Mustard mixed with Lewisite

There has been no verified use of Lewisite on a battlefield, although Japan may have used it against China between 1937 and 1944 (Trammel, 1992). Lewisite is probably in the chemical warfare stockpile of several countries. Lewisite is sometimes mixed with mustard to lower the freezing point of mustard Russia has this mixture (Madsen, Major, Medical Corps, U.S. Army, 1995, personal communication). 

Agent vapors of both series cause eye irritation. However, there is no significant difference in the concentration that will irritate the eyes and the one that will produce eye injury. Although impacts from exposure to vesicants occur almost at once, contact with vapors or the liquid agent neither irritates the skin nor produces visible dermal injuries until after a substantial latency period. In contrast, HL (C03-A010), sulfur mustard mixed with lewisite, produces immediate pain due to the arsenic mustard component. 

Lewisite (C04-A002) has been mixed with sulfur mustard (C03-A001) to prevent the sulfur mustard from freezing in the shell as well as to enhance its toxicity. 

Mixes distilled mustard (HD) combined with lewisite (L) and distilled mustard (HD) combined with bis (2-chloroethyl sulfide) monoxide (T)... 

Phenyldichlorarsine, ethyldichloroarsine, and methyl-dichloroarsine have similar properties and toxicities as lewisite. They may be mixed with sulfur mustard similarly as can be done with lewisite and mustard mixtures, and this can confuse the diagnosis between either an arsenical or a mustard injury. 

CW agents may also be encountered as mixtures or solutions of one agent in another, or of an agent in a solvent. The mixing of lewisite with sulphur mustard has been undertaken to lower the vapour pressure and freezing point of the mustard and hence to increase its persistence, without reducing the effective CW payload of weapon systems. Sulphur mustard has also been mixed with phenyldichlorarsine, the mixture being referred to as Winterlost, i.e. winter mustard. 

As lewisite is a liquid it may be disseminated by shells, bombs or rockets or sprayed from aircraft. Lewisite can be mixed with sulphur mustard, which depresses the freezing point and renders sulphur mustard usable over a wider range of temperatures than sulphur mustard itself. 

Formulation is also used to manipulate the fate of the agent. Soman, VX, Lewisite, and sulfur mustard can be mixed with high-molecular-weight thickeners to increase droplet size and thereby decrease primary vaporization. Such additives are generally used to promote efficient agent deposition on the target site. Thickeners can also increase agent persistence and may hamper decontamination efforts. 

The freezing temperature for mustard is 57°F. This high freezing point makes mustard unsuitable for delivery by aircraft spraying or for winter dispersal. Therefore, to lower the freezing point, mustard must be mixed with another substance. During World War I, mustard was mixed with chloropicrin, chlorobenzene, or carbon tetrachloride to lower its freezing point.1 Today, mustard can be mixed with Lewisite to increase its volatility in colder weather. 

Fishermen periodically recover chemical weapons and are burned through accidental exposure to sulphur mustard. This is because when sulphur mustard comes in contact with cold water a tarry substance forms around the exterior while the interior remains viscous over a period of many decades. The exterior consists mainly of precipitates derived from thickening agents (Fishermen then break open the crusty exteriors as they haul their catches into their boats and may then become exposed or contaminate their vessels as a result). The chemical composition of the tarry exterior is not well understood partly because it varies from case to case. Various polymer materials, such as alloprene and poly [methyl methacrylate] (PMMA), for example, were sometimes combined with sulphur mustard to lower its freezing temperature. Solvents such as chlorobenzene, have also been combined with sulphur mustard. Finally, sulphur mustard was often mixed with arsenic-containing agents, such as lewisite and diphenychloroarsine. 

The freezing point of sulfur mustard has been reduced in a number of ways to prevent the agent from solidifying in weapons in cold weather. In WWI, mustard was mixed with various solvents, e.g. carbon tetrachloride and benzene. In WWII, Britain produced it from thiodiglycol and hydrogen chloride as a 6 4 mixture with the oligomer T (Scheme 1.1), also known as O mustard. T has somewhat greater vesicant activity than sulfur mustard, is less volatile and more persistent. Other nations mixed mustard with lewisite, which also accelerated the onset of effects and increased the vapour hazard. 

Lewisite, CHCl=CHAsCl2, 2-chlorovinyldichloroarsine, named after its discoverer W. L. Lewis, was produced by the USA and shipped to Europe in 1918, too late to be used in WWI. Between the wars it was also produced by Japan and the Soviet Union. It is relatively easily made from arsenic trichloride and acetylene, although the process is technically more difficult than the production of sulfur mustard. Lewisite is more volatile (bp 190 °C) than sulfur mustard and hence it is less persistent it also appears to be more sensitive to environmental moisture. In contrast to sulfur mustard, its initial effect (skin pain or irritation) is almost instant, and blisters appear within a few hours. There has been no confirmed instance of use, although Japan is suspected of having used lewisite in China in WWII. In addition to being stockpiled as a neat agent, lewisite was mixed with sulfur mustard to speed up the onset of action and to depress the freezing point of the latter. 

Incineration is furthermore applicable to destruction of mixtures of an arsenical agent with another compound, such as another agent, or a polymer added as thickener. In particular, the vesicant Lewisite has sometimes been mixed with yperite or mustard . 

Lewisite may be mixed with other agents, such as mustard gas (HL), which may delay its clinical effects. Caustic agents also cause bums with tissue oedema and fluid loss but the formation of blisters is unusual. 

One such decontaminant is supertropical bleach (STB). STB is a mixture of chlorinated lime and calcium oxide containing about 30% available chlorine. It can be used either as a dry mix or as a slurry to decontaminate some equipment surfaces and terrain. The dry mix is prepared with two parts bleach to three parts earth by volume. A slurry typically consists of 40 parts STB to 60 parts by weight of water. This material is then sprayed or swabbed on the contaminated surface (see Bleaching agents). STB is an effective decontaminant for mustard, lewisite, and VX. It is less effective against nerve agents other than VX. 

IR spectrum of triple mixture containing 1,2-dichloroethane as an additive apart from mustard gas and lewisite is presented on Fig.5. Judging from the fact that the bands at 1378 and 1010 cm 1 have relatively low intensity the sample contains lower quantity of mixed type of mustard gas in a comparison with usual one (absorption in the range of 1440-1400 cm"1 and at the band of about 1200 cm1). a-Lewisite shows up the strong bands at 933 and 1554 cm1. The last one has undoubtedly asymmetric form as it was for mustard gas-lewisite mixture what indicates the presence of P-lewisite in the sample. 

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