There are health risks linked to the chemicals found in vaping products. The safety of inhaling these chemicals is still under investigation, but there have been several cases of a severe vaping-related lung illness in Canada and over 2000 in the US. The illness is similar to a chemical burn in the lungs.
Tetrahydrocannabinol (THC), the psychoactive ingredient in cannabis, has been linked to the majority of cases of vaping-related lung illness by the US Centre for Disease Control. THC/ cannabis use is associated with a range of negative health effects and is still being investigated. Most recently, vitamin E acetate was identified as strongly linked to the THC-related vaping illness. While safe for use on the skin or to ingest as a supplement, vitamin E acetate can interfere with normal lung function when it is inhaled.
Additionally, e-cigarettes contain some chemicals both suspected and known to cause cancer as well as particulate matter that can penetrate deep into the lungs and cause cardiovascular damage. The process of heating the e-liquid can produce additional chemicals whose health effects are still under investigation.