α-Pinene is a naturally occurring monoterpene produced by some plants (e.g., pine trees, cannabis, rosemary) and is used as a flavor and fragrance ingredient in addition to being the main constituent in turpentine. Exposure concentrations of α-pinene can reach 27 ppm (α-pinene) or 99 ppm (total terpenes, primarily α-pinene and Δ3-carene) in certain occupational settings, such as softwood lumber processing. Data are insufficient on the long-term effects associated with exposure to α-pinene or turpentine, and occupational exposures are likely to be chronic. Therefore, National Toxicology Program (NTP) carcinogenicity studies were conducted in Sprague Dawley (Hsd:Sprague Dawley® SD®) rats and B6C3F1/N mice to characterize hazard following chronic exposure to α-pinene. An inhalation route of exposure was selected to mimic the primary route of human exposure in occupational settings.
