The Cannabis Industry and Work-related Asthma and Allergies

In January 2022, there were about 428,000 people working in the legal cannabis industry across the country.[1] Workers in the cannabis industry face potential workplace hazards, including exposure to:

• Bacteria, mold, and other fungi resulting from high humidity.
• Wet conditions and poor ventilation in work environments.
• Endotoxins (bacterial cell wall components released when certain bacteria disintegrate).
• Organic particulate matter and dust from the plants. This is more likely to occur if cannabis production and processing tasks are not properly controlled.

Sensitization to proteins from cannabis plants may pose a risk for the development of allergic responses.

The 2022 death of a cannabis industry worker in Massachusetts sparked concerns about these biological occupational exposures. The Occupational Safety and Health Administration (OSHA) investigated the incident as a possible work-related asthma death. The Massachusetts Department of Public Health and NIOSH recently published a Fatality Assessment and Control Evaluation (FACE) report. It highlights key contributing factors in the fatality.

In the report, the Massachusetts FACE investigators developed recommendations for employers to prevent similar occurrences. They include:

• Assess and control hazardous materials in the workplace, including asthmagens (substances that cause asthma).
• Properly train all workers about hazardous materials in the workplace.
• Develop and apply a comprehensive safety and health program that addresses:
  • Hazard recognition.
  • Avoidance of unsafe conditions.
  • Proper use of equipment.
• Implement a medical surveillance program to monitor the health of their workers.

Work-related Asthma and Allergies

NIOSH investigators have conducted several Health Hazard Evaluations (HHEs) at cannabis growing and processing worksites.[2] In these investigations, scientists evaluated exposures to chemical and biological hazards and psychosocial stressors. In a 2022 report, NIOSH investigators found that workers cultivating, harvesting, and trimming cannabis plants had health and safety concerns. They also reported allergic and irritant symptoms that they believed were associated with their work. [3] Cultivation and harvesting employees reported symptoms including stuffy nose or sinus problems, runny nose, skin rash, and red or irritated eyes. Frequently reported symptoms among trimming employees were stuffy nose or sinus problems, headaches, and runny nose.[4]

Challenges and Knowledge Gap

The Association of Occupational and Environmental Clinics (AOEC) has recognized cannabis dust as both an asthmagen and sensitizer.[4] However, challenges exist when diagnosing cannabis allergy.

• Cannabis allergens vary based on the geographic region where the cannabis originated.
• Previous exposure to cannabis and cross-reactivity to plant allergens (such as peach, tomato, and certain nuts) further complicate diagnosis. This makes it difficult to determine what contributed to an allergic response.
• Cannabis strain differences can influence:
  • The amount of tetrahydrocannabinol (THC) present.
  • The amount and type of allergens present. Some individuals can develop reactions to specific strains but not to others.
• Currently, there is no standard test to diagnose cannabis allergy. Individuals should work with an allergist to further understand the specific cause of their symptoms.
• Legal and ethical concerns may contribute to an employee’s willingness to seek medical assistance. The local legal status for cannabis use may make workers uncomfortable approaching their healthcare provider.

While research in the field of cannabis allergy is growing, there are still many unanswered questions. For example, there is no comprehensive list of cannabis allergens. Understanding individual components people may be allergic to may help develop treatments and preventive measures. Additionally, work to develop approaches to diagnose cannabis allergy continues.

Please share your thoughts about future opportunities and needs. What ideas do you have for better understanding work-related asthma and allergies in the cannabis industry? What are the gaps in worker protection practices and controls to prevent work-related asthma and allergies? And how can these be addressed?  We look forward to hearing your thoughts.

More information:

• Evaluation of Potential Hazards During Harvesting and Trimming Cannabis at an Indoor Cultivation Facility

Bradley King, PhD, MPH, CIH, is a senior industrial hygienist in the NIOSH Western States Division and coordinates NIOSH’s Cannabis-and-Work Interest Group.

Catherine Blackwood, PhD, Tara Croston, PhD, and Angela Lemons, MS, are research scientists in the NIOSH Health Effects Laboratory Division.

Sophia Chiu, MD, MPH, and Michael Grant, ScD, CIH, are a physician and an industrial hygienist, respectively, in the NIOSH Division of Field Studies and Engineering.  

Rachel Bailey, DO, MPH, is a physician and Katelynn Dodd, MPH, Reid Harvey, DVM, MPH, and Jacek Mazurek, MD, PhD, are epidemiologists in the NIOSH Respiratory Health Division.

References

[1]. Barcott B, Whitney B, Levenson MS, Kudialis C [2022]. Jobs report 2022. Leafly, https://leafly-cms-production.imgix.net/wp-content/uploads/2022/02/22132544/LeaflyJobsReport2022.pdf.

[2]. Couch JR, Grimes GR, Green BJ, Wiegand DM, King B, Methner MM [2020]. Review of NIOSH cannabis-related health hazard evaluations and research. Ann Work Expo Health 64(7):693–704, https://doi.org/10.1093/annweh/wxaa013.

[3]. NIOSH [2022]. Evaluation of potential hazards during harvesting and trimming cannabis at an indoor cultivation facility. By Grant MP, Wiegand DM, Green BJ, Lemons AR. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Health Hazard Evaluation Report 2019-0152-3381, https://www.cdc.gov/niosh/hhe/reports/pdfs/2019-0152-3381.pdf.

[4]. AOEC [2022]. AOEC Exposure Code System (Keyword: cannabis dust). Association of Occupational and Environmental Clinics, http://www.aoecdata.org/Default.aspx.