chlordane

Chlordane is a synthetic organochlorine pesticide that exists as a mixture of chlorinated cycloalkane isomers, including cis-chlordane and trans-chlordane. It was produced and marketed in the mid-20th century for termite control, wood protection, and various agricultural pest-management uses. Technical chlordane was widely used for decades before regulatory actions reduced or ended its uses in many countries.

Chlordane is highly persistent in the environment and tends to bind strongly to soil and sediments. It degrades very slowly and is lipophilic, leading to accumulation in the fatty tissues of animals and potential long-term exposure through the food chain. Because of these properties, it is broadly considered a persistent organic pollutant with regulatory measures restricting its use.

Health and ecological concerns have driven regulatory actions. Chlordane can affect the nervous system and liver in exposed organisms, and there is concern about cancer risk from chronic exposure. Wildlife and aquatic organisms can be especially sensitive, and residues can remain in soils, buildings, and old treated wood for many years.

Regulatory status and legacy: In the United States, the Environmental Protection Agency canceled registrations for all chlordane uses in 1988; many other countries followed with bans or severe restrictions. As a result, chlordane production has declined and is largely banned or restricted worldwide, with remaining risks confined to legacy residues in the environment and in existing structures or materials.