Cannabis allergies are more common than many people may think. The cannabis plant is rich with pollen, which can trigger allergies in humans and cause symptoms like congestion, runny nose, sneezing, watery or red eyes, post-nasal drip, and itchy eyes or nose. It can also cause skin irritation like rashes, hives, and itching, and in more serious cases, it can cause difficulty breathing or asthma.
According to a study published earlier this year, working in a cannabis grow facility can make people more likely to develop work-related allergic and respiratory symptoms.
The study, entitled “Allergic and Respiratory Symptoms in Employees of Indoor Cannabis Grow Facilities,” surveyed 31 employees of a single large-scale grow facility in the state of Washington, and found that 71% of the employees reported one or more work-related symptoms. Of these, five had evidence of cannabis sensitization on skin prick testing.
“While little is known about the occupational hazards associated with cannabis cultivation, both historical research in the hemp industry and preliminary data from modern grow houses, suggest that Cannabis workers may be at increased risk of respiratory and allergic diseases,” the researchers wrote.
Of those surveyed, 97% are recreational cannabis users, and 81% are users who smoke multiple times per day. According to the researchers, “a high proportion of employees with work-aggravated symptoms had findings consistent with probable work-related asthma based on high FeNO (fractional exhaled nitrogen oxide), airflow obstruction on spirometry, and cannabis sensitization on skin prick testing.”
The study was perhaps limited by the fact that it only polled the employees of a single indoor cannabis grow facility in Washington, and there was no control population for comparison. In addition, 26% of the employees already had a pre-existing diagnosis of asthma.
The researchers also stated that because of the “high incidence of recreational cannabis use” among the workers, the “relative influence of occupational versus recreational exposure to cannabis dust on the respiratory health and sensitization status of these workers could not be resolved in this study.”
Risk level varies according to job function
The study was carried out from October 2018 to January 2019. The employees were given a questionnaire to gather data about respiratory, ocular, nasal, and dermal symptoms. They also went through a series of tests to examine their lungs and skin. Employees were also given a short questionnaire to fill out on each day of data collection, which recorded their tobacco and cannabis use during the previous 24 hours.
The facility in question is a tier-three licensed facility, the largest size (10,000 to 30,000 square feet) in the industry, and it uses non-organic cultivation methods. The facility dries plant material, trims and packs buds for sale, and crushes plant material for use in smoking products. It also performs the extraction of plant material using propane or thermal expeller techniques.
The researchers characterized the specific tasks in the facility according to risk. Tasks such as “office” and “labeling” were considered low risk, the medium-risk section included “packing” and “preroll,” and high risk included tasks such as grinding, sorting, sifting, and harvesting, among others.
They also stated that “the grow conditions required by the cannabis plant result in many potential irritant and allergic hazards, including herbicides, molds, endotoxins, noxious gases, VOCs, and PM. Workers are exposed to carbon dioxide, carbon monoxide, pesticides, and other airborne contaminants common to agricultural-related industries.”
The researchers that the watering and drying of cannabis plants leads to a significant amount of water vapor in indoor grow regions, providing an ideal devourment for bacterial and fungal growth,” as does the curing process.
In June 2018, doctors in Canada warned that cannabis legalization would likely increase the prevalence of cannabis allergies, in particular among those who work in the industry and are regularly exposed to the plant.