Pentachlorophenol (PCP) is a member of the substituted halogenated aromatic family of pesticides, many of which exhibit insecticide and fungicide activity. In addition, PCP and it's products are toxic to plants, making them useful as defoliants and general herbicides. Primary uses of PCP include protection of timber from fungal rot and wood-boring insects. The mechanism of action of PCP is believed to be inhibition of the formation of ATP by uncoupling oxidative phosphorylation.