Cannabis is a heavily regulated industry. While every state may have different requirements for product testing, heavy metals and pathogens are a common concerns. And despite strict rules about heavy metals in cannabis, regulations over papers are scant at best, but a new study may have people questioning the safety of their smoking material.
The paper, published in the journal ACS Omega, focused on heavy metal levels in over 50 commercially available rolling papers and cones. A research team from Lake Superior State University in Michigan analyzed the products for over two dozen compounds, including the potentially hazardous arsenic, cadmium, mercury, and lead.
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A small number of samples had elevated levels of arsenic and lead. The levels of these metals did not exceed the recommended amounts, but paper authors are concerned about another element: copper.
Roughly one-quarter of the samples tested had copper levels higher than the recommended levels for “inhaled pharmaceuticals.” According to the CDC, health risks from exposure to copper include upper respiratory problems. Several papers also had concerning amounts of chromium and vanadium, both of which can be hazardous.
The elevated copper levels were mostly found in dyed papers, with the compound likely used in the color pigments. The study also pointed to materials in cone tips, some of which had metallic accents. Heavy metals in papers could come from uptake in the pulp used or the bleaching process, authors noted.
The researchers noted that while cannabis has been found to contain some heavy metals (the plant accumulates elements from soil, water, and other inputs), regulations around testing do not address the potential issues with papers and other smoking accessories.
“The results of this analysis suggest that several elements that are typically unregulated in consumer cannabis have the potential to contribute to significant exposures when smoked from certain rolling papers,” the authors wrote.
The study also noted that not all smokers put the maximum amount of bud in their papers, which could lead to even more risk.
“There is evidence that in common use, many consumers may fill papers to around half capacity, which would increase the mass of paper smoked per gram of cannabis consumed,” the analysis said.
The inquiry results mimic a similar study conducted by SC Labs in California, which found many papers containing heavy metals and pesticides. Some states do require finished goods like pre-rolls to be tested post-manufacturing, but many do not. SC Labs asserted the vast majority of pre-rolls on the California market are safe for consumption.
Smoking anything can be detrimental to your health, that’s no question. However, the imbalance between regulations on cannabis and the tools used to consume it is more than a little interesting. Bottom line: consumers need to understand the risks associated with what they put in their bodies in order to make an informed decision (dry herb vapes, anyone?).
