Nirk moved from nic gum to vaping so it is unlikely it is 'toxins'. I don't know where people are getting vaping is 100% safe, we just don't know that and will not for 10-20 years. What we do know is that is is much better than smoking. At least that is what the doctors and professors that I've read are saying.
Mmm I think that if you are vaping through a large amount of liquid that high VG liquid may be a bad idea. I do not have any evidence for this other than my experience and what I have read about VG. Firstly it is oily and coats your insides, secondly it can produce some nasty things when burnt at very high temps, although this probably not apply at the temps in vaping.
Since smoking high VG it has made my lungs hurt and messed up my throat, also because it is not antibacterial like PG and it coats your tongue, this makes it more likely for you to catch a virus or similar... Which is what seems to have happened to me... Usually I get ill maybe once every 5 years.... Hardly at all.... Think I will stick to 70/30 or similar from now on and keep to <3ml a day.