Propylene---*not* "polyethylene"--- glycol. Got it!
All those chemical-words are like chinese algebra to me.
So it's vegetable glycerine and propylene glycol. There's a lot of carbon in those molecules, no?
If you've seen hospital patients getting a "breathing treatment" It's Propylene Gycol that creates the vapor to carry medication into the lungs. It does the same with nicotine and flavors for vapers. If you want to be concerned about components of ecig vapor the worst offender could be flavors if you don't check them out for Diacetyl (buttered popcorn flavor) and several other ingredients you don't want in your lungs, but nicotine, PG, and VG aren't the chief offenders.