4-1. General

a.    Blister agents (vesicants) are likely to be used to produce casualties and to force opposing troops to wear full protective equipment. Blister agents are used to degrade fighting efficiency rather than to kill, although exposure to such agents can be fatal. Thickened blister agents will contaminate terrain, ships, aircraft, vehicles, or equipment and present a persistent hazard. ; Vesicants include sulphur mustard (H and HD), nitrogen mustards (HN), lewisite (L) (this may be used in mixture with HD), and halogenated oximes (example, phosgene oxime (CX)). Halogenated oximes properties and effects are very different from those of the other vesicants.

b.    Vesicants burn and blister the skin or any other part of the body they contact. They may act on the eyes, mucous membranes, lungs, and skin; mustards may act on blood-forming organs. They damage the respiratory tract when inhaled and cause vomiting and diarrhea when ingested.

c.    Some vesicants have a faint odor; others are odorless. They often have more serious effects than is immediately apparent. Both L and CX cause immediate pain on contact. The mustards are insidious in action, with little or no pain at the time of exposure. In some cases, signs of injury may not appear for several hours.

d.   Vesicants poison food and water and make other supplies dangerous to handle.

e.    Vesicants can be disseminated by artillery shell, mortar shell, rocket, aircraft spray, and bomb.

f.    The severity of a blister agent burn is directly related to the concentration of the agent and the duration of contact with the skin.

4-2. Self-Aid

a.    Assume MOPP 4 whenever liquid or vaporized agents are known to be present. b.    Liquid vesicants in the eyes or on the skin require immediate decontamination procedures as outlined in appendix d.

4-3. Precautions in Receiving Casualties

a.    Casualties contaminated with vesicants endanger unprotected attendants. Individuals in contact with these casualties must be at MOPP 4, plus wear a butyl rubber apron.

b.    Special precautions must be taken in receiving contaminated casualties to prevent injury to others. Contaminated casualties are decontaminated outside the field MTF to prevent vapor accumulation indoors. They are kept separated from clean (uncontaminated) casualties until decontamination is completed. Contaminated litters, blankets, and equipment must be left outdoors. Decontamination is necessary for equipment, vehicles, watercraft, and aircraft that have been used to transport contaminated casualties. Appendix B contains further information on decontamination.

c.    Unhydrolyzed mustard on patients� skin surface can present a hazard to individuals receiving or treating these patients even after several hours. As mustard reacts with skin and subcutaneous tissue, it is hydrolyzed; however, the destroyed tissue becomes a barrier for complete hydrolyzation of excess mustard on the surface.

4-4. Protective Devices

a.    The protective mask protects only the face, eyes, and respiratory tract. The mask protects against both liquid and vapor forms of vesicants.

b.    Chemical protective overgarments help prevent the vesicant from reaching the skin.

4-5. Disposition of Casualties

See section V for disposition of casualties with blister agent burns.


4-6. Mustard (H and HD)

a.    Physical Properties. Mustard is an oily liquid ranging from colorless, when pure (neat), to dark brown when plant-run (unpurified form when first produced). Mustard is heavier than water, but small droplets float on water surfaces and present a special hazard in contaminated areas. It smells like garlic or horseradish. Distilled HD, the most common form of mustard, freezes at 57�F (14�C) and boils at 442�F (228�C). It is only slightly soluble in water, which gradually destroys it, but undissolved mustard may persist in water for long periods. It is most soluble in fats and oils. It is freely soluble in acetone, carbon tetrachloride, alcohol and liquid fuels (gasoline, kerosene, and diesel); however, these solvents do not destroy mustard. Mustard disappears from contaminated ground or materials through evaporation or through hydrolysis. It is rapidly destroyed by decontaminating chemicals or by boiling in water. The primary use of mustard is to cause delayed casualties by the liquid and vapor effects on the skin and the eyes and by the vapor effects through the respiratory system.

b.    Persistence. The persistence of hazard from mustard vapor or liquid depends on the degree of contamination by the liquid, type of mustard, nature of the terrain and soil, type of munition used, and weather conditions. Mustard may persist much longer in wooded areas than in the open. Mustard persists two to five times longer in winter than in summer. The hazard from the vapor is many times greater under hot conditions than under cool conditions. Standard chemical agent detector kits should be used to detect the presence of HD vapor in the field.

c.    Cumulative Effect. Even very small repeated exposures to mustard are cumulative in effect. For example, repeated exposures to vapors from spilled mustard can kill or produce 100 percent disability by irritating the lungs and causing a chronic cough and pain in the chest.

Figure 4-1. Casualty with mustard burn of the face and eyes.


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