- a potent synthetic insecticide, C14H9Cl5, initially developed in the 1940s to combat insect-borne human diseases and later found to be highly and adversely persistent in the environment: agricultural use now prohibited in many countries, including, since 1972, the United States.
- dichlorodiphenyltrichloroethane; a colourless odourless substance used as an insecticide. It is toxic to animals and is known to accumulate in the tissues. It is now banned in the UK
