What molecule am I?
Pentachlorophenol is an old-line pest control agent that came under regulatory pressure decades ago. Beginning in the 1930s, it was used as an insecticide (including for termite control), a defoliant for crops before they were harvested, a wood preservative (notably in telephone poles), and a biocide with numerous other agricultural and industrial uses.
Pentachlorophenol is made by chlorinating phenol at high temperature. In the commercial process, chlorination is incomplete, and the product contains even more toxic impurities such as dibenzo-p-dioxin derivatives. The compound’s odor is similar to that of benzene or phenol; it is sparingly soluble in water and slow to decompose in nature.
Pentachlorophenol’s pervasive toxicity and environmental threats (see the hazard information table) doomed it to severe use restrictions by the 1980s. Today, wood preservation is the only use permitted by the US Environmental Protection Agency. Earlier this year, the EPA proposed to ban it completely. The comment period for this proposal expired in May, and EPA is currently proceeding with canceling the registration
For additional information, see EPA’s information page on pentachlorophenol.
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