BLISTER AGENTS (VESICANTS)
Blister agents are vesicants (chemicals which causes blisters). They attack the
eyes, lungs, skin, mucous membranes, and blood-forming organs. Blister agents can
be deadly when inhaled in sufficient quantities due to their destructive effect on lung
tissue. Some blister agents do not produce immediate signs and symptoms. A soldier
may be exposed to these agents for several hours before he realizes the danger.
Blister agents can poison food and water and contaminate supplies, making them
dangerous to handle.
a. Types of Blister Agents. The principle blister agents are mustard (HD),
nitrogen mustard (HN), lewisite (L), and phosgene oxime (CX).
b. Methods of Dissemination. Blister agents can be delivered by artillery shell,
mortar shell, rocket, aircraft bomb, and spray. The blister agents can be disseminated
in either vapor or liquid form. The vapor is really tiny droplets rather than a true vapor.
c. Characteristics of Blister Agents. Mustard is an oily liquid ranging from
dark brown (unpurified form) to colorless (purified form). Mustard smells like garlic or
horseradish. Nitrogen mustard agents are oily liquids ranging from colorless to pale
yellow. Some HN agents have a slightly fishy odor while others are odorless. Lewisite
and related vesicants containing arsenic range from brown to colorless and have fruity
to geranium-like odors. Phosgene oxime is colorless. It may be used as a liquid or in
the form of a crystalline solid. Phosgene oxime has a disagreeable, penetrating odor.
Blister agents are persistent, but HD is more persistent than others, especially in cold or
d. Absorption of Blister Agents. Blister agents are absorbed through the
respiratory system, the eyes, and the skin. Although usually not fatal, exposure is
cumulative in effect. Small, repeated doses of HD can cause lung damage severe
enough to result in death. Mustard remaining on the casualty's skin can be a hazard to
other personnel for up to 48 hours.
e. Physiological Effects.
(1) Mustard and HN are readily absorbed through the respiratory system
and through exposed skin. When they come into contact with skin, they produce
redness at the point of contact that is usually followed by blistering and ulceration.
When inhaled, these agents produce inflammation of the lungs and the rest of the
respiratory system. Death is rare and usually results from bacterial infection of the
lungs. The effects on the skin and respiratory system may not be noticeable at the time
of exposure and may be delayed for up to 12 hours. The eyes are affected even if
exposed to an extremely low dosage. There may be no pain or signs at the time of
exposure with redness and inflammation developing in about 20 minutes (HN) to an
hour (HD) later.