Warfare Agents–Chemical
Chemical warfare has a long history that may have reached its zenith during World War I with the battlefield use of chlorine, phosgene, and mustard gases. More recently, Iraq used chemical agents in its war with Iran and against its own Kurdish population. In 1995, Aum Shinrikyo, a terrorist cult, released the nerve agent sarin in the Tokyo subway system during rush hour.
Chemical warfare agents are divided into groups largely on the basis of their mechanism of toxicity (Table II–59): nerve agents, vesicants or blister agents, blood agents or cyanides, choking agents, and incapacitating agents. Presenting symptoms and the clinical circumstances may help identify the agent and lead to effective treatment as well as proper decontamination.
Appearance | Vapor Pressure and Saturated Air Concentration (at 25°C) | Persistence in Soil | Toxic Doses (for 70-kg Man) | Comments (see text for additional clinical description) | |
|---|---|---|---|---|---|
Nerve agents (cholinesterase inhibitors; see text and Organophosphorus and Carbamate Insecticides) | |||||
Tabun (GA) | Colorless to brown liquid with fairly fruity odor | 0.07 mm Hg 610 mg/m3 Low volatility | 1–1.5 d | LC50 400 mg-min/m3 LD50 skin 1 g | Rapid onset; aging half-time 13–14 h. |
Sarin (GB) | Colorless, odorless liquid | 2.9 mm Hg 22,000 mg/m3 Highly volatile | 2–24 h | LC50 100 mg-min/m3 LD50 skin 1.7 g | Rapid onset; aging half-time 3–5 h. |
Soman (GD) | Colorless liquid with fruity or camphor odor | 0.4 mm Hg 3,060 mg/m3 Moderately volatile | Relatively persistent | LC50 50 mg-min/m3 LD50 skin 350 mg | Rapid onset; aging half-time 2–6 min. |
VX | Colorless to straw-colored odorless liquid | 0.0007 mm Hg 10.5 mg/m3 Very low volatility | 2–6 d | LC50 10 mg-min/m3 LD50 skin 10 mg | Rapid onset; aging half-time 48 h. |
Vesicants | |||||
Sulfur mustard (HD) | Pale yellow to dark brown liquid | 0.011 mm Hg 600 mg/m3 Low volatility | 2 wk–3 y | LC50 1500 mg-min/m3 LD50 100 mg/kg | Pain onset hours after exposure; fluid-filled blisters. |
Phosgene oxime (CX) | Colorless crystalline solid or liquid with intensely irritating odor | 11.2 mm Hg 1,800 mg/m3 Moderately volatile | 2 h | LC50 3200 mg-min/m3 LD50 unknown | Immediate pain, tissue damage within seconds; solid wheal formation. |
Lewisite (L) | Colorless to amber or brown oily liquid with geranium odor | 0.58 mm Hg 4,480 mg/m3 Volatile | Days | LC50 1200 mg-min/m3 LD50 40–50 mg/kg | Immediate pain, tissue damage in seconds to minutes; fluid-filled blisters. |
Riot control agents (lacrimators) | |||||
CS (chlorobenzylidene malonitrile) | White crystalline powder with pungent pepper odor | 0.00034 mm Hg 0.71 mg/m3 Very low volatility | Variable | LC50 60,000 mg-min/m3 Incapacitating dose: IC50 3–5 mg-min/m3 | Rapidly severe eye pain and blepharospasm; skin tingling or burning sensation; duration 30–60 min after removal from exposure. |
CN (mace, chloroacetophenone) | Solid or powder with fragrant apple blossom odor |
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