Review of NIOSH Cannabis-Related Health Hazard Evaluations and Research

Abstract

Since 2004, the National Institute for Occupational Safety and Health (NIOSH) has received 10 cannabis-related health hazard evaluation (HHE) investigation requests from law enforcement agencies (n = 5), state-approved cannabis grow operations (n = 4), and a coroner’s office (n = 1). Earlier requests concerned potential illicit drug exposures (including cannabis) during law enforcement activities and criminal investigations. Most recently HHE requests have involved state-approved grow operations with potential occupational exposures during commercial cannabis production for medicinal and non-medical (recreational) use. As of 2019, the United States Drug Enforcement Administration has banned cannabis as a Schedule I substance on the federal level. However, cannabis legalization at the state level has become more common in the USA. In two completed cannabis grow operation HHE investigations (two investigations are still ongoing as of 2019), potential dermal exposures were evaluated using two distinct surface wipe sample analytical methods. The first analyzed for delta-9-tetrahydrocannabinol (Δ9-THC) using a liquid chromatography and tandem mass spectrometry (LC–MS–MS) method with a limit of detection (LOD) of 4 nanograms (ng) per sample. A second method utilized high performance liquid chromatography with diode-array detection to analyze for four phytocannabinoids (Δ9-THC, Δ9-THC acid, cannabidiol, and cannabinol) with a LOD (2000 ng per sample) which, when comparing Δ9-THC limits, was orders of magnitude higher than the LC–MS–MS method. Surface wipe sampling results for both methods illustrated widespread contamination of all phytocannabinoids throughout the tested occupational environments, highlighting the need to consider THC form (Δ9-THC or Δ9-THC acid) as well as other biologically active phytocannabinoids in exposure assessments. In addition to potential cannabis-related dermal exposures, ergonomic stressors, and psychosocial issues, the studies found employees in cultivation, harvesting, and processing facilities could potentially be exposed to allergens and respiratory hazards through inhalation of organic dusts (including fungus, bacteria, and endotoxin) and volatile organic compounds (VOCs) such as diacetyl and 2,3-pentanedione. These hazards were most evident during the decarboxylation and grinding of dried cannabis material, where elevated job-specific concentrations of VOCs and endotoxin were generated. Additionally, utilization of contemporary gene sequencing methods in NIOSH HHEs provided a more comprehensive characterization of microbial communities sourced during cannabis cultivation and processing. Internal Transcribed Spacer region sequencing revealed over 200 fungal operational taxonomic units and breathing zone air samples were predominantly composed of Botrytis cinerea, a cannabis plant pathogen. B. cinerea, commonly known as gray mold within the industry, has been previously associated with hypersensitivity pneumonitis. This work elucidates new occupational hazards related to cannabis production and the evolving occupational safety and health landscape of an emerging industry, provides a summary of cannabis-related HHEs, and discusses critical lessons learned from these previous HHEs.

Occupational Allergies to Cannabis

“…The growth of the cannabis industry has focused the attention of employee unions, state public health agencies such as the Colorado Department of Public Health and Environment (CDPHE), and federal government agencies such as the National Institute for Occupational Safety and Health (NIOSH) on workplace safety and health hazards. 26,27 In states such as Colorado, where medicinal and adult nonmedical use of cannabis is legal, specific guidelines have been established to ensure worker safety in this evolving economic endeavor. 26 Although these recommendations are broad, they are intended to assist in identifying specific hazards present in the industry and are somewhat tailored to the practices within the cannabis industry.…”

“…Although, cannabis cultivation and harvesting operations are analogous to any other plantbased agricultural and manufacturing practices, recent investigations have revealed unique occupational safety and health considerations that need to be considered. 27 In a recent study conducted by the researchers at the Colorado School of Public Health, potential respiratory hazards and health effects were among the most frequently reported concerns by cannabis cultivation workers. 28 Figure 1 illustrates the occupational workflow within a contemporary cannabis grow facility, as well as the associated exposure risks, although specific practices may vary owing to the dynamic nature of the industry.…”

Cannabis and work: Need for more research

“…64 In cannabis industry workplaces, NIOSH evaluations have found Botrytis cinerea, a cannabis fungal pathogen associated with hypersensitivity pneumonitis, and widespread contamination of work surfaces by various cannabinoids, highlighting the need to consider biological contamination in cannabis industry exposure assessments. 65 Further exposure assessment research is needed.…”

“…These workers can be exposed to chemical hazards (flammable liquids and pesticides); biological hazards (fungi, bacterial endotoxins, and plant‐based allergens); and physical hazards (repetitive motions, ultraviolet light, noise, and compressed gases) 64 . In cannabis industry workplaces, NIOSH evaluations have found Botrytis cinerea , a cannabis fungal pathogen associated with hypersensitivity pneumonitis, and widespread contamination of work surfaces by various cannabinoids, highlighting the need to consider biological contamination in cannabis industry exposure assessments 65 . Further exposure assessment research is needed.…”

Exposure to dust, endotoxins and microbes in Finnish vegetable greenhouses

“…Tomatoes and cucumbers account for 80% of the 100 million kilos of annual total production volume. Another reason that greenhouse production is a trending topic is that in recent years, new forms of indoor plant production have emerged, including small-scale private greenhouses, urban roof cultivation [1] and the cultivation of medicinal cannabis [2]. Rather than chemical plant protection products, biological agents are now almost exclusively used for protecting tomato and cucumber plants.…”