(b) Organophosphates. This group of pesticides has a wide range of
mammalion toxicity from a very low order, as in malathion; through a moderate order, as
in diazinon; to a high order, as in parathion. This group of chemicals inhibits
cholinesterase, an enzyme essential to the proper functioning of the nervous system.
Mammalion poisoning from organophosphates pesticides, therefore, involves the central
nervous system. Symptoms of poisoning may include gastrointestinal discomfort,
salivation, profuse sweating, and difficulty breathing. As with poisoning due to
chlorinated hydrocarbons, the immediate cause of death is usually respiratory failure.
(c) Carbamates. The insecticides in this group also inhibit the action
of the cholinesterase and, like the organophosphates, exhibit a wide range of toxicity
and hazard. Baygon, for example, has 5 to 8 times the toxicity of carbaryl.
b. Rodenticides. The materials in this group are inorganic and organic
chemicals, but the uses and modes of action are sufficient to justify consideration of
rodenticides as a separate group. Those formulated from heavy metals and plant
products have been mentioned above. These have been the cause of most human
poisoning associated with rodenticides. Another group of chemicals used widely in
rodent-control programs today comprises the anticoagulants, derivatives of coumarin
orindiandione. One of the early members of this group is known as "Warfarin," which is
being supplemented in the military supply system by other anticoagulants in water-
soluble formulations. In addition to causing capillary damage, these chemicals interfere
with the formation of prothrombin, resulting in extensive internal hemorrhages. These
chemicals do, however, have the advantage of low acute toxicity; consequently, in the
concentrations recommended, repeated ingestion over a period of several days is
required to produce lethal poisoning in mammals, including man. Accidental or
deliberate ingestion of these anticoagulants, particularly of the concentrates, may lead
to death. Depending on systemic levels reached, repeated prolonged exposure may
result in disease conditions ranging from prolonged bleeding from minor cuts to serious
Fumigants. These chemicals are used for specialized problems in rodent
control as well as for insect control in selected situations.
d. Herbicides and Fungicides. Herbicides and fungicides fall into the same
general chemical classifications as insecticides. They exhibit similar characteristics,
having a wide range of toxicities (Table 1-2). The hazards are similar to those of other
pesticides and are included in the information on the container label.
STORAGE AND DISPOSAL OF PESTICIDES
a. Storage Requirements. All pesticides must be stored in a secure space
that can be locked, in order to prevent access by untrained and unauthorized persons.
In addition to security, the following criteria are important in storing pesticides.