Cannabis Industry Workers Are Developing Work-Related Asthma

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.

Pacheco, Michelle et al.·Journal of occupational and environmental medicine·2025·Preliminary EvidenceRetrospective Cohort
RTHC-07293Retrospective CohortPreliminary Evidence2025RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Retrospective Cohort
Evidence
Preliminary Evidence
Sample
Not reported

What This Study 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.

Key Numbers

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 They Did This

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.

Why This Research 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 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.

What This Study Doesn't 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.

Questions This Raises

  • ?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?

Trust & Context

Key Stat:
30 work-related asthma cases identified, including 2 deaths
Evidence Grade:
Preliminary evidence from passive surveillance data that likely undercounts true cases and lacks denominator data for rate calculations.
Study Age:
2025 study covering cases from state legalization dates through 2023.
Original Title:
Work-Related Asthma in the Cannabis Industry: Findings From California, Massachusetts, Michigan, and Washington.
Published In:
Journal of occupational and environmental medicine, 67(10), 862-868 (2025)
Database ID:
RTHC-07293

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Looks back at existing records to find patterns.

What do these levels mean? →

Frequently Asked 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 More on RethinkTHC

Cite This Study

RTHC-07293·https://rethinkthc.com/research/RTHC-07293

APA

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

MLA

Pacheco, Michelle, et al. "Work-Related Asthma in the Cannabis Industry: Findings From California, Massachusetts, Michigan, and Washington.." Journal of occupational and environmental medicine, 2025. https://doi.org/10.1097/JOM.0000000000003461

RethinkTHC

RethinkTHC Research Database. "Work-Related Asthma in the Cannabis Industry: Findings From ..." RTHC-07293. Retrieved from https://rethinkthc.com/research/pacheco-2025-workrelated-asthma-in-the

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.