter than air, persisting for only a fewminutes in the open air). Concentrations sufficient toincapacitate or kill were not achieved. In addition,Germany learned of its use and equipped its troopswith masks capable of filtering out the gas.In September 1916, France tried another cyanidebasedpoison, cyanogen chloride, which is heavier andless volatile than HCN and had a cumulative effecton its victims. Cyanogen chloride was produced bychlorinating a saturated solution of KCN at 0°C (32°F).Its toxicity was similar to that of HCN, but cyanogenchloride was more effective at low concentrationsbecause it irritated the eyes and lungs. Cyanogenchloride also had a delayed toxic effect similar to lungirritants such as chlorine and phosgene. At the sametime that France launched cyanogen chloride, Austriaintroduced a poisonous gas derived from KCN andbromine. The resulting cyanogen bromide was stillhighly volatile, yet it had only a quarter of the volatilityof HCN and was less toxic. Cyanogen bromide had astrong irritating effect on the conjunctiva and the mucousmembranes of the respiratory system; however,because it corroded metals and was unstable in storage(gradually polymerizing into a toxicologically inertsubstance), the Austrians abandoned its use. 5During World War II, the Nazis employed HCNadsorbed onto a dispersible pharmaceutical base (ZyklonB) to exterminate millions of civilians and enemysoldiers in the death camps. Cyanide was detected inthe walls of crematoria almost 50 years later. 6,7 ZyklonB was also used as a fumigant and rodenticide torid ships of rodents by the United States and othercountries. Japan allegedly used cyanide against Chinabefore and during the war.In the late 1980s, reports indicated that cyanide-likeagents may have been used against the inhabitants ofthe Syrian city of Hama, 8 the Kurdish city of Halabja,Iraq, 9 and possibly Shahabad, Iran, during the Iran-IraqWar. 10 In addition to military operations, cyanide hasbeen used by individuals and terrorist organizations.One notorious incident was the poisoning of Tylenol(acetaminophen, manufactured by McNeill ConsumerProducts Co, Fort Washington, Pa) in the Chicago areain 1982, which killed seven people. 11 An acid and acyanide salt were found in several subway restroomsin Tokyo, Japan, in the weeks following the release ofnerve agents in the city in March 1995. 12Executions and SuicidesCyanide has been the typical agent used in “gaschambers,” in which a cyanide salt is dropped intoan acid to produce HCN. Gas chambers used in some373