Hydrocarbons that contain chlorine. These include a class of persistent insecticides that accumulate in the aquatic food chain. Among them are DDT, aldrin, dieldrin, heptachlor, chlordane, lindane, endrin, Mirex, hexachloride, and toxaphene.Chlorinated hydrocarbons were first introduced in the 1940’s after the development of insecticidal properties of DDT. A few of the compounds in chlorination hydrocarbons are pretty steady and have long-term residual effects and represent valuable components where protection is needed for long periods of time. The most damaging effect that chlorinated hydrocarbons have on the human body is the ability to alter the nervous system. For this reason, many of these organic compounds have been prohibited for their harmful effects on not only humans, but the environment.