history of chemical warfare history of chemical warfare chemical weapons have been a part of warfare in most societies, although their use has been particularly controversial since the 20th century. part of a series onwar history prehistoric ancient post-classical early modern late modern industrial fourth-gen military organization command and control defense ministry army navy air force marines coast guard reserves ranks specialties: staff engineers intelligence reconnaissance medical military police land units: infantry armor cavalry artillery special forces signal corps naval units: warships submarines aircraft carriers landing craft auxiliary ship air units: fighters bombers command close air support electronic-warfare reconnaissance combat systems: fire-control system fire-control radar director (military) combat information center sonar radar historical: ship gun fire-control gun data computer torpedo data computer development: basic training military manoeuvrers combat training 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command of the sea full-spectrum dominance overmatch unrestricted warfare related outline of war just war theory principles of war philosophy of war war film military science fiction war game lanchester's laws security dilemma tripwire force mercenary war novel women in war war resister war studies anti-war movement horses in warfare wartime sexual violence lists battles military occupations military tactics operations sieges war crimes wars weapons writers ancient and medieval times ancient greek myths about heracles poisoning his arrows with the venom of the hydra monster are the earliest references to toxic weapons in western literature. homer's epics, the iliad and the odyssey, allude to poisoned arrows used by both sides in the legendary trojan war (bronze age greece). some of the earliest surviving references to toxic warfare appear in the indian epics ramayana and mahabharata. the "laws of manu," a hindu treatise on statecraft (c. 400 bc) forbids the use of poison and fire arrows, but advises poisoning food and water. kautilya's "arthashastra", a statecraft manual of the same era, contains hundreds of recipes for creating poison weapons, toxic smokes, and other chemical weapons. ancient greek historians recount that alexander the great encountered poison arrows and fire incendiaries in india at the indus basin in the 4th century bc. the art of war described the use of fire weapons against the enemy. arsenical smokes were known to the chinese as far back as c. 1000 bc and sun tzu's "art of war" (c. 200 bc) advises the use of fire weapons. in the second century bc, writings of the mohist sect in china describe the use of bellows to pump smoke from burning balls of toxic plants and vegetables into tunnels being dug by a besieging army. other chinese writings dating around the same period contain hundreds of recipes for the production of poisonous or irritating smokes for use in war along with numerous accounts of their use. these accounts describe an arsenic-containing "soul-hunting fog", and the use of finely divided lime dispersed into the air to suppress a peasant revolt in 178 ad. the earliest recorded use of gas warfare in the west dates back to the fifth century bc, during the peloponnesian war between athens and sparta. spartan forces besieging an athenian city placed a lighted mixture of wood, pitch, and sulfur under the walls hoping that the noxious smoke would incapacitate the athenians, so that they would not be able to resist the assault that followed. sparta was not alone in its use of unconventional tactics in ancient greece; solon of athens is said to have used hellebore roots to poison the water in an aqueduct leading from the river pleistos around 590 bc during the siege of kirrha. the earliest archaeological evidence of gas warfare is during the roman–persian wars. research carried out on the collapsed tunnels at dura-europos in syria suggests that during the siege of the town in the third century ad, the sassanians used bitumen and sulfur crystals to get it burning. when ignited, the materials gave off dense clouds of choking sulfur dioxide gases which killed 19 roman soldiers and a single sassanian, purported to be the fire-tender, in a matter of two minutes. quicklime (the old name for calcium oxide) may have been used in medieval naval warfare – up to the use of "lime-mortars" to throw it at the enemy ships. historian and philosopher david hume, in his history of england, recounts how in the reign of henry iii (r.1216 – 1272) the english navy destroyed an invading french fleet, by blinding the enemy fleet with quicklime. d’albiney employed a stratagem against them, which is said to have contributed to the victory: having gained the wind of the french, he came down upon them with violence; and gassing a great quantity of quicklime, which he purposely carried on board, he so blinded them, that they were disabled from defending themselves. in the late 15th century, spanish conquistadors encountered a rudimentary type of chemical warfare on the island of hispaniola. the taíno threw gourds filled with ashes and ground hot peppers at the spaniards to create a blinding smoke screen before launching their attack. the natives of the pernambuco province used pepper smoke during sieges; they would wait till the wind was blowing towards the enemy, and light a bonfire fillled with peppers. early modern era christoph bernhard von galen tried to use toxic fumes during the siege of the city of groningen in 1672. leonardo da vinci proposed the use of a powder of sulfide, arsenic and verdigris in the 15th century: throw poison in the form of powder upon galleys. chalk, fine sulfide of arsenic, and powdered verdegris may be thrown among enemy ships by means of small mangonels, and all those who, as they breathe, inhale the powder into their lungs will become asphyxiated. it is unknown whether this powder was ever actually used. in the 17th century during sieges, armies attempted to start fires by launching incendiary shells filled with sulfur, tallow, rosin, turpentine, saltpeter, and/or antimony. even when fires were not started, the resulting smoke and fumes provided a considerable distraction. although their primary function was never abandoned, a variety of fills for shells were developed to maximize the effects of the smoke. in 1672, during his siege of the city of groningen, christoph bernhard von galen, the bishop of münster, employed several different explosive and incendiary devices, some of which had a fill that included deadly nightshade, intended to produce toxic fumes. just three years later, august 27, 1675, the french and the holy roman empire concluded the strasbourg agreement, which included an article banning the use of "perfidious and odious" toxic devices. pirate captain thompson used "vast numbers of powder flasks, grenade shells, and stinkpots" to defeat two pirate-hunters sent by the governor of jamaica in 1721. the qing dynasty, used stinkpots specially in naval operations. those earthenware incendiary weapons were in part filled with sulphur, gunpowder, nails, and shot, while the other part was filled with noxious materials designed to emanate a highly unpleasant and suffocating smell to its enemies when ignited. stinkpots were used in the war of 1812 by the british navy during a bombardment of stonington, connecticut on august 9th, 1814. industrial era lyon playfair proposed the industrial manufacture of cyanide artillery shells for use during the crimean war. the modern notion of chemical warfare emerged from the mid-19th century, with the development of modern chemistry and associated industries. the first recorded modern proposal for the use of chemical warfare was made by lyon playfair, secretary of the science and art department, in 1854 during the crimean war. he proposed a cacodyl cyanide artillery shell for use against enemy ships as way to solve the stalemate during the siege of sevastopol. the proposal was backed by admiral thomas cochrane of the royal navy. it was considered by the prime minister, lord palmerston, but the british ordnance department rejected the proposal as "as bad a mode of warfare as poisoning the wells of the enemy." playfair's response was used to justify chemical warfare into the next century: there was no sense in this objection. it is considered a legitimate mode of warfare to fill shells with molten metal which scatters among the enemy, and produced the most frightful modes of death. why a poisonous vapor which would kill men without suffering is to be considered illegitimate warfare is incomprehensible. war is destruction, and the more destructive it can be made with the least suffering the sooner will be ended that barbarous method of protecting national rights. no doubt in time chemistry will be used to lessen the suffering of combatants, and even of criminals condemned to death. later, during the american civil war, new york school teacher john doughty proposed the offensive use of chlorine gas, delivered by filling a 10-inch (254 millimeter) artillery shell with two to three quarts (1.89–2.84 liters) of liquid chlorine, which could produce many cubic feet of chlorine gas. doughty's plan was apparently never acted on, as it was probably presented to brigadier general james wolfe ripley, chief of ordnance. in march 1868 during the war of triple aliance the paraguayan troops threw lit tubes full of asphixiating mixtures in their attempt to board brazilian ironclads with canoes. the attack failed since the tubes were easily put out by the defenders. a general concern over the use of poison gas manifested itself in 1899 at the hague conference with a proposal prohibiting shells filled with asphyxiating gas. the proposal was passed, despite a single dissenting vote from the united states. the american representative, navy captain alfred thayer mahan, justified voting against the measure on the grounds that "the inventiveness of americans should not be restricted in the development of new weapons." world war i gas casualties from the battle of estaires, april 10, 1918 a smelling case to allow officers to identify the gas by smell and thus act appropriately for protection and treatment the hague declaration of 1899 and the hague convention of 1907 prohibit the firing of any projectiles "the sole object of which is the diffusion of asphyxiating or deleterious gases." germany exploited this loophole by opening canisters filled with poison gas into the wind and letting it carry it towards the enemy lines, instead of launching it in artillery rounds. the french were the first to use chemical weapons during the first world war, using the tear gases ethyl bromoacetate and chloroacetone. they likely did not realize that effects might be more serious under wartime conditions than in riot control. it is also likely that their use of tear gas escalated to the use of poisonous gases. a canadian soldier with mustard gas burns, ca. 1917–1918 one of germany's earliest uses of chemical weapons occurred on october 27, 1914, when shells containing the irritant dianisidine chlorosulfonate were fired at british troops near neuve-chapelle, france. germany used another irritant, xylyl bromide, in artillery shells that were fired in january 1915 at the russians near bolimów, in present-day poland. the first full-scale deployment of deadly chemical warfare agents during world