Evaluates the risks to human health and the environment posed by exposure to alpha- and beta-hexachlorocyclohexanes (HCH). These two isomers are by-products in the manufacturing of lindane, and may be present in this pesticide as impurities. Alpha- and beta-HCH are also present in technical-grade HCH, which is used in agriculture and wood protection. Most environmental releases are linked to the use of technical-grade HCH and to the inappropriate disposal of residues produced when lindane is purified.