Nerve agents, sometimes also called nerve gases, are a class of organic chemicals that disrupt the mechanisms by which nerves transfer messages to organs. The disruption is caused by the blocking of acetylcholinesterase (AChE), an enzyme that catalyzes the breakdown of acetylcholine, a neurotransmitter. Nerve agents are acetylcholinesterase inhibitors used as poison.
Sarin is an extremely toxic synthetic organophosphorus compound. A colourless, odourless liquid, it is used as a chemical weapon due to its extreme potency as a nerve agent. Exposure is 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.
Tabun or GA is an extremely toxic synthetic organophosphorus compound. It is a clear, colorless, and tasteless liquid with a faint fruity odor. It is classified as a nerve agent because it fatally interferes with normal functioning of the mammalian nervous system. Its production is strictly controlled and stockpiling outlawed by the Chemical Weapons Convention of 1993. Tabun is the first of the G-series nerve agents along with GB (sarin), GD (soman) and GF (cyclosarin).
Soman is an extremely toxic chemical substance. It is a nerve agent, interfering with normal functioning of the mammalian nervous system by inhibiting the enzyme cholinesterase. It is an inhibitor of both acetylcholinesterase and butyrylcholinesterase. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations according to UN Resolution 687. Its production is strictly controlled, and stockpiling is outlawed by the Chemical Weapons Convention of 1993 where it is classified as a Schedule 1 substance. Soman was the third of the so-called G-series nerve agents to be discovered along with GA (tabun), GB (sarin), and GF (cyclosarin).
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell (cytotoxicity) or an organ such as the liver (hepatotoxicity). By extension, the word may be metaphorically used to describe toxic effects on larger and more complex groups, such as the family unit or society at large. Sometimes the word is more or less synonymous with poisoning in everyday usage.
VX is an extremely toxic synthetic chemical compound in the organophosphorus class, specifically, a thiophosphonate. In the class of nerve agents, it was developed for military use in chemical warfare after translation of earlier discoveries of organophosphate toxicity in pesticide research. In recent years, VX was found to be the agent used in the assassination of Kim Jong-nam. In its pure form, VX is an oily, relatively non-volatile, liquid that is amber-like in colour. Because of its low volatility, VX persists in environments where it is dispersed.
Acute toxicity describes the adverse effects of a substance that result either from a single exposure or from multiple exposures in a short period of time. To be described as acute toxicity, the adverse effects should occur within 14 days of the administration of the substance.
VG is a "V-series" nerve agent chemically similar to the better-known VX nerve agent. Tetram is the common Russian name for the substance. Amiton was the trade name for the substance when it was marketed as an insecticide by ICI in the mid-1950s.
Novichok is a group of nerve agents, some of which are binary chemical weapons. The agents were developed at the GosNIIOKhT state chemical research institute by the Soviet Union and Russia between 1971 and 1993. Some Novichok agents are solids at standard temperature and pressure, while others are liquids. It is thought that dispersal for the solids is possible by ultrafine powder.
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.
From 1948 to 1975, the U.S. Army Chemical Corps conducted classified human subject research at the Edgewood Arsenal facility in Maryland. The purpose was to evaluate the impact of low-dose chemical warfare agents on military personnel and to test protective clothing, pharmaceuticals, and vaccines. A small portion of these studies were directed at psychochemical warfare and grouped under the prosaic title of the "Medical Research Volunteer Program" (1956–1975). The MRVP was also driven by intelligence requirements and the need for new and more effective interrogation techniques.
VR is a "V-series" unitary nerve agent closely related to the better-known VX nerve agent. It became a prototype for the series of Novichok agents. According to chemical weapons expert Jonathan Tucker, the first binary formulation developed under the Soviet Foliant program was used to make Substance 33, differing from VX only in the alkyl substituents on its nitrogen and oxygen atoms. "This weapon was given the code name Novichok."
EA-3580 is a potent anticholinergic deliriant drug with a fairly long duration of action, related to the chemical warfare agent 3-Quinuclidinyl benzilate (QNB). It was developed under contract to Edgewood Arsenal during the 1960s as part of the US military chemical weapons program, during research to improve upon the properties of earlier agents such as QNB.
Demeton, sold as an amber oily liquid with a sulphur like odour under the name Systox™, is an organophosphate derivative causing irritability and shortness of breath to individuals repeatedly exposed. It was used as a phosphorothioate insecticide and acaricide and has the chemical formula C8H19O3PS2. Although it was previously used as an insecticide, it is now largely obsolete due to its relatively high toxicity to humans. Demeton consists of two components, demeton-S and demeton-O in a ratio of approximately 2:1 respectively. The chemical structure of demeton is closely related to military nerve agents such as VX and a derivative with one of the ethoxy groups replaced by methyl was investigated by both the US and Soviet chemical-weapons programs under the names V.sub.X and GD-7.
Throughout history, chemical weapons have been used as strategic weaponry to devastate the enemy in times of war. After the mass destruction created by WWI and WWII, chemical weapons have been considered to be inhumane by most nations, and governments and organizations have undertaken to locate and destroy existing chemical weapons. However, not all nations have been willing to cooperate with disclosing or demilitarizing their inventory of chemical weapons. Since the start of the worldwide efforts to destroy all existing chemical weapons, some nations and terrorist organizations have used and threatened the use of chemical weapons to leverage their position in conflict. A notable example includes the use of such weapons by the US government that sprayed more than 20 million gallons of various herbicides over Vietnam, Cambodia and Laos from 1961 to 1971. Agent Orange, which contained the deadly chemical dioxin, was the most commonly used herbicide. Other examples of the use of chemical weapons are Iraq’s Saddam Hussein on the Kurdish village Halabja in 1988 and their employment against civilian passengers of the Tokyo subway by Aum Shinrikyo in 1995. The efforts made by the United States and other chemical weapon destruction agencies intend to prevent such use, but this is a difficult and ongoing effort. Aside from the difficulties of cooperation and locating chemical weapons, the methods to destroy the weapons and to do this safely are also a challenge.
A-232 is an organophosphate nerve agent. It was developed in the Soviet Union under the FOLIANT program and is one of the group of compounds referred to as Novichok agents that were revealed by Vil Mirzayanov. A-232 is reportedly slightly less potent as a nerve agent compared to some of the other compounds in the series such as A-230 and A-234, having similar potency to the older nerve agent VR. However it proved to be the most versatile agent as it was chemically stable and remained a volatile liquid over a wide temperature range, making it able to be used in standard chemical munitions without requiring special delivery mechanisms to be developed.
A-234 is an organophosphate nerve agent. It was developed in the Soviet Union under the FOLIANT program and is one of the group of compounds referred to as Novichok agents that were revealed by Vil Mirzayanov. In March 2018 the Russian ambassador to the UK, Alexander Yakovenko, claimed to have been informed by British authorities that A-234 had been identified as the agent used in the poisoning of Sergei and Yulia Skripal. Vladimir Uglev, one of the inventors of the Novichok series of compounds, said he was "99 percent sure that it was A-234" in relation to the 2018 Amesbury poisonings, noting its unusually high persistence in the environment.
EA-3990 is a deadly carbamate nerve agent. It is lethal because it inhibits acetylcholinesterase. Inhibition causes an overly high accumulation of acetylcholine between the nerve and muscle cells. This paralyzes the muscles by preventing their relaxation. The paralyzed muscles include the muscles used for breathing.
EA-4056 is a deadly carbamate nerve agent. It is lethal because it inhibits acetylcholinesterase. Inhibition causes an overly high accumulation of acetylcholine between the nerve and muscle cells. This paralyzes the muscles by preventing their relaxation. The paralyzed muscles includes the muscles used for breathing.
A-230 is an organophosphate nerve agent. It was developed in the Soviet Union under the FOLIANT program and is one of the group of compounds referred to as Novichok agents that were revealed by Vil Mirzayanov. A-230 is possibly the most potent nerve agent for which specific toxicity figures have been published, with a human lethal dose estimated to be less than 0.1 mg. However it was felt to be less suitable for weaponisation than other agents such as A-232 and A-234, due to issues with the liquid agent exhibiting low volatility and solidifying at low temperatures, as well as poor stability in the presence of water.
