Bioaerosol Exposures and Respiratory Diseases in Cannabis Workers

Abstract

Purpose of review: This review investigates occupational inhalation hazards associated with biologically derived airborne particles (bioaerosols) generated in indoor cannabis cultivation and manufacturing facilities.

Recent findings: Indoor cannabis production is growing across the US as are recent reports of respiratory diseases among cannabis workers, including occupational asthma morbidity and mortality. More information is needed to understand how bioaerosol exposure in cannabis facilities impacts worker health and occupational disease risk. Preliminary studies demonstrate a significant fraction of airborne particles in cannabis facilities are comprised of fungal spores, bacteria, and plant material, which may also contain hazardous microbial metabolites and allergens. These bioaerosols may pose pathogenic, allergenic, toxigenic, and pro-inflammatory risks to workers. The absence of multi-level, holistic bioaerosol research in cannabis work environments necessitates further characterization of the potential respiratory hazards and effective risk prevention methods to safeguard occupational health as the cannabis industry continues to expand across the US and beyond.

Keywords: Aeroallergens; Bioaerosols; Cannabis Controlled Environment Agriculture (CEA); Cannabis Manufacturing; Microbial Inhalation Hazards; Occupational Respiratory Exposure.

Fig. 1

Bioaerosols in cannabis indoor work environments. The cultivation, post-harvest dry/cure, processing, pre-roll manufacturing, and packaging operations all generate unique bioaerosols that vary in composition and size, as well as vary within the operational activity and over time. These airborne biological materials may be harmful, neutral, or potentially beneficial to worker health. Sources for these bioaerosols include cannabis plant matter, microorganisms associated with the plant, building materials, substrates, and post-harvest spoilage, irrigation water and its delivery system, growing substrate and amendments, surfaces, floors, ceilings, walls, HVAC system (ventilation and humidity controllers), and the workers themselves

Fig. 2

Exposure to complex bioaerosol constituents relevant to cannabis workplaces may contribute to diverse respiratory and systemic effects. Cannabis cultivation and manufacturing facilities harbor airborne bacteria, fungi, plant matter, and other bioaerosol constituents. Airborne pathogens may be inhaled and could result in infection, particularly in susceptible individuals. Other bioaerosol constituents like microbial metabolites and protein allergens are associated with non-infectious and allergenic respiratory diseases. The complex nature of bioaerosols, challenges assessing worker exposure, lack of diagnostic and research tools, and the Schedule I status of cannabis all contribute to the limited data available to directly connect cannabis-relevant bioaerosol exposure to respiratory disease in workers. Therefore, clear causal relationships between bioaerosol exposure and respiratory effects are not fully elucidated