Other teams have found other potentially cancer-causing chemicals in e-cigarette vapor, including diacetyl, the chemical blamed for causing "Popcorn lung" in workers at microwave popcorn packaging plants. The list of compounds included acrylonitrile, acrolein, propylene oxide, acrylamide and crotonaldehyde.
He explained that proplyene glycol and glycerin, which are used to keep the products smoked in e-cigarettes in liquid form, are safe at room temperature.
"Electronic cigarettes generate nicotine in the vapor".
They said teenagers who try vaping are poisoning themselves with numerous same chemicals that make traditional cigarettes so deadly.
The relatively small study tested 67 teenagers who reported vaping, compared to 16 teens who both vape and smoke traditional tobacco cigarettes.
According to researchers this study establishes the presence of harmful cancer causing chemicals in e-cigarette users.
"Teenagers need to be warned that the vapor produced by e-cigarettes is not harmless water vapor, but actually contains some of the same toxic chemicals found in smoke from traditional cigarettes", said lead author Mark L. Rubinstein, MD, a professor of pediatrics at UCSF.
The study cautioned that e-cigarettes are often promoted as a safer, healthier alternative to traditional tobacco smoking. Teens, even middle schoolers, have taken up e-cigarettes as well. He said they are sold to adults as a means to "harm reduction" and adolescents should not be using these at all. For the first time they are also found among teenagers who vape, they write.
But he added: "When they're heated to the high temperatures required for vapourisation, they can produce toxic substances that are potentially carcinogenic".
More than half of the e-cigarette participants indicated using fruit- or candy-flavored products, which left significant amounts of the compound acrylonitrile, which is used widely in the manufacturing of plastics, adhesives and synthetic rubber.
Teens who used only e-cigarettes, especially particularly sweet or flavored juices, had much higher levels of chemicals than those who don't use either tobacco product. This trending, however, has been proved to turn e-cigs teens vapers into regular cigarettes smokers.