Mustard gas or sulfur mustard are names commonly used for the organosulfur chemical compound bis(2-chloroethyl) sulfide, which has the chemical structure S(CH2CH2Cl)2, as well as other species. In the wider sense, compounds with the substituents −SCH2CH2X or −N(CH2CH2X)2 are known as sulfur mustards or nitrogen mustards, respectively, where X = Cl or Br. Such compounds are potent alkylating agents, which can interfere with several biological processes. Also known as mustard agents, this family of compounds comprises infamous cytotoxins and blister agents with a long history of use as chemical weapons. The name mustard gas is technically incorrect; the substances, when dispersed, are often not gases but a fine mist of liquid droplets. Sulfur mustards are viscous liquids at room temperature and have an odor resembling mustard plants, garlic, or horseradish, hence the name. When pure, they are colorless, but when used in impure forms, such as in warfare, they are usually yellow-brown. Mustard gases form blisters on exposed skin and in the lungs, often resulting in prolonged illness ending in death.
Phosgene is an organic chemical compound with the formula COCl2. It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. It can be thought of chemically as the double acyl chloride analog of carbonic acid, or structurally as formaldehyde with the hydrogen atoms replaced by chlorine atoms. Phosgene is a valued and important industrial building block, especially for the production of precursors of polyurethanes and polycarbonate plastics.
Chemical warfare (CW) involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from nuclear warfare, biological warfare and radiological warfare, which together make up CBRN, the military acronym for chemical, biological, radiological, and nuclear, all of which are considered "weapons of mass destruction" (WMDs), a term that contrasts with conventional weapons.
Sarin is an extremely toxic organophosphorus compound. A colourless, odourless liquid, it is used as a chemical weapon due to its extreme potency as a nerve agent. Exposure can be lethal even at very low concentrations, where death can occur within one to ten minutes after direct inhalation of a lethal dose, due to suffocation from respiratory paralysis, unless antidotes are quickly administered. People who absorb a non-lethal dose and do not receive immediate medical treatment may suffer permanent neurological damage.
The use of toxic chemicals as weapons dates back thousands of years, but the first large-scale use of chemical weapons was during World War I. They were primarily used to demoralize, injure, and kill entrenched defenders, against whom the indiscriminate and generally very slow-moving or static nature of gas clouds would be most effective. The types of weapons employed ranged from disabling chemicals, such as tear gas, to lethal agents like phosgene, chlorine, and mustard gas. These chemical weapons caused medical problems. This chemical warfare was a major component of the first global war and first total war of the 20th century. The killing capacity of gas was profound, with about 90,000 fatalities from a total of 1.3 million casualties caused by gas attacks. Gas was unlike most other weapons of the period because it was possible to develop countermeasures, such as gas masks. In the later stages of the war, as the use of gas increased, its overall effectiveness diminished. The widespread use of these agents of chemical warfare, and wartime advances in the composition of high explosives, gave rise to an occasionally expressed view of World War I as "the chemist's war" and also the era where weapons of mass destruction were created.
Diphosgene is an organic chemical compound with the formula ClCO2CCl3. This colorless liquid is a valuable reagent in the synthesis of organic compounds. Diphosgene is related to phosgene and has comparable toxicity, but is more conveniently handled because it is a liquid, whereas phosgene is a gas.
The United Kingdom possesses, or has possessed, a variety of weapons of mass destruction, including nuclear, biological, and chemical weapons. The United Kingdom is one of the five official nuclear weapon states under the Treaty on the Non-Proliferation of Nuclear Weapons. The UK renounced the use of chemical and biological weapons in 1956 and subsequently destroyed its general stocks.
Chloropicrin, also known as PS and nitrochloroform, is a chemical compound currently used as a broad-spectrum antimicrobial, fungicide, herbicide, insecticide, and nematicide. It was used as a poison gas in World War I and the Russian Invasion of Ukraine. Its chemical structural formula is Cl3C−NO2.
Phosgene oxime, or CX, is an organic compound with the formula Cl2C=N−OH. It is a potent chemical weapon, specifically a nettle agent. The compound itself is a colorless solid, but impure samples are often yellowish liquids. It has a strong, disagreeable and irritating odor. It is used as a reagent in organic chemistry.
Chemical, biological (CB) — and sometimes radiological — warfare agents were assigned what is termed a military symbol by the U.S. military until the American chemical and biological weapons programs were terminated. Military symbols applied to the CB agent fill, and not to the entire weapon. A chemical or biological weapon designation would be, for example, "Aero-14/B", which could be filled with GB, VX, TGB, or with a biological modification kit – OU, NU, UL, etc. A CB weapon is an integrated device of (1) agent, (2) dissemination means, and (3) delivery system.
Disulfur decafluoride is a chemical compound with the formula S2F10. It was discovered in 1934 by Denbigh and Whytlaw-Gray. Each sulfur atom of the S2F10 molecule is octahedral, and surrounded by five fluorine atoms and one sulfur atom. The two sulfur atoms are connected by a single bond. In the S2F10 molecule, the oxidation state of each sulfur atoms is +5, but their valency is 6. S2F10 is highly toxic, with toxicity four times that of phosgene.
Green Cross (Grünkreuz) is a World War I chemical warfare pulmonary agent consisting of chloropicrin, phosgene and/or trichloromethyl chloroformate.
The Hypo helmet, or British Smoke Hood, was an early British World War I gas mask, designed by Cluny Macpherson.
Chemical weapons were widely used by the United Kingdom in World War I. The use of poison gas was suggested by Winston Churchill and others in Mesopotamia during the interwar period, and also considered in World War II, although it appears that they were not actually used in these conflicts. While the UK was a signatory of the Hague Conventions of 1899 and 1907 which outlawed the use of poison gas shells, the conventions omitted mention of deployment from cylinders.
Acute inhalation injury may result from frequent and widespread use of household cleaning agents and industrial gases. The airways and lungs receive continuous first-pass exposure to non-toxic and irritant or toxic gases via inhalation. Irritant gases are those that, on inhalation, dissolve in the water of the respiratory tract mucosa and provoke an inflammatory response, usually from the release of acidic or alkaline radicals. Smoke, chlorine, phosgene, sulfur dioxide, hydrogen chloride, hydrogen sulfide, nitrogen dioxide, ozone, and ammonia are common irritants.
The German phosgene attack of 19 December 1915 was the first use of phosgene gas against British troops by the German army. The gas attack took place at Wieltje, north-east of Ypres in Belgian Flanders on the Western Front in the First World War. German gas attacks on Allied troops had begun on 22 April 1915, during the Second Battle of Ypres using chlorine against French and Canadian units. The surprise led to the capture of much of the Ypres Salient, after which the effectiveness of gas as a weapon diminished, because the French and British introduced anti-gas measures and protective helmets. The German Nernst-Duisberg-Commission investigated the feasibility of adding the much more lethal phosgene to chlorine. Mixed chlorine and phosgene gas was used at the end of May 1915 against French troops and on Russian troops on the Eastern Front.
Chlorine gas poisoning is an illness resulting from the effects of exposure to chlorine beyond the threshold limit value.
Chemical weapons have been a part of warfare in most societies for centuries. However, their usage has been extremely controversial since the 20th century.
The Small Box Respirator (SBC) was a British gas mask of the First World War and a successor to the Large Box Respirator. In late 1916, the respirator was introduced by the British with the aim to provide reliable protection against chlorine and phosgene gases. The respirator offered a first line of defence against these. The use of mustard gas, was begun by the Germans; a vesicant ("blister agent") that burnt the skin of individuals that were exposed to it. Death rates were high with exposure to both the mixed phosgene, chlorine and mustard gas, however with soldiers having readily available access to the small box respirator, death rates had lowered significantly. Light and reasonably fitting, the respirator was a key piece of equipment to protect soldiers on the battlefield.
