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How Should the Cannabis Industry Regulate Heavy Metal Testing? A Q&A With Rob Thomas

By Leo Bear-McGuinness

Published: Jun 15, 2021    Last Updated: Jun 17, 2021
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Two years ago, Rob Thomas was unknown and unfamiliar to the US legal cannabis industry. Now, he’s considered one of the leading voices and experts on heavy metal testing in cannabis products. So what happened?

Ahead of his upcoming ASTM-sponsored workshop on measuring heavy metals in cannabis and hemp products, Analytical Cannabis caught up with Thomas to find out how he became the cannabis industry’s heavy metal guru and just what attendees can expect from his upcoming workshop.

Leo Bear-McGuinness (LBM): So, how did you come to be hosting this event?

Rob Thomas (RT): Having worked at PerkinElmer, the instrumentation company, for 25 years, I took early retirement in the early 2000s and went into the world of freelance science writing.

But about two years ago, I had just finished a textbook on measuring elemental impurities in pharmaceuticals. And it was suggested that I take a look at the cannabis industry, because they were in need of guidance with regards to heavy metals.

So, I came to it then, not knowing anything about the cannabis industry. I talked to a lot of people, got a lot of advice, discovered that the industry was a little naive and, they weren’t really doing a good job of regulating a full suite of elemental contaminants . So I just knew that, with my 45 years of experience in the field of trace element analysis, I felt that I could help. And [I] decided that a textbook would be very useful.

The book got published in October and that’s when I started getting a lot of visibility. And as a result, ASTM contacted me and asked me to help them. So I came on board initially to review an ICP-MS method that they were working on for cannabis and hemp.

I thought that it would be worth investigating the possibility of doing a webinar on heavy metals, not really knowing where it would go. So initially, I just thought an hour-long webinar would be very useful, sponsored by ASTM. However, when it got developed, the momentum grew. I got a lot of buy-in from the ASTM senior management. And when I eventually suggested a one-day workshop, they said, ‘Yeah, go ahead and get some speakers.’ But when I went out to my network, I was overwhelmed with the response. It eventually turned out to be a three-day workshop. It got much, much bigger than I ever imagined.

I was not known two years ago with the cannabis industry. And I think it’s fair to say that I’ve now been given the tag of the heavy metal guru in the industry, which is great, and very complementary. 

So I’m driving this workshop, but  a couple of my ASTM colleagues helped me  put the workshop together with 23 high-caliber talks, which is coming to fruition at the end of June – very, very exciting. I’m convinced that it’s going to grab the attention of the industry and hopefully make [it] realize that it needs to do a more serious job of regulating heavy metals, particularly with federal oversight around the corner, whatever around the corner means. It cannot go on being regulated by states for very much longer, because there’s a lot of stuff going on which unfortunately is leading to unsafe products. And as a result, there have been numerous product recalls out over the past 6-to-12 months for heavy metals exceeding state-based limits.

LBM: Well, congrats on your position as heavy metal guru.

RT: Yeah, it feels it feels kind of surreal. But it’s getting me a lot of visibility and my workload has increased exponentially. This is my second career. And, if you like, my second career has probably given more satisfaction than my first career. I feel as if it’s a meaningful contribution to improve the safety of cannabis products.

LBM: And since you’ve assumed this role, over the past two years, how much progress have you seen in heavy metal regulations and testing in cannabis products?

RT: Very little. The vast majority [of US states] just regulate the big four [cadmium, arsenic, lead, mercury]. There are a couple of states which throw in additional elements, like my state of Maryland, which also regulates selenium, silver, barium, and chromium, while New York includes nickel, chromium, antimony, zinc, and copper. But there’s no momentum to increase that list. The only side of it which is gaining attention is regulating cannabis vaping devices, which is completely different because the vaping liquids are corroding internal metallic components, which has nothing to do with what elemental contaminants are actually in the cannabis product being vaped.

LBM: That’s the other half the problem, isn’t it? Heavy metals can be absorbed from the soil when the cannabis plant is growing, but they can also be drawn from the components of vaping devices.

RT: Yeah, the issues are very different. We shouldn’t confuse them because I think that they will probably be treated separately by regulators, as they are doing in the state of Colorado, where regulators will be setting limits for elemental contaminants in the vaped aerosol and not just the cannabis concentrate.

LBM: It’s a lot to tackle, isn’t it?

RT: Yes, it’s so complicated. That’s why I believe the FDA does not want to get involved at the present moment, because it’s so fractured. And the industry, in reality, does not want strict regulations. It takes two-to-three days to develop a cannabis product and to put it on the marketplace. With a pharmaceutical, it takes two-to-three years. So work that out.

LBM: Coming back to the webinar, it’s great to hear that there has been such interest and support.

RT: Yeah, as I mentioned earlier on, this was just my request to do a one-hour webinar. I mean, ASTM International is the premier testing standards organization in the US and has a huge global presence. So, to be organizing a webinar, which was my original plan, it’s a big deal to me, and also to the industry for them to sponsor a three-day workshop. They don’t do that normally. So [I’m] very, very happy that they put their faith in me to do it. 

We believe that it could make a significant difference to the industry, how it moves forward and making realize that with federal oversight happening sometime in the near future they need to get their act together. They need to get a better handle of the entire manufacturing process. They don’t have that; it’s not like pharma. They [pharma] spent 25 years deciding what was important. So they have a really good handle of the entire manufacturing process. The cannabis industry has nowhere near this level of knowledge at the moment. And my hope is that it [the workshop] will help them realize that they need to get a better understanding of sources of elemental contaminants, from where to plant cannabis and hemp, to how the heavy metals are taken up and how they can be enhanced by nutrients and fertilizers and even the impact of the entire extraction and production process.

Workshop on Measurement of Elemental Contaminants in Cannabis/Hemp Consumer Products will take place virtually from Monday, June 28, to Wednesday, June 30. More information on the workshop’s schedule and on how to register can be found here.

Rob Thomas, principal of Scientific Solutions, was speaking to Leo Bear-McGuinness. Questions and responses have been edited for clarity.

Update: Rob Thomas' responses were expanded upon on June 17, 2021. The list of heavy metals required for testing in cannabis products in the state of New York was also corrected on June 23, 2021.

Leo Bear-McGuinness

Science Writer & Editor

Leo joined Analytical Cannabis in 2019. From research to regulations and analysis to agriculture, his writing covers all the need-to-know news for the cannabis industry. He holds a Bachelor's in Biology from Newcastle University and a Master's in Science Communication from the University of Edinburgh.


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