Chemical Warfare (cont.)
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Mustard Gases as Chemical Weapons
Sulfur mustard has been used as a chemical weapon since World War I. Nitrogen mustard, a derivative of sulfur mustard, was one of the first chemotherapy agents but never has been used in warfare. These agents cause blistering of exposed surfaces. Both mustard agents rapidly penetrate cells and generate a highly toxic reaction that disrupts cell function and causes cell death. The chemical reaction is both temperature dependent and aided by the presence of water, which explains why warm, moist tissues are affected more severely. Actively reproducing cells, such as skin and blood cells, are most at risk.
Physical properties: Mustards are oily liquids with odors of mustard, onion, garlic, or horseradish. Highly soluble in oils, fats, and organic solvents, mustards quickly penetrate skin and most materials, including rubber and most textiles. Sulfur mustard is considered a persistent agent with low volatility at cool temperatures but becomes a major vapor hazard at high temperatures. Exposure to mustard vapor, not mustard liquid, is the primary medical concern. More than 80% of mustard casualties in World War I were caused by exposure to mustard vapor. Mustard vapor is 3 times more toxic than a similar concentration of cyanide gas; however, mustard liquid is also quite toxic. Skin exposure to as little as 1-1.5 teaspoons of liquid (7 g) is lethal to half of those exposed.
Mustards Signs, Symptoms, Diagnosis, and Decontamination
Mustards signs and symptoms
Mustards injure the skin, eyes, respiratory tract, GI tissues, and blood system. The pattern of toxicity depends partly on whether the person is exposed to liquid or vapor. Liquid exposure primarily damages the skin, producing an initial rash followed by blistering similar to a partial-thickness burn. Vapor exposure damages the upper respiratory tract (skin usually is not affected). Mustards penetrate cells in less than 2 minutes, yet signs and symptoms usually are delayed 4-6 hours (the range can be from 1-24 hours). The time it takes to show symptoms is shorter with high-concentration exposures, such as those occurring at increased room temperature and humidity.
Diagnosis of mustard exposure is based on what the doctor observes from the person’s signs and symptoms. No laboratory tests are useful.
Personal protective equipment: Liquid mustard contamination poses a risk for emergency care personnel. Ideally, they will be wearing appropriate personal protective gear.
Immediate decontamination within 2 minutes of exposure is the most important intervention for people who have skin exposure to mustard, because it rapidly becomes fixed to tissues, and its effects are irreversible. Even if an exposure takes place and a person shows no obvious sign and symptoms, decontamination is still urgent.
Medically Reviewed by a Doctor on 7/7/2016
Jeffrey L Arnold, MD, FACEP
Suzanne White, MD
Francisco Talavera, PharmD, PhD
Raymond J Roberge, MD, MPH, FAAEM, FACMT
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