A French consumer magazine reported this week that e-cigarettes may contain "significant amounts of carcinogenic molecules."
According to the "60 Million Consumers" monthly magazine, a study found that three times out of 10, the level of formaldehyde produced in e-cigarettes comes close to the amount in conventional cigarettes.
The study also claims to have found that certain models are missing safety caps and could contain liquid nicotine lethal to children.
E-cigarettes use heat to vaporize liquid nicotine but contain no tobacco. The FDA is considering regulations that would ban the online sales of e-cigarettes.