Lesson 1/Learning Event 4
LEARNING EVENT 4:
DISCUSS CONCEPTS OF CHEMICAL OPERATIONS
In a contaminated environment, success of combat or support operations will depend in part upon an
understanding of chemical agents and their effect. Chemical agents can be classified as persistent or
non-persistent, according to their duration of effectiveness after release. They can also be classified as
nerve, blister, choking or blood agents, according to their physiological action on the body. Nerve
agents are both persistent and non-persistent types. Blister agents are usually persistent. The choking
and blood agents are non-persistent.
An attack with weapons that release liquid or droplets is likely to involve the use of persistent agents.
An attack with weapons that release a vapor or gas is likely to involve the use of non-persistent agents.
Chemical Agents and Chemical Agent Effects
The types of chemical agents, their symbols, and their characteristics are discussed in the following
paragraphs. US agents of the particular type are listed in figure 1 on page 19.
Nerve Agents: affect the nervous system of man. They are highly toxic in both vapor and liquid form.
They are very quick-acting when inhaled. They act more slowly when absorbed through the skin. The
casualties caused by nerve agents may range from mild disability to death depending on the dose
received and the adequacy and speed of first aid. In a survey situation, V agents will be of more concern
than G agents because V agents are more persistent.
Blister Agents: affect the eyes and lungs and blister the skin. They are effective in small quantities.
They are quickly absorbed through the skin. Signs of injury often do not appear for several hours.
Blister agents lewisite and phosgene oxime, however, cause immediate pain and irritation. Blister
agents are usually persistent and are of great concern in chemical surveys.
Blood Agents: affect the ability of body cells to absorb oxygen. They cause symptoms ranging from
convulsions to coma. They enter the body by being inhaled. A person who receives a high dose may
become unconscious and die within a few minutes. Blood agents are non-persistent and will probably
Choking Agents: attack the lungs and respiratory system. They enter the body by inhalation. They
produce immediate symptoms of coughing tears, nausea, and choking. Delayed effects occur after two
to four hours. Delayed effects are painful cough, severe fatigue, rapid and shallow breathing shock, and
frequently, death. Choking agents re non-persistent and will not remain for long in an area.