NIOSH Evaluates Health Concerns Among Cannabis Facility Employees
Employees at a cannabis processing and retail facility reported work-related health symptoms such as scratchy throat, cough, hives, rash, and nasal irritation while grinding and sifting dry cannabis, according to a recent health hazard evaluation (HHE) report published by NIOSH. Agency staff members who visited the site in March 2024 and September 2025 measured higher levels of airborne particulate matter in the grinding and pre-roll production areas, as well as cannabinoids on surfaces throughout the facility. NIOSH also found employee exposure to endotoxins in air below ACGIH’s Threshold Limit Value of 90 endotoxin units per cubic meter of air, averaged over an eight-hour shift. There is not currently a NIOSH recommended exposure limit or OSHA permissible exposure limit for endotoxins, and there are no occupational exposure limits for cannabinoids sampled on surfaces or in air.
The supporting technical information for the HHE report explains that between one and two employees typically performed production work, while the remaining six to seven worked in the facility’s retail area. Employees tasked with production used a tabletop machine to grind dried cannabis flower buds for processing into pre-rolls or essential oil. To make pre-rolls, ground material would be weighed, placed in a vibrating shaker, and poured into paper cones, which were twisted shut. Essential oil was extracted through a process known as “kiefing,” in which buds were placed in a tumbler to extract the trichomes, or kief, the part of the cannabis plant containing the highest concentration of cannabinoids and terpenes. The kief could then be sifted, heated in a decarboxylation oven, and pressed to extract the oil.
Employees wore nitrile gloves while grinding and making pre-rolls. They were also required to wear gloves and face masks during kiefing, dry-sifting, and pressing. Tyvek suits were provided for voluntary use. One employee who reported a rash found their symptoms stopped after they started wearing a Tyvek suit while grinding, dry-sifting, and kiefing.
The HHE report stresses that face masks are not NIOSH-approved respirators and are not designed to filter respirable particles, such as those generated in cannabis processing. NIOSH recommends that the employer train workers to use wet methods or high-efficiency particulate air (HEPA) filter vacuums for cleaning. If HEPA-filtered vacuums are used, the agency notes that the employer may consider respiratory protection for use during tasks that could put dust into the air, like emptying vacuum bags.
The long-term health effects of cannabis exposure via ingestion and dermal exposure are unknown, the report states, “making it important to use strict hand hygiene and cleaning practices to prevent unnecessary contact.” Employees should be trained to remove their gloves and wash their hands before using the restroom, eating, smoking, or entering nonproduction areas of the facility. High-touch surfaces should be regularly cleaned with wet methods, such as wipes with 70 percent alcohol.
NIOSH also recommends that employees report work-related symptoms and health concerns to their employer and healthcare providers and that the employer consider setting up a medical surveillance program for work-related asthma and allergies. The HHE report also advises the employer to address unrelated issues observed by NIOSH personnel during the agency’s evaluation, such as training employees on the safe handling of cleaning alcohol.
The report may be downloaded as a PDF from NIOSH’s HHE report library.
Related: “The Cannabis Industry: A Medical Perspective,” an article from the February 2024 issue of The Synergist, explores the occupational health and safety considerations within the cannabis industry, aiming to shed light on best practices, regulations, and the importance of prioritizing the well-being of workers and the need for standards.