Q&A: Here’s What the CDC Has Learned About Cannabis Workplace Hazards

Workplace questions involving cannabis have, for more than a decade, been directed toward the National Institute for Occupational Safety and Health (NIOSH), within the Centers for Disease Control and Prevention. At first, these questions came primarily from law enforcement. But, over the years, cannabis businesses, labor unions, and even a coroner’s office have sought answers. 

The inquiries are things along the lines of: Will I fail a drug test if I’m policing public consumption? Is this greenhouse set up safely for my employees? Sometimes, NIOSH staff answer by phone, other times, they are out in the field. 

For a review newly published in the Annals of Work Exposures and Health, NIOSH shares what the Institute has learned since 2014, during which ten cannabis-related health hazard evaluation (HHE) investigations have been conducted. They have found a number of potential hazards, from gray mold, which is common in vineyards and linked to what’s known as winegrower’s lung, to cannabis-specific ergonomic stressors like pain from trimming leaves by hand. 

The authors write, “Even though the cannabis-related [health hazard evaluation] request numbers are small, the trend is clear. There is a need for occupational safety and health information for an emerging industry. This is a rare opportunity to study the wide array of exposures and health effects from the beginning of an industry instead of retrospectively evaluating relationships after years of exposure.”

Cannabis Wire spoke with lead author James Couch, of NIOSH’s Division of Science Integration, to learn more about their work and how recommendations could be put forth for this nascent industry. (This interview has been edited for length and clarity.)

Cannabis Wire: What exactly is a health hazard evaluation? 

James Couch: These can be requested by either employees, a labor union representative, or a management official, or the company themselves, or someone representing the employer. 

The HHE program plays an important role in NIOSH by identifying those new and emerging workplace hazards. We do those in a number of different ways. Sometimes we can triage it and handle it over the phone and just provide information or have a couple of different teleconferences to answer questions with different groups. And then in other scenarios, which are the basis of this article, we go out to the field. 

Cannabis Wire: What might prompt a request from law enforcement, and what might  prompt a request from, say, a state-licensed cannabis grow operation? 

James Couch: The law enforcement requests have actually changed throughout the years as well. Initially, it was more of: types of confiscation, storage of the banned materials in their warehouses, or testing the materials. So, it was more from a standpoint of the law enforcement aspects. It’s kind of shifted, as it’s become more acceptable from a recreational and medicinal standpoint. The latest one was second hand smoke. What would be potential exposure on, say, a public avenue if there were consumption of cannabis? 

From a state-approved cannabis facility, their questions are probably half and half: Probably half are from a compliance standpoint. They just have questions, they’re just starting up their businesses, they’re trying to figure out how to comply with occupational safety and health regulations and laws. And then there’s probably another half that are interested in ‘What are some of the health effects of some of the unknown variables that we’re dealing with?’ 

Cannabis Wire: What prompted this cannabis review, and why now? 

James Couch: We were actually requested to do this type of review by the journal itself. They were putting together a special issue of occupational safety and health related studies, and they were familiar with the broad spectrum of work that we had done. 

Cannabis Wire: How would you characterize the change in volume of questions that you receive, and concerns regarding workplace exposure?

James Couch: The volume has been actually fairly steady since the first laws started coming in, legalizing at the state level. 

Cannabis Wire: Are you getting outreach from local, state, or federal regulators? Or Canada? Or European regulators that are dealing with cannabis rulemaking?

James Couch: We’ve worked with the State of California. They’ve done a lot of work on trying to get a sense for what they need to include in their occupational safety and health standards. A couple of states have reached out, just kind of asking verification questions of different things that we’ve done, or different methods that we’ve used. There are a couple of things that we’ve done formally, just kind of provide comments to other federal agencies that say, “Hey, we’ve done this type of work, you know, in a certain area, and just for your situational awareness, we’ve done this work and here’s kind of what we found.” Internationally, I don’t think we’ve gotten a lot of questions, maybe just some informal questions. 

Cannabis Wire: Are you doing any work around hemp, now that it’s federally legal? 

James Couch: Both the blessing and the curse of the HHE program is that we’re reliant upon people providing those HHE requests. We just haven’t gotten any from the hemp industry. There’s obviously interest in seeing how the research that we’ve done in both the recreational and medicinal sides of the equation translates or crosswalks to the industrial hemp side. But we just haven’t had any of those requests. However, in Europe, they’ve actually done quite a bit of work with hemp. And so, if we were to do that type of work, we’d draw heavily from the work that Europeans have already done. 

Cannabis Wire:  Let’s talk about the three or four main findings of the review. The first one, you wrote: “Surface wipe sampling results for both methods illustrated widespread contamination of all phytocannabinoids throughout the tested occupational environments, highlighting the need to consider THC form (Δ9-THC or Δ9-THC acid) as well as other biologically active phytocannabinoids in exposure assessments.” What does that mean? 

James Couch: So basically what that means is, we took a wide number of samples across the workplace, whether it be in the production areas, whether it be cultivation, or whether it be non-production areas like cafeterias or break rooms. And what we found was that we were able to find levels of the different cannabinoids, whether it be THC, THC A, CBD, those types of things. We found them on surfaces throughout. 

And so what that means is, that if it’s being contaminated on surfaces, there’s potential for dermal exposure throughout these facilities for these different cannabinoids. And, from a research perspective, we’re not sure exactly how those cannabinoids transfer across the dermal layer. So, this is part of that exposure identification and characterization aspect that we talked about earlier, that we’re just trying to say that these cannabinoids are present throughout the workplace, and just to be thoughtful of that. Having cleaning procedures, and maybe having, you know, uniforms or wearing gloves and those kind of things to help prevent dermal exposures.

Cannabis Wire: Another finding was: “Employees in cultivation, harvesting, and processing facilities could potentially be exposed to allergens and respiratory hazards through inhalation of organic dusts (including fungus, bacteria, and endotoxin) and volatile organic compounds (VOCs) such as diacetyl and 2,3-pentanedione. These hazards were most evident during the decarboxylation and grinding of dried cannabis material, where elevated job-specific concentrations of VOCs and endotoxin were generated.” 

What does that mean for employees in these kinds of places, where growing, harvesting, and processing happens? 

James Couch: There’s a number of different things in the microbiome. You know, this is obviously a plant that’s growing. It does have the potential for fungus, bacterial, and those types of microbes. And so we found positive results for those types of samples. 

The one in Washington, we found Botrytis cinerea, which is commonly known as gray mold, which is of great concern in the industry. But it’s also an occupational hazard. It’s been linked to what’s called ‘winegrowers’ lung’ because that mold likes to also grow on grapes. And so there’s those types of situations that we’re concerned about. 

And then it goes into the volatile organic compounds, which are, more chemicals like diacetyl that have been seen in other industrial settings to cause different types of upper respiratory or lung issues. And we found them in very small amounts, especially in the second HHE, and we want to make sure to let others know: we found these compounds, here’s the different levels that we found, and if you’re going to be doing additional exposure studies, you may want to consider looking for these compounds as well. 

Cannabis Wire: You also wrote: “Additionally, utilization of contemporary gene sequencing methods in NIOSH HHEs provided a more comprehensive characterization of microbial communities sourced during cannabis cultivation and processing. Internal Transcribed Spacer region sequencing revealed over 200 fungal operational taxonomic units and breathing zone air samples were predominantly composed of Botrytis cinerea, a cannabis plant pathogen. B. cinerea, commonly known as gray mold within the industry, has been previously associated with hypersensitivity pneumonitis.” 

What does that mean? 

James Couch: What that boils down to is, when we did the air sampling, we found a wide number of different fungal, bacterial and mold types of species in the air that were available for intake into the workers’ respiratory system. And a number of those have also been associated with respiratory diseases or allergens. And so, again, it’s just an awareness that we found these types of microbiomes available inside of the workplace. 

If people are looking at their workplace, they’re finding folks that have allergies or asthma or occupational related asthma issues, this may be one of these things that’s causing that. There are a large number of things in the air because this is a very active biological workplace. There’s plants everywhere. And there’s also people everywhere. And so this was kind of a new area of occupational safety and health research. We traditionally haven’t looked at this as much. And so we found this a great opportunity to try to characterize this workplace by doing this type of sampling.

Cannabis Wire: What are some examples of ergonomic stressors and psychosocial issues that you encountered? 

James Couch: A lot of the ergonomic stressors that are going to be present in these types of workplaces are actually very similar to what we would see in other agricultural workplaces or greenhouse scenarios. If you have large plants that may be to be moved—as the plants mature, they kind of move throughout the facility—and so there’s ergonomic stresses of moving the plants around. 

It’s also the processing aspect. You’re cultivating and then you’re harvesting, actually having to take the leaf off of the plant. A lot of times, that’s a lot of very fine hand movement to cut those leaves off. There’s mechanical ways of doing that, where the ergonomic stressors wouldn’t be nearly as strong. Especially when you’re looking at hand trimming, when you have the final, the bud or the flower, there’s a lot of really small fine movements with a hand to go around the flower and make it presentable for the consumer, especially on the recreational side of things. That’s where you see just a lot of those ergonomic stressors coming into play.

Psychosocial, there’s the stress of working in this environment where there’s still connotations with working in the cannabis industry. There’s also the all cash aspect, security, because a lot of these facilities can’t use banks, so they have large volumes of cash on hand. So, there’s just different psychosocial stressors that are probably present in this industry that we might not see in others. We wanted to at least give an homage to that, even though we didn’t study it as much.

Cannabis Wire: Based on your research, how is the cannabis industry responding to or preparing for these workplace hazards?

James Couch: I can only speak from my experiences with the facilities that I worked with. 

But, you know, they were very inquisitive, asked great questions, asked in a lot of cases the right questions that they should be asking. So, they were very knowledgeable. There’s a lot of unknowns. And so there’s a lot of the industry asking good questions about how to figure out what these potential occupational safety and health hazards are. And, we’re kind of developing the guidance on the front end, as opposed to having 20 or 30 years of experience or history to draw from to craft those recommendations. 

We’re really trying to be more on the front edge of this industry, as opposed to waiting that 20 to 30 years to do the research. We’re trying to look at it very early in the industry, and hopefully make those recommendations that get the buy-in from the industry to approach these things early on, so that we don’t have issues 20, 30 years down the line. 

Cannabis Wire: You write that the trend is clear that there’s a need for occupational safety and health information for an emerging industry. I haven’t seen a big educational push from NIOSH. What are you able to do as far as putting out guidelines? Are you able to do so, considering federal law? 

James Couch: That’s a very valid point. We have heavily relied on the HHE reports themselves to be more the layman’s terms of the research. We try to write them in such a way that they’re more understandable for all groups of people. But, you’re exactly right. There really does need to be more products that kind of talk more to the overarching aspects from those recommendations. 

You hit on something, that we are a little bit constrained from being a federal government agency, and those issues with that. But there are also states out there that are doing some really good work on putting guidance out, such as Colorado, Washington and California. But, I would agree that we don’t have an overarching communication product out there currently that kind of ties all this together. 

More Q&A: Here’s What the CDC Has Learned About Cannabis Workplace Hazards