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Under state and federal occupational safety laws, employers have a general duty to provide a safe and healthy workplace. That duty includes taking reasonable steps to keep it free of any recognized hazards that might hurt or injure workers. In this regard, cannabis employers and employees should be aware of a previously unrecognized potential hazard that is unique to their workplace: cannabis-aggravated asthma attacks and new onset cannabis-occupational asthma.

A recent study of Washington State workers’ compensation claims revealed that cannabis employees can, and have, experienced asthma attacks and/or related symptoms while performing a variety of cannabis jobs: measuring, packaging, weighing, trimming, or otherwise processing commercial cannabis. (Information on the study appears at the end of this blog post.) While the study is limited in scope, and further research is needed to fully understand the link between cannabis and asthma, it nonetheless highlights real and documented cases of asthma associated with cannabis work.

A few of these cases are particularly illustrative of the asthma-related risks posed by cannabis workplaces and jobs:

  • A man in his 20s with no previous symptoms or history experienced asthma-related symptoms working at a cannabis grow operation. His symptoms disappeared during his 2-year hiatus from cannabis work, but they immediately returned when he returned to similar work. The study suggests that this “strongly suggest[s] that the symptoms are specific to exposures that occurred while working in cannabis grow operations.”
  • A man in his 20s, whose responsibilities included weighing and packaging cannabis in an area with little ventilation, experienced allergy-like symptoms and, eventually, wheezing, shortness of breath, and tightness in his chest.
  • A man in his 30s experienced coughing, wheezing, and shortness of breath as he chopped and ground dried cannabis.
  • A man in his 20s developed wheezing, coughing, and shortness of breath while exposed to a mold or mildew growing on the cannabis plants he trimmed. His symptoms stopped after treatment and he remained symptom-free by wearing a mask while trimming.

These and other identified cases of asthma attacks or new onset asthma related to cannabis workplace exposures emphasize four key potential sources of asthma in the cannabis workplace: (1) exposure to cannabis plants, “dust” caused by trimming or chopping dried cannabis, or smoke; (2) exposure to mold spores found on cannabis plant materials or containers; (3) exposure to various chemicals related to cannabis cultivation, processing, manufacture, and testing; and (4) various combinations of the above.

While there are not currently prescribed specific measures that have to be taken by cannabis employers, enforcing agencies might assert that this new information is enough to trigger some obligation to do something about it. Cannabis employers are strongly encouraged to identify and implement protective measures to avoid unnecessary asthma-related risks in the workplace and undue liabilities. Below is a non-exhaustive list of such measures:

  • Inform employees of key asthma-related symptoms: teary eyes, sneezing, runny nose, eye irritation, coughing, wheezing, shortness of breath, tight chest.
  • Encourage employees to report asthma-related symptoms and to inform their healthcare provider if they experience such symptoms.
  • Implement proper storage and processing procedures to avoid and identify mold growth.
  • Train employees to understand and properly use the various chemicals involved in your cannabis business operations.
  • Ensure that the workplace is properly ventilated.
  • Offer and encourage employees to use of masks and/or gloves while they work with cannabis.
  • Washington employers should take advantage of free safety consultations offered by the Washington State Department of Labor & Industries (Request Consultation (

In addition, the Washington Department of Labor & Industries recently published a resource to help facilitate employee awareness of these risks: Marijuana and Work-Related Asthma

Study of Washington State Workers’ Compensation Claims: Carolyn Reeb-Whitaker, Claire R. LaSee & David K. Bonauto (2022), Surveillance of work-related asthma including the emergence of a cannabis-associated case series in Washington State, Journal of Asthma, 59:8, 1537-1547, DOI: 10.1080/02770903.2021.1955379.

The legal issues impacting workplaces are ever changing (Employment Law in Motion!) and since publication, new or additional information not referenced in this blog post may be available.

This article is provided for informational purposes only—it does not constitute legal advice and does not create an attorney-client relationship between the firm and the reader. Readers should consult legal counsel before taking action relating to the subject matter of this article.

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