Although the possession, use, and sale of all forms of cannabis are illegal under U.S. federal law, since 2012, multiple states have legalized the retail sale of cannabis for medical and recreational use. Previous research studies have indicated that tetrahydrocannabinol (THC), the principal psychoactive constituent of cannabis, can cause acute and chronic health effects. However, health effects from long-term occupational exposures to cannabis during harvesting and processing are unknown, in part because most studies have focused primarily on nonoccupational settings.
In June 2015, the National Institute for Occupational Safety and Health (NIOSH) received a request for a Health Hazard Evaluation (HHE) from a representative of the United Food and Commercial Workers International Union to evaluate potential health and safety hazards associated with harvesting and processing cannabis at an outdoor farm. The study was published in the Centers for Disease Control and Prevention (CDC) Morbidity and Mortality Weekly Report on March 2.
The first author Dr. Kerton R. Victory, environmental health officer and epidemiologist in the Emergency Preparedness and Response Office of the National Institute for Occupational Safety and Health, is an alumnus of the University of Arizona Mel and Enid Zuckerman College of Public Health where he received his PhD in environmental health sciences.
In response to the request, NIOSH visited the farm in August and October 2015. The farm was located in Washington; the state had legalized cannabis for medicinal use in 1998 and recreational use in 2012. At the time of the HHE, the farm was operated by the owner and three employees. The five-acre farm did not use any pesticides and grew cannabis, vegetables, and fruits.
The findings of this HHE indicated that the employees have exposures to highly repetitive work, most notably during hand trimming activities, which increase workers’ risk for musculoskeletal disorders. Worker exposure to aerosolized Actinobacteria and fungi such as B. cinerea, might also result from processing and hand trimming activities, which can increase the risk for allergic and respiratory symptoms, as has previously been observed in the cannabis processing industry. THC surface wipe concentrations indicated the potential for dermal and ingestion exposures. However, the health implications from long-term occupational exposure to THC are unknown.
Notes from the Field: Occupational Hazards Associated with Harvesting and Processing Cannabis — Washington, 2015–2016. CDC Morbidity and Mortality Weekly Report, March 2, 2018
Kerton R. Victory, PhD; James Couch, PhD; Brian Lowe, PhD; Brett J. Green, PhD