[jyl]

The device uses heat to vaporize liquid chemicals, primarily synthetic (!) nicotine and polyprene glycol (?), but also artificial flavours and who knows what else - remember, they are made in China, where even baby formula can be poisonous - into a vapor that you inhale into your lungs.

No one knows if this is safe. We know it doesn't cause discernible health effects right away, and that is all we know. Interestingly, that is about what we knew about cigarettes back in WW2 or whenever they became popular (weren't they supplied free to US GIs?)

No one has done any real long term testing in animals or humans. The manufacturers don't really care to. There are zero standards for these things or for the liquid being vaporized and inhaled.

So, the users are doing the long term health testing.

I think they are probably safer than cigarettes. But I'd still get off them as quickly as you can. I think it is perfectly possible that, in a decade's time, people will be sick from some effect of these that we don't know about today.

Anyway, there is a chance that FDA will ban them soon. Canada already has, as have several other countries.