Vesicant agents volatility

Standard burials are acceptable when contamination levels are low enough to allow bodies to be handled without wearing additional protective equipment. Cremation may be required if remains cannot be completely decontaminated. Although arsenic vesicant agents are destroyed at the operating temperature of a commercial crematorium (i.e., above 1000°F), the initial heating phase may volatilize some of the agents and allow vapors to escape. Additionally, combustion will produce toxic and potentially volatile arsenic oxides. 

Heat from a fire will increase the amount of agent vapor in the area. A significant amount of the agent could be volatilized and escape into the surrounding environment before it is consumed by the fire. Actions taken to extinguish the fire can also spread the agent. Combustion or hydrolysis of arsenic vesicants will produce volatile, toxic decomposition products (see Section 4.4.5). 

Mustard gas (H)—also known as yellow cross, yperite, sulfur mustard, Schwefellost, bis(2-chloroethyl) sulfide, and dichlor-diethylsulfide—is a chemical-warfare agent with both vesicant and systemic effects. H is colorless and almost odorless and is an oily liquid at 14-215°C with a molecular weight of 159.08. Except in extremely cold weather, the low vapor pressure (0.072 mm Hg at 20°C) and low volatility of H are sufficient to make contaminated surfaces a source of danger to anyone nearby. H is slightly soluble... 

Sulfur mustard can be very persistent in soil (Rosenblatt et al., 1995). Persistence depends on the soil type, pH, moisture content, and whether the agent is at the soil surface or buried. Small (1984) reported that when HD was applied to the soil surface, volatilization would be the main route of HD loss (half-life about 30 min), but if the soil was wet, hydrolysis would be the main loss pathway. When sprayed onto soil, a vesicant action was still apparent after about 2 weeks when the agent leaked into the soil, however, a vesicant action was still present after 3 years (DA, 1974). Rosenblatt et al. (1995) state that the persistence of sulfur mustard in soil is due to the formation of oligomeric degradation products that coat the surface of the mustard agent and that are resistant to hydrolysis. 

CWAs have been widely eondemned since they were first used on a massive scale during World War I. However, they are still stockpiled and used in many countries as they are cheap and relatively easy to produee, and can cause mass casualties. Although the blood agent CK is extremely volatile and undergoes rapid hydrolysis, the degradation of three types of vesicant CWAs, the sulfur mustards, nitrogen mustards, and Lewisite, results in persistent products. For... 

At ordinary temperatures (68 F.), its volatility is only 3.3 mg. i>er liter, which i.< low for a lung injurant but high for a vesicant. Dimethyl sulfate is very readily dccompo.scd by water so that its vapors quickly combine with moisture in the air to form sulfuric acid. ThU is one of the chief d( fect.s of this substance as a chemical agent. 

Little is known about lewisite s stability in the environment, but it can react with water in a manner whereby its volatility and most of its blistering potency are lost. As a potent blister agent, it has irritant effects on the eyes and respiratory system, and has similar toxicities to the other blister agents mentioned above (except that it exhibits less bone marrow suppression). Similar to its dichloroarsine cousins and phosgene oxime, but unlike the mustard vesicants, it can cause pain at the time of initial contact. There is often no erythema around the vesicles as with other mustard agents. 

Vesicants may be volatilized during a fire or be spread by efforts to extinguish the fire. Agents may be decomposed by heat to produce other toxic and/or corrosive gases. In addition. Sulfur/Arsenical Vesicants may react with steam or water during a fire to produce toxic and/or corrosive vapors. 

Sesqui-mustard, agent Q, QN2. Solid, Mp 56°C. volatility <1 mg/m3 at 20°C. British laboratory reported vesicant activity to be five times that of mustard gas and this may have been an underestimate. 

Agent T. Vesicant Mp 10°C. Like sesqui-mustard a low-volatility vesicant. Persistent. 

C. The chemical warfare agent lewisite (dichloro [2-chlorovinyl]arsine) is a volatile vesicant liquid that causes immediate severe irritation and necrosis to the eyes, skin, and ain/vays (see also p 372). 

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. 

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