Occupational Exposure to Particulate Matter and Volatile Organic Compounds in Two Indoor Cannabis Production Facilities.

Legal commercial cultivation and processing of cannabis is a rapidly growing industry in multiple countries. However, to date little effort has been made to characterize and identify the various occupational hazards that workers may be facing in the cannabis production industry, including airborne contaminants that may affect the human respiratory system. In the current study, we quantified occupational exposures to particulate matter (PM) and volatile organic compounds (VOCs) in various task zones of two indoor cannabis facilities in Washington State. Full-shift (8-h) area measurements of PM and VOCs were collected in each task zone. Measurement devices were placed near the employee's work area in order to attempt to estimate the personal exposure to the contaminants. In each task zone we measured particle number concentration, particle mass concentration (PMC), cumulative size distribution of the particles, and total terpene mass concentrations. The mean PMCs were greater in task zones that required the employees to manipulate the cannabis plants and materials. The arithmetic mean PMC for the trim task was 60 µg m-3, preroll task was 45 µg m-3, grow task was 42 µg m-3, and the referent office area was 27 µg m-3. When comparing each task zone PMC to the office referent PMC, the trim task, and the preroll task were significantly higher than the referent group (P-values both <0.05). The arithmetic mean terpene mass concentration for the trim task was 36 mg m-3, preroll task was 9.9 mg m-3, grow task was 15 mg m-3, and for the office referent space was 4.9 mg m-3. Compared with the office space, only the trim task area had significantly elevated terpene mass concentrations (P-value <0.01). We observed a weak but statistically significant correlation between PMC and total terpene mass concentrations (rho = 0.42, P < 0.02). Overall, we observed that exposures to respiratory hazards were highest in task zones where cannabis plants and material were manipulated by workers, including the trim, preroll, and the grow task areas. These observations can help inform the employer of the task zones where exposure to respiratory hazards are the highest, and where it may be beneficial to deploy control measures to reduce worker exposures.

Allergic and Respiratory Symptoms in Employees of Indoor Cannabis Grow Facilities.

BACKGROUND: While little is known about the occupational hazards associated with Cannabis cultivation, both historical research in the hemp industry and preliminary data from modern grow houses, suggest that Cannabis workers may be at increased risk of respiratory and allergic diseases. OBJECTIVES: We sought to investigate the association between workplace exposures and health symptoms in an indoor Cannabis grow facility in Washington State, USA. METHODS: We performed a cross-sectional study with all consenting employees in an indoor Cannabis grow facility in Seattle, WA using a questionnaire. The questionnaire gathered data on respiratory, ocular, nasal, and dermal symptoms. A subset of employees with work-related symptoms underwent repeated cross-shift and cross-week measurement of spirometry, fractional exhaled nitrogen oxide (FeNO), and skin prick testing for Cannabis sensitization. Exposure to Cannabis dust was classified based on self-described tasks, expert opinion, and exposure monitoring of particulate matter. Multivariable logistic regression was undertaken to examine associations between exposure to Cannabis dust (classified as low, medium, and high) and health symptoms. Linear mixed effects models examined the relationship between cross-shift and cross-week changes in spirometry and FeNO. RESULTS: Ninety-seven percent (97%) of the employees (n = 31) surveyed were recreational cannabis users, with 81% (n = 25) smoking cannabis multiple times per day. Twenty-two (71%) employees reported one or more work-related symptoms: 65% respiratory, 39% ocular, 32% nasal, and 26% dermal symptoms. There was a trend toward increased likelihood of work-related symptoms with increasing exposure to Cannabis dust, although none of these results were statistically significant. Of the 10 employees with work-aggravated symptoms, 5 had borderline-high or high FeNO, 7 had abnormal spirometry, and 5 had evidence of Cannabis sensitization on skin prick testing. FeNO increased by 3.78 ppb (95% confidence interval 0.68-6.88 ppb) across the work-week and there was a trend toward cross-week and cross-shift reduced airflow. CONCLUSIONS: We found a high prevalence of work-related allergic- and particularly respiratory symptoms in the employees of one indoor Cannabis grow facility in Washington State. A high proportion of employees with work-aggravated symptoms had findings consistent with probable work-related asthma based on high FeNO, airflow obstruction on spirometry, and Cannabis sensitization on skin prick testing. However, due to the high incidence of recreational cannabis use among these workers, the relative influence of occupational versus recreational exposure to Cannabis dust on the respiratory health and sensitization status of these workers could not be resolved in this study.