Dicofol is an organochlorine pesticide that is chemically related to DDT. Dicofol is a miticide that is very effective against red spider mite. One of the intermediates used in its production is DDT. This has caused criticism by many environmentalists; however, the World Health Organization classifies dicofol as a Level II, "moderately hazardous" pesticide. It is known to be harmful to aquatic animals, and can cause eggshell thinning in various species of birds.