Cannabis Industry Workers Are Developing Work-Related Asthma | Research

The takeaway

Across four U.S. states, 30 cases of work-related asthma were identified among cannabis industry workers, with two fatalities, primarily linked to cannabis dust exposure in indoor cultivation.

Cannabis industry workers, employers in cannabis cultivation and processing, occupational health professionals

30 work-related asthma cases identified, including 2 deaths

What the researchers found

Of 30 work-related asthma cases in the cannabis industry, 52% were new-onset asthma and 48% were work-aggravated asthma. Cannabis dust and plant materials were the most common exposure (40.4%), and 69% of cases worked in indoor cultivation or processing. Two deaths occurred.

Why it matters

As the legal cannabis industry expands, occupational health risks are becoming more visible. This is among the first multi-state surveillance data showing that cannabis industry workers face real respiratory hazards, particularly from dust exposure during indoor cultivation and processing.

The numbers in context

30 WRA cases across 4 states. 66.7% aged 18-34. 60% male. 52% new-onset asthma, 48% work-aggravated. 2 fatalities. 40.4% exposed to plant materials (94.7% cannabis dust). 69% worked in indoor cultivation/processing.

How the study worked

Retrospective analysis using data from four state-based surveillance systems (California, Massachusetts, Michigan, Washington), identifying and classifying work-related asthma cases in the cannabis industry from legalization dates through 2023.

What this study cannot tell us

Surveillance data likely undercount cases since reporting depends on workers seeking medical care and physicians recognizing the condition. Only 30 cases across decades of data and four states. No denominator data to calculate incidence rates.

How to read the evidence

Preliminary evidence from passive surveillance data that likely undercounts true cases and lacks denominator data for rate calculations.

When this study was published

2025 study covering cases from state legalization dates through 2023.

The bigger picture

Occupational health protections in the cannabis industry are still developing. These findings suggest that cannabis workplaces need dust control measures, respiratory protection programs, and health surveillance similar to other agricultural and manufacturing settings.

Questions still open

What are the actual incidence rates of respiratory disease among cannabis workers? What engineering controls are most effective for reducing cannabis dust exposure? Are there long-term respiratory effects beyond asthma?

Common questions

What caused work-related asthma in cannabis workers?

The most common exposure was plant materials, with 94.7% of those cases involving cannabis dust or marijuana plant material. Most affected workers (69%) worked in indoor cultivation or processing environments.

How serious were the cases?

About half were new-onset asthma, meaning workers developed asthma for the first time due to workplace exposure. Two workers died from their condition.

Read the original research

Work-Related Asthma in the Cannabis Industry: Findings From California, Massachusetts, Michigan, and Washington.

Journal of occupational and environmental medicine, 67(10), 862-868

View on PubMed ↗Publisher’s paper ↗

Citation

Pacheco, Michelle; Fitzsimmons, Kathleen; Reeb-Whitaker, Carolyn; Rosenman, Kenneth; Flattery, Jennifer; Weinberg, Justine Lew; Reilly, Mary Jo; Yiu, Sarah; Sack, Coralynn; Todorov, Danièle; Harrison, Robert; Dodd, Katelynn E; Sparer-Fine, Emily. (2025). Work-Related Asthma in the Cannabis Industry: Findings From California, Massachusetts, Michigan, and Washington.. Journal of occupational and environmental medicine, 67(10), 862-868. https://doi.org/10.1097/JOM.0000000000003461