Vaporable Cannabis Concentrates' Potential Health Risks

As more U.S. states and countries legalize medical and recreational marijuana, consumers are increasingly turning to new types of products that avoid toxic smoke inhalation. Researchers at Berkeley Lab who previously identified potentially harmful emissions from electronic cigarettes are now identifying the potential health risks of vaping cannabis.

When a person vapes marijuana, they are inhaling vaporizable cannabis concentrate (VCC), which is a concentrated liquid or a waxy solid form of cannabis also commonly referred to as “extracts” or “hash oils.” The concentrated liquid is usually heated into an aerosol by a battery-operated electronic device, while waxy concentrates can be aerosolized by direct application onto a heated surface (known as “dabbing”).

In a new Berkeley Lab study recently published in the journal Environmental Science & Technology, researchers examined emissions associated with heating only the non-cannabinoid constituents of VCC, which are extracted from the cannabis plant alongside the psychoactive constituents but do not cause drug-like effects on the body. These non-cannabinoid compounds are a major part of VCC formulations and include terpenoids, flavonoids, and lignins – all commonly found in plants and potentially harmful when inhaled.

The research team, led by Berkeley Lab scientist Hugo Destaillats, heated and aerosolized mixtures of those compounds to simulate cannabis vaping and dabbing. They observed the formation of a large number of ultrafine particles that were released into a room-sized chamber and remained airborne for at least three hours.

“Our results suggest that high molecular weight compounds such as lignins, flavonoids, and triterpenes enhance the formation and accumulation of ultrafine particles in the air, which can then serve as carriers of substances that normally are not found in the air – otherwise known as nonvolatile and semivolatile species,” said Berkeley Lab scientist and co-author Xiaochen Tang. “These substances can then be breathed into a person’s lungs and found in the indoor environment.”

The research team also quantified 11 degradation byproducts as a result of heating the mixtures, including acrolein and methacrolein, which are highly irritating to eyes and the respiratory system. According to the study, these compounds are predicted to reach levels that may exceed reference exposure levels recommended by California.

“The bottom line is that emissions from heated cannabis concentrates are not innocuous,” said Destaillats. “Vaping and dabbing can be a source of harmful chemical exposure, and more research is needed to determine the full extent of the risk.”

The study was funded by the University of California Tobacco Related Diseases Research Program (UC-TRDRP).