The death of an employee early this year at a licensed cannabis facility in Massachusetts is calling attention to the very real threat that the job poses to the health of some workers in the relatively new industry.
Lorna McMurrey, 27, died three days after being admitted to the hospital on Jan. 7 of “occupational asthma due to exposure to ground cannabis” in a cultivation facility in Holyoke for the brand Trulieve, according to an Occupational Safety and Health Administration report.
The OSHA inspection also revealed that employees in the “flower production” area “were not provided effective information and training on the hazards involved in the cannabis production and grinding process.”
Occupational asthma occurs when people inhale fumes, gases, dust, or other harmful substances in their workplace that cause inflammation in their respiratory tract. Symptoms may include coughing, wheezing, shortness of breath, and chest tightness, all of which could result in death in severe cases. Common occupational irritants include ammonia, sulfur dioxide, latex, mold, hydrochloric acid, animal proteins, and flour (which can lead to what’s known as baker’s asthma).
In many cases, people who have occupational asthma also have allergies that may trigger their respiratory symptoms. This is called allergic asthma, and it affects about 60% of people with the condition.
Occupational asthma has become the most common work-related lung disease in developed nations, according to the American Academy of Allergy, Asthma & Immunology, and is estimated to represent up to 15% of all asthma cases in the US. People who work in the healthcare, construction, agriculture, forestry, and manufacturing industries know the risks all too well; research shows the highest proportion of cases occur in these fields.
However, researchers told BuzzFeed News the relationship between respiratory diseases and cannabis exposure in the workplace is complicated — many other factors, such as the presence of other irritants like mold and pesticides and personal cannabis use, could play a role in workers’ health issues.
McMurrey’s death suggests occupational asthma could be a problem in the burgeoning cannabis industry, which adds thousands of employees each year. As legalization expands, experts anticipate the condition may become more common among workers in indoor grow facilities and they say current estimates of its prevalence are likely underreported.
In a statement to BuzzFeed News, Trulieve contested several claims from “initial reports,” including that it had only offered employees paper masks, that McMurrey was working in the “flower grinding room,” and that a supervisor told her to continue working after she said she didn’t feel well.
The company said N95 masks were available, that McMurrey was actually working in the “pre-roll area,” and that she had opted to go back to work.
“Trulieve will continue to operate its facilities in a manner that fully protects the health and safety of all employees,” the company said. “We are confident we did so in January and will continue to do so going forward.”
“As with any industry, there are potential occupational hazards and protecting employee health and safety must be the absolute highest priority,” National Cannabis Industry Association cofounder and CEO Aaron Smith wrote. “We hope that was the case in this terrible matter.”
BuzzFeed News could not reach the McMurrey family, but Dave Bruneau, McMurrey’s stepfather, told the Boston Globe that she had asked for a respirator to wear to work several weeks before she died.
“She said the air was full of dust. You could see it and it would stick to your skin and stuff,” Bruneau told the Globe. “My heart fell into my shoes when the nurse at the hospital told me she was brain-dead from a lack of oxygen. I want people to know what happened to her, and I don’t want it to happen to anyone else.”
What to know about occupational asthma
Occupational asthma falls into two categories: work-aggravated asthma, which is the exacerbation of someone’s preexisting asthma symptoms while at work, and new-onset asthma, which occurs when a person without a history of asthma develops symptoms when they work.
New-onset asthma can be broken down into two subcategories, according to Carolyn Reeb-Whitaker, principal investigator for the Occupational Respiratory Disease Surveillance Program in Washington state.
The first is occupational asthma without latency — also known as reactive airways dysfunction syndrome — meaning symptoms begin suddenly after someone is exposed to high concentrations of a chemical, dust, or another substance. The second is occupational asthma with latency, meaning it takes days, weeks, or months before a person becomes asthmatic.
Reeb-Whitaker and colleagues published a study in 2021 that analyzed 784 work-related asthma cases in Washington between 2009 and 2016. The majority of cases involved people with work-aggravated asthma in the healthcare industry. The highest proportion of new-onset asthma cases occurred in the agriculture, forestry, fishing and hunting, manufacturing, and construction fields. Mold; cleaning materials; and dust from hop plants, wood, and cedar were mostly responsible for triggering these cases.
Regardless of the type of occupational asthma a person has, symptoms are usually always worse during work and improve when they’re off the clock. The level of hazard can depend on the intensity and length of exposure and the conditions inside a workplace, like where the ventilation systems are, Reeb-Whitaker told BuzzFeed News.
However, symptoms can persist even when exposure stops, the AAAAI says. It’s also possible to develop occupational asthma even if you’re using protective equipment like respirators, gloves, eye goggles, and exhaust ventilation systems.
People who smoke and have a family history of allergies are more likely to develop occupational asthma, especially to certain irritants like flour, animals, and latex, according to the AAAAI.
Workers who experience allergic asthma typically develop it months or years after prolonged exposure to a substance because it takes time for their immune system to become sensitized to it. This process involves the production of allergic antibodies called IgE that can generate inflammation in the airways, sometimes causing an asthma attack.
However, “it’s a gray fine line between allergy crossing into asthma,” Whitaker said, because both conditions share similar symptoms.
An allergist can help determine if symptoms are allergy- or asthma-related (or both), which is important because early detection and treatment are key to avoid serious reactions. In some cases, steroid-containing inhalers can reduce the risk of asthma attacks, but the primary treatment is to generally avoid the irritant. Otherwise, workers run the risk of permanent lung damage, disability, or death.
As of now, it’s difficult to estimate how big of a problem the rapidly expanding cannabis industry is to workers’ health, said Coralynn Sack, a physician-scientist at the University of Washington studying environmental and occupational lung disease.
Cannabis is still illegal under federal law, complicating the ability to conduct research in the industry, Sack said. Exposure to harmful substances can also vary widely depending on whether it occurs in indoor or outdoor facilities.
We don’t have enough information about the occupational health risks in the cannabis industry. What we do know comes from research in the hop (used to make a variety of products like beer) and hemp textile markets, studies of which have shown high rates of respiratory illnesses among workers. (Both hop and hemp are related to the cannabis plant.)
The cannabis industry prefers indoor grow facilities because it’s easy to control the light, humidity, and temperature for optimal quality and crop yield. But it’s a high-maintenance process that requires intense manual labor, and the conditions foster an environment where different irritants and allergens can thrive.
Watering and drying of cannabis plants leads to bacterial and fungal growth; the curing process can encourage mold; and the grinding, harvesting, and trimming steps release large amounts of volatile organic compounds like terpenes and organic dust that can irritate the respiratory system. Not to mention the chemicals like pesticides that are used during the grow process.
This vast array of toxic substances makes it nearly impossible to determine what’s causing a worker’s symptoms, Whitaker said, but experts “do have a lot of suspicion that cannabis is capable of causing asthma.”
Data shows that inhalation is the primary cause of occupational asthma, but there are published reports of workers experiencing allergic reactions after touching the plant. (There’s no evidence that employees have gotten high during work as a result of inhaling cannabis dust, Sack said.)
A small survey of 31 employees in an indoor grow facility in Seattle found that 71% reported one or more of them work-aggravated symptoms — 65% reported that symptoms affected their respiratory tract, 39% their eyes, 32% their nose, and 26% their skin. Seven of the employees had abnormal lung function tests. Generally, workers with increasing exposure to cannabis dust were more likely to experience occupational asthma.
About half of those surveyed had skin prick tests — exams that check for immediate allergic reactions — that were positive for cannabis.
We really don’t know much about the prevalence of cannabis allergy, but experts say it’s becoming more common as legalization expands in the US.
People can develop allergies to cannabis at any time via inhaling, smoking, touching, or eating the plant. Symptoms vary depending on the method of exposure. Touching cannabis can cause rashes, hives, or swelling, and workers who inhale cannabis dust can experience a runny nose, sneezing, itching, eye swelling, and asthma.
While it’s unclear how much someone needs to be exposed to cannabis to experience occupational asthma or allergies, researchers speculate that high-dose exposures could be as risky as chronic lower-dose ones. For the most part, repeated exposures can lead to progressively stronger responses.
The AAAAI also warns of potentially serious allergic reactions as a result of cross-reactivity — in which proteins in one substance are similar to those found in another — between cannabis and certain foods such as tomatoes, peaches, and hazelnuts, all of which share specific allergy-causing proteins. The clinical term for this is “cannabis-fruit/vegetable syndrome,” and it has been associated with cross-reactivity with tobacco, natural latex, and some plant-based alcoholic drinks.
A standard skin prick test can determine if you’re allergic to cannabis. The only treatment option is to avoid the plant or reduce exposure to prevent a serious reaction.
The other problem with understanding the health risks cannabis workers face is that many of them use the drug recreationally. The survey of Seattle employees found that 97% were recreational users and 81% smoked cannabis several times a day.
The health risks associated with regular cannabis use largely depend on how the drug is consumed, but the good news is that using it on your personal time is not likely to expose you to the same health risks that workers in the industry face.
But Sack and Whitaker said there are some lessons that recreational users can take from all this.
“A recreational user who's only ingesting cannabis has a very low exposure risk compared to someone working in a cannabis processing facility, but nonetheless, they should take care to observe their health symptoms,” Whitaker said. “If they feel that with repeated use they are having respiratory problems, they should talk to their doctor.”