Chemical weapons vesicants

Chemical warfare agents (CWA) are classified into several categories, for example, nerve agents and vesicants. Tear gases are forbidden as a method of warfare but still allowed for riot control purposes. The CWC fists chemicals in three Schedules, which have been constructed on the basis of the toxicity of the chemicals, their industrial use, and historical usage as warfare agents. Schedule 1 consists of families of toxic chemicals, which have been developed, produced, stockpiled, or used as chemical weapons, for example, sarin and mustard gas. These chemicals have little industrial use. Schedule 3, on the other hand, consists of 17 single chemicals with... 

Outside of military conflicts, exposure to sulfur mustard has occurred or may occur in work environments associated with chemical weapon materiel (e.g. storage depots, demilitarization facilities, research laboratories), during emergency response operations or remediation and decontamination activities, or during treaty verification activities in support of the Chemical Weapons Convention. Chemical weapons such as the vesicants are stiU considered potential military threats and terrorist targets. The most likely route of exposure to sulfur mustard is via aerosol/vapor exposure of the skin, eyes, and respiratory tract. 

Lewisite (2-chlorvinyldichlorarsin) is another vesicant agent. Unlike sulfur mustard, there has never been a documented use in armed conflict. It was first synthesized and described by the Belgian priest and chemist Julius Arthur Nieuwland (Nieuwland, 1904). During World War I, the US military chemist Winford Lee Lewis suggested and initiated its development into a chemical weapon, which due to the 1918 armistice in Europe was not used on the battlefield (Vilensky and Redman, 2003). 

Blister agents Also known as vesicants, these are chemical weapon compounds that cause severe blistering of the skin, as well as damage to the eyes, mucous membranes, respiratory tract and internal organs. This class of chemical weapon agent includes the arsenicals/Lewisites (L), phosgene oxime (CX), and sulfur mustards (HD, HN). 

Acute toxicity figures for man are not known but a lowest lethal concentration over 30 min of 6 ppm was quoted by Maynard (1989). The LD50 has been measured in a number of species (Table 3), while LCfsoS in a variety of species vary from 500 to 1500 mg min m 3 (Goldman and Dacre, 1989). The efficacy of lewisite, like that of mustard, depends partly upon its vesicant properties but lewisite is also a lethal systemic chemical weapon. About 30 drops (2.6 g), applied to the skin and not washed off or otherwise decontaminated would be expected to produce a fatal outcome in an average man. 

The most widespread and most open use of chemical weapons on a battlefield in recent decades was by Iraq in its conflict with Iran. This time the evidence of chemical use was conclusive. Undetonated shells were sampled and their contents were analyzed by several laboratories in Europe. A vesicant or blister agent (mustard) and a nerve agent (tabun) were identified. About 100 Iranian soldiers with chemical wounds were sent to European hospitals for care their wounds were consistent with vesicant (mustard) injury. A team appointed by the U.N. secretariat went to Iranian battlefields and hospitals and found chemical shells and patients with chemical injuries. The public outcry at the use of these weapons was less than overwhelming. Ignoring protests from the world community, Iraq continued to use these agents. 

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