b. Mass Casualty. A BW agent attack can produce a mass casualty situation at all levels of HSS. A major problem with a BW mass casualty situation is that HSS personnel are more susceptible to becoming a casualty to BW agents. Also, the ill patient may be the first indicator that a BW agent has been dispersed.
c. Decontamination. Decontamination is an individual and unit responsibility. However, some individuals may arrive at the MTF that have not been decontaminated or that become contaminated en route to the MTF. These individuals must be decontaminated at the MTF before they are admitted to prevent contamination of the MTF and exposure of medical personnel to the biological agent. See [Appendix G] for details on patient decontamination.
d. Treatment. Specific treatment is dependent upon the BW agent used. Patients are treated for symptomatic presentation unless the BW agent identity is known. Field Manuals 8-9 and 8-284 provide detailed information on medical management and treatment.
A-11. Effects of Chemical Weapons
a. A chemical agent is a chemical that is used to kill, seriously injure, or incapacitate man because of its physiological effects. They can be disseminated by artillery, aircraft, rocket, or by nonconventional means used by terrorists. When first employed in combat during World War I, the chemical weapon (chlorine) was so effective that the attacking Germans were not prepared to exploit the success.
b. Chemical agents are very effective weapons against poorly trained and equipped forces; however, they are less effective against well-trained forces.
A-12. Behavior of Chemical Weapons
Chemical agents can be disseminated as a gas, vapor, or aerosol under ambient conditions. They have a range of odors varying from none to highly pungent characteristics. Their stability is dependent upon the environmental conditions in the area of employment. See [Table A-11] for persistency of various chemical agents.
a. The toxicity of a chemical agent is not the same for everyone; each individual does not react exactly the same way to the same amount of an agent. Some are more resistant than others because of physiological factors. The dose is the quantity of a chemical received by the individual for percutaneous or oral doses and as a time-weighted concentration, milligrams-minute (m3), for inhalation. It is usually expressed as milligrams of agent per kilogram of subject body weight (mg/kg). The LD50 is the dose that kills 50 percent of the exposed population. The incapacitation dose 50 (ID50) is the incapacitation dose for 50 percent of the exposed subjects. The penetration of agents by various routes need not be accompanied by irritation or delayed superficial damage to the absorbent surface, but there are often unique signs and symptoms identifiable by the route of entry.
(1) Gaseous, vapor, and aerosol chemical agents often enter the body through the respiratory tract (inhalation injury). The agent may be absorbed by any part of the respiratory tract from the mucosa of the nose and mouth to the alveoli of the lungs. Aerosol particles larger than 5 μ tend to be retained in the upper respiratory tract; particles in the 1 to 5 μ range are retained in the deep volume of the lungs; while those below 1 μ tend to be breathed in and out again; although a few are retained in the deep volume of the lungs.