1-4

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1-4. LUNG-DAMAGING (CHOKING) AGENTS

Lung-damaging (choking) agents attack lung tissue and cause irritation of the respiratory system. Damage can also result in secondary infection.

a. Types of Choking Agents. Lung-damaging agents include phosgene (CG), diphosgene (DP), chlorine (Cl), and chloropicrin (PS). Phosgene is the lung-damaging agent most likely to be used.

b. Methods of Dissemination. Lung-damaging agents can be delivered by artillery shell, mortar shell, rocket, aircraft bomb or bomblet, or missile. Lung-damaging agents are usually disseminated as gasses. Phosgene can be in liquid form when the temperature is below 46oF (7.8oC).

c. Characteristics of Lung-Damaging Agents. Phosgene is colorless both as a gas and as a liquid. Phosgene has an odor that resembles the smell of newly mowed hay, grass, or green corn. Chlorine has a characteristic odor and produces immediate irritation of the respiratory system. Lung-damaging agents are classified as nonpersistent.

d. Absorption of Lung-Damaging Agents. Lung-damaging agents are absorbed through the respiratory system. If the casualty has been exposed to a lethal concentration of CG, death usually results within 24 to 48 hours. Exposure to very high concentrations of CG can result in death within 5 hours.

e. Physiological Effects. Phosgene attacks the lungs by damaging the alveoli (air sacs) and capillaries and by scarring the lungs. Damage to lung tissue can cause blood plasma to seep into the lungs and result in pulmonary edema. This condition, sometimes called "dry land drowning," interferes with the exchange of oxygen and waste products between the air in the lungs and the red blood cells of the circulatory system. The trachea, bronchi, and other parts of the respiratory tract are irritated, but not significantly damaged.

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