Occupational Exposure Assessment of alpha-Pinene and related Monoterpenes

National Institute Of Environmental Health Sciences

Investigators

Abstract

Monoterpenes are a class of naturally occurring volatile organic compounds (VOCs) that consist of 10 carbons and 16 hydrogens in varying arrangements. Along with being constituents of various coniferous tree species, monoterpenes are also present in cannabis plants, hops, and several herb and citrus species. Because monoterpenes are organic compounds that contain distinct, often pleasant and intense, aromas and flavoring profiles; they have, with increased frequency, been integrated into various consumer products, including food and beverages as flavoring agents, and perfumes, cleaning solutions, and air fresheners as fragrance enhancers. Studies that have assessed the effects of monoterpene exposure on worker health have reported associations between monoterpene exposure and acute decreases in lung diffusion capacity, bronchial reactivity, contact allergy and eye irritation. Recent investigations into the association between monoterpene levels and sensory irritation of the nose and throat, which culminated in the establishment of an ACGIH TLV for turpentine and related monoterpenes of 20 ppm, have suggested that the current OSHA PEL and NIOSH REL of 100 ppm may not be adequately protective. While several Northern European studies have examined exposure to monoterpenes in woodworking settings, the range of exposures to monoterpenes US woodworking settings and other occupational settings are poorly understood. In FY23, the study team received IRB approval to begin collecting exposure assessment data for workplace exposures to monoterpenes. Several analytical methods were fully evaluated, including air, dermal, and urine methods. A breath method is currently under evaluation to ensure adequate storage stability and accuracy at exhaled breath-like conditions. The study team also established connections with trade associations, unions, independent consultants, and academic researchers representing the cannabis cultivation and processing, hops cultivation, cleaning worker, woodworker, and flavor and extract manufacturing industries. More than 200 organizations representing cannabis cultivation and processing, flavor manufacturing, pine chemical production, cleaning manufacturing, and cleaning industries have been contacted. The first site visit for this project was conducted at a university to assess monoterpene levels in janitorial workers. Three other site visits are tentatively planned in FY23 to measure monoterpene exposure in janitorial workers and another site visit is tentatively planned to measure monoterpene levels at a cannabis extraction facility in early FY24.