Pentachlorophenol (PCP) is used primarily as a wood preservative. It can be absorbed into the body by all the routes of occupational exposure. It causes local irritation to the eyes and nose, as well as systemic effects that result from its ability to uncouple mitochondrial oxidative phosphorylation. Also, it is fetotoxic and teratogenic during early gestation. Commercial PCP is contaminated with chlorinated dioxins and dibenzofurans, tetrachlorophenols, and hydroxychlorodiphenyl ethers. Some of these impurities are capable of causing chloracne and chronic liver damage. Several areas in PCP's toxicological profile, such as carcinogenesis and mutagenesis, are incomplete. With regard to occupational exposures, precautions should be taken to avoid direct contact and air levels should be kept within acceptable levels.