Dust generated while grinding and processing cannabis, including particulate and biologically active material measured in production areas.
Evidence
A 2026 NIOSH health-hazard evaluation investigated potential cannabis-dust exposure during grinding and processing after reports of job-related asthma and allergic sensitization; the evaluation measured particulates, endotoxins, and surface cannabinoids during grinding and pre-roll production.
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Description · 1Management at a cannabis processing and retail facility requested a health hazard evaluation of potential exposure to cannabis dust during grinding and processing of ground cannabis. These concerns came from reports of workers in the cannabis production industry developing job-related asthma and allergic sensitization to cannabis. ... We measured particulates in the air during grinding and pre-roll production.
The NIOSH HHE found dust exposures during cannabis grinding and pre-roll production, notes that no specific occupational exposure limits exist for cannabis dust, and reports that the particulates can release endotoxins and cannabinoids when plant matter is disturbed.
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page 10 · Our Results; Particulate Exposures · 1Our results from particulate monitoring indicate that there are dust exposures during certain cannabis processing activities that disturb plant matter, such as grinding and making pre-rolls, but there are no specific OELs that can be used to evaluate these exposures. The particulates produced during these tasks are likely a major mechanism by which endotoxins and cannabinoids are released when plant matter is disturbed.
The June 2026 NIOSH report found that particulate levels were highest at the grinding and pre-roll workstation, and that employees associated scratchy throat, cough, hives, rash, or irritated nose with grinding or dry sifting/kiefing, tasks more likely to create cannabis dust.
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page 3 · Our Key Findings · 1–3Particulate levels were higher at the grinding and pre-roll production workstation compared with other work areas. ... Symptoms were associated with grinding and dry sifting/kiefing. These are tasks more likely to create cannabis dust.
Current NIOSH clinical guidance identifies cannabis-industry workers as at risk for work-related asthma and notes that symptoms such as wheezing, coughing, chest tightness, and shortness of breath may improve away from work; it recommends early recognition and reducing or eliminating causative workplace exposures.
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Emerging industries can bring new respiratory risks; Recognizing asthma might be work-related · 1–2A 2025 paper identified 30 work-related asthma cases ... in the legalized cannabis industry ... Study results concluded that cannabis workers are at risk for work-related asthma. ... Workers with work-related asthma often find that their symptoms improve when they are away from work.