Hi
I had the same concerns as you when I started.
The way I see it, there are certain number of 'attitudes' to the safety of inhaling vapour. What I have discovered over the last 2 years is that the only people who we/you can trust are the scientists who have
nothing to gain from being either anti or pro e-cigarettes. This means anybody connected to either the tobacco or pharmaceutical money train are NOT to be trusted. It sounds a bit paranoid, but I believe it to be true. Also, there are people in public health who are forced to maintain a pessimistic approach because;
no.1) they want us all to quit smoking by not vaping and
no.2) as it's early days for vaping, they don't want to recommend it, just in case something about them works out to be a little harmful, even if that's a lot less harmful than smoking tobacco.
So, I listen to the people who understand the concept of harm reduction and that some people will never quit nicotine. ALL these scientists seem extremely optimistic about the possible dangers of vaping, not because vaping is 100% SAFE, but because it so far seems remarkably SAFER then smoking.
The top two UK scientists without an axe to grind are both convinced vaping is way, way safer than smoking and may actually carry almost no risk at all.
Look into the details at CASAA or google people like Professor Peter Hajek.
https://www.youtube.com/watch?v=SVS0_BGHHjM