A broad spectrum insecticide, for instance, will wipe out all of the insects in its target area. A narrow spectrum insecticide is selective to species. The chemical DDT, banned for sale in the United States since the early 1970s, is a highly persistent chemical and still present in the environment. As DDT degrades, its breakdown product, DDE, is still creating problems. In areas of intensive agriculture, DDE has been found to affect the reproductive systems of developing males in a variety of species, most notably the Florida panther.
Dioxins are another branch of dangerous and persistent chemicals.
The EPA considers the dioxins harmful enough to ban, but this has been fought by several influential industries. Dioxins result from the brekadown of herbicides, but it is also a byproduct of the paper and pulp industry. Herbicides Which kill leaves. Fungicides Affecting seeds and fruit. Rodenticides Intended to kill rodents.