Lewisite with sulfur mustard

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. 

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. 

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. 

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. 

Lewisite was produced and stockpiled by various nations, including Japan, the United States, and the Soviet Union. Lewisite saw use, too, in mixtures with sulfur mustard, where lewisite acted as a freezing-point depressant. The Japanese might have used lewisite in combat... 

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. 

Oily, colorless to brownish liquid with an odor like garlic. Mixture consists of 37 to 50% Sulfur mustard (C03-A001) and +63 to 50% Lewisite (C04-A002). The eutectic mixture is 37% Sulfur mustard and 63% lewisite. 

The world community has its own Scheduled chemical list with regard to agents of chemical warfare. Schedule I refers to those substances used exclusively for warfare such as the nerve gases, sulfur mustards, nitrogen mustards, and Lewisites. These are overtly banned. 

THIS CHAPTER contains a brief description of the methods used by toxicologists at Oak Ridge National Laboratory (ORNL) to derive the U.S. Army s interim reference doses (RfDs) for GA, GB, GD, VX, sulfur mustard, and lewisite. Those methods were based on the procedures outlined by the U.S. Enviromnental Protection Agency for Superfund risk assessment guidelines (EPA 1989) and for reference concentrations (EPA 1994). An alternative method, the benchmark-dose (BD) approach (Crump 1984) is also described. Because uncertainty factors are integral to both approaches, further consideration is also given to the statistical distribution and confidence associated with them. 

Minute quantities of sulfur mustard are used by various military and contract laboratories for defense research purposes, and for verification of Chemical Weapons Convention comphance. Bulk quantities of sulfur mustard are no longer manufactured in the USA. Military stockpiles of sulfur mustard are awaiting destruction or are in the process of being destroyed. Some sulfur mustard may also be found buried or abandoned at former defense sites. Sulfur mustard was frequently loaded into artillery shells and aerial bombs (often with lewisite). Various quantities of sulfur mustard also exist in other countries. Large amounts of sulfur mustard have been disposed of at sea. 

Little information is available regarding the toxieokineties of lewisite. Lewisite is readily absorbed by mueous membranes and, beeause of its lipophilicity, dermal absorption is signitieant (HSDB, 2004). Dermal absorption is reportedly more rapid than for sulfur mustard (Hurst and Smith, 2008). Axehod and Hamilton (1947) reported that radiolabeled ( " As) lewisite applied to a 0.4S em area of human skin was primarily fixed on the epidermis and that very little was found in the dermis most was detected in hair and hair follicles. In experiments with guinea pigs, histological examination revealed that lewisite applied to skin entered epidermis within 2 min and penetrated into the dermis within 10 min (Ferguson and Silver, 1947). Only trace amounts were detectable in the dermis at 24 h post-application. 

Sulfur mustard is a component of the H-series blister agents including undistilled sulfur mustard (H sulfur mustard with 20-30% impurities, also known as Levinstein mustard), distilled sulfur mustard (HD or HS 96% pure), a mustard-lewisite mixture (HL), and HD/agent T mixture (HT a mixture of HD and nonvolatile agent T), and an HD/agent Q mixture (HQ a mixture of HD and nonvolatile Agent Q (Agent Q is also known as sesquimustard). 

Management of Lewisite or Mustard-Lewisite exposure is similar to that of nitrogen and sulfur mustard exposures with two exceptions. First, patients exposed to Lewisite or the mixture will have an abrupt onset of symptoms and will likely present to emergency rooms immediately after exposure. On the other hand, because of the delayed effects, most patients with severe exposures to nitrogen or sulfur mustards will go home or elsewhere after their exposure and may only present later at emergency rooms or physicians offices when they begin developing symptoms. 

The second exception is that while an antidote is available for systemic effects of Lewisite exposure, there are no antidotes for nitrogen mustard or sulfur mustard toxicity, with one minor caveat if given within minutes after exposure, intravenous sodium thiosulfate may prevent death due to sulfur mustard exposure (25). Otherwise, the medical management for skin, ocular, and respiratory exposure is only supportive. One guideline physicians can follow is to keep skin, eye, and airway lesions free from infection. 

Liquids Some, but not all components of Sulfur/Arsenical Vesicants can be detected by M8 paper. All components of Sulfur/Arsenical Vesicants can be detected by M9 papers. The APD 2000 provides semi-quantitative identification of sulfur mustard/Lewisite mixtures. Colorimetric tubes are available which can detect thioethers, organic arsenic compounds as well as arsine (AsHg). Detection with PIDs or PIDs may be possible. Detection and identification with FT-IR is possible provided that the appropriate reference spectra are available. 

Unfortunately, vesicant exposure creates a huge problem because microscopic cellular damage occurs within very few minutes of exposure, but at a minimum, outward physical signs of that damage does not normally occur for at least 2 or 3 h after exposure, though usually longer. While phosgene oxime produces immediate pain on skin contact and Lewisite produces pain usually within 1 min after skin contact, sulfur mustard produces absolutely no pain on contact with the skin. As much as people do not like pain, pain is an extremely important protective mechanism for... 

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