The history of chemical warfare dates from antiquity. Chemical weapons have been a part of warfare in most societies for centuries. However, their usage has been extremely controversial since the 20th century.
Chemical warfare is recorded in the ancient periods of Greece, Rome, Carthage, India, China, and South Africa. Soldiers poisoned arrows, water supplies, or dispersed toxic smokes.
Chemical weapons were first used on a large scale by most major powers in World War I, employing the gases mustard, phosgene, and chlorine, and others, causing lung scarring, blindness, and death. During World War II, Nazi Germany used a commercial hydrogen cyanide blood agent named Zyklon B to commit industrialised genocide against Jews and other populations in gas chambers.Longerich, Peter (2010). Holocaust: The Nazi Persecution and Murder of the Jews. Oxford; New York: Oxford University Press. . The Holocaust resulted in the largest death toll due to chemical weapons in history.From Cooperation to Complicity: Degussa in the Third Reich, Peter Hayes, 2004, pp 2, 272, The Empire of Japan also used chemical warfare in China during the Second Sino-Japanese War, including mustard gas and lewisite.
Nazi Germany discovered nerve agents during the war, but did not use them for fear of Allied retaliation. In the Cold War, many countries stockpiled chemical weapons. The Soviet and United States chemical weapons programs became the first and second largest in world history, focusing on sarin, VX/VR, and mustard, primarily for battlefield use in Europe. The use of chemical weapons in the Iran–Iraq War and in the Syrian civil war saw thousands killed by nerve agents and blister agents.
At the end of the Cold War, the 1993 Chemical Weapons Convention sought a legally binding, worldwide ban on the production, stockpiling, and use of chemical weapons and their precursors. Large-scale stockpile destruction efforts followed, with the US eliminating its arsenal by 2023. the treaty has 193 state parties; Syria and Russia are widely believed to have violated its prohibitions on stockpiling and use while Israel and North Korea remain non-parties. Small research quantities are treaty-permitted as part of CBRN defense.
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 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 Sasanians 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 may have been used in medieval naval warfare, including to use of "lime-mortars" to throw it at enemy ships. Scottish historian David Hume, in his work The History of England, recounted how during the reign of Henry III of England the English navy destroyed an invading French fleet by attacking it with quicklime.David Hume, History of England, Volume II.
China Chinese writings from 1000 BCE contain 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." Literary sources of Chinese history mention that in 559 BCE the predynastic Qin state poisoned the Jing River, poisoning men and horses and forcing the retreat of other warring states such as the Jin and Lu. 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. Chinese writings also describe the use of finely divided lime dispersed into the air to suppress a peasant revolt in 178 AD.
Various Chinese sources from eleventh to seventeenth centuries describe mixtures of "poison gunpowder" suitable for creating grenades or trebuchet-launched bombs. This has included arsenic and crotonaldehyde, and is described in the Huolongjing and Tiangong Kaiwu.
Americas In the late 15th century, Spanish conquistadors encountered chemical warfare on the island of Hispaniola when Taíno threw gourds filled with ashes and ground hot peppers at the Spaniards to create a blinding smoke screen before launching their attack.
The people of Pernambuco province used pepper smoke during sieges; they would wait till the wind was blowing towards the enemy, and light a bonfire filled with peppers.
Early modern era
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 belladonna, 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 1719.
The Qing dynasty used stinkpots in naval operations.Needham, Joseph (1986). Science and Civilization in China: Volume 5, Chemistry and Chemical Technology, Part 7, Military Technology: the gunpowder epic. Taipei: Caves Books Ltd. Pages 189. 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. During the War of 1812, the Royal Navy used stinkpots in a bombardment of Stonington, Connecticut on 9 August 1814.Johnson, Rossiter. Chapter XVI. Operations Along the Coast. A History of the War of 1812–1815 between the United States and Great Britain. Rossiter Johnson.
Industrial era
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 (1.892.84 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 Alliance, 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.
In June 1898, during the Spanish–American War, Spanish inventors Manuel Daza and Antonio Meulener tested the tóxpiro or tóspiro, a chemical artillery grenade of unknown composition. They fired it from the battleship Pelayo against a barge loaded with eight farm animals, killing all of them without damaging the barge. Despite this, the Spanish government was not interested.
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
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.