Chlordane and a closely related compound, heptachlor, belong to a group of chlorine-based pesticides known as cyclodienes. They were among the first major chemicals to attract national attention and controversy, mainly because of their devastating effects on wildlife and domestic animals. By the 1970s, they had become two of the most popular pesticides for home and agricultural uses (especially for termite control), despite links between these chemicals and the poisoning of birds and other wildlife, pets and farm animals, as well as links to leukemia and other cancers in humans.

In 1975, environmentalists finally persuaded Environmental Protection Agency (EPA) to issue an immediate temporary ban on most uses of chlordane and heptachlor based on an "imminent hazard of cancer in man." In 1978, when the EPA agreed to phase out most remaining uses of chlordane and heptachlor, the agency stated that "virtually every person in the United States has residues...in his body tissues." Chlordane has now been banned, at least temporarily, for sale or use in the U.S. But potentially dangerous levels of the chemical are still found occasionally in food-stuffs, homes, and the environment.