CHLORINATED HYDROCARBONS

One example, DDT, is an insecticide. It was extensively used in World War II to delouse personnel and to prevent the spread of plague and other insectborne diseases. Today, its use is restricted because of its toxicity and its very long life.

Suspected carcinogen with experimental tumors of the liver, lung, skin, and blood-forming tissues. The substitution of a chlorine (or other halogen) atom for a hydrogen greatly increases the anesthetic action of the aliphatic hydrocarbons and increases the range of their systemic effects. In many cases, the chlorine derivative is quite toxic. In general, the unsaturated chlorine derivatives are more narcotic but less toxic than the saturated derivatives. In the saturated group, the narcotic effect is proportional to the number of chlorine atoms. This relationship is not true for toxicity. In dealing with these chlorinated hydrocarbons, it must be remembered that a toxic action may result from repeated exposure to concentrations that are too low to produce a narcotic effect, and that, consequently, are too low to gve warning of danger. InQvidual susceptibility varies widely. Certain workmen may be seriously affected by concentrations that seem to have no effect on fellow employees at the same exposure. In general reactivity decreases with greater substitution of halogen for hydrogen atoms. Halogenated (i.e., fluorine-, chlorine-, or bromine-containing) acetylene compounds are unstable and should be treated as explosives. Lightly substituted haloalkanes are highly flammable and can react with Qvalent light metals to form dangerously reactive products. Lightly substituted haloalkenes are highly flammable, peroxidizable, and may polymerize violently. When heated to decomposition they emit highly toxic fumes of phosgene. They may react violently with Al, liquid O2, K, and Na.