Cannabinoid-containing liquids can produce the highly toxic gas ketene, with the vaporization of CBD acetate being particularly risky. In late 2019, approximately 3,000 e-cigarette users in the U.S. were treated for lung damage, with subsequent analyses revealing that the partially fatal health damage was caused by vitamin E acetate added to some liquids as a substitute for cannabis. However, when vitamin E acetate is heated, it produces highly toxic ketene. A study by Portland State University (PSU) now shows that the problem has reoccurred, with the legalization of cannabis in many U.S. states leading to an increase in stimulants with similar effects to tetrahydrocannabinol (THC) being offered. This includes THC acetate, which is not yet regulated by the Food and Drug Administration (FDA) and can therefore be sold freely.
The researchers analyzed whether the toxic substance ketene is also formed when THC acetate is vaporized, as the chemical structure of THC acetate and vitamin E acetate is very similar. The study focused on delta-8-THC acetate, an isomer of natural delta-9-THC that is synthetically produced, as well as the acetate forms of cannabinol (CBN) and cannabidiol (CBD). The experiments were conducted using commercially available e-cigarettes to vaporize the liquids, and an alternative inhalation method known as “dabbing” was also examined. The measurements showed that toxic ketene is produced when THC, CBN, and CBD acetate are dabbed or vaporized in e-cigarettes, with the highest concentration of the toxin being found in CBD acetate.
The concern is that consumers with a lung volume of five liters inhale approximately 78 micrograms of ketene with just one deep breath, while authorities in the U.S. have defined a limit of 43 micrograms of the toxin as an acute danger to life or health. The study’s lead author, Kaelas Munger, explains that the measurements should be interpreted with caution because most consumers take multiple breaths. However, the study highlights the need for further research to determine the risks associated with prolonged exposure to ketene. Without such research, people could be exposed to the toxic substance without any evidence of its harmful effects.
