Chlorinated hydrocarbons
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.
Source: Corrosion-Doctors.org
Wikipedia: https://en.wikipedia.org/wiki/Organochloride