I vape essential oils fairly frequently without any issues. The trick is getting really pure essential oils, and diluting them a lot.
A single drop of peppermint EO is plenty to flavor 15 ml of juice.
You really don't want to vape any oils at all, but essential oils are really more volatile aromatic compounds than traditional oils. If you leave a few drops of essential oil on the counter overnight it pretty much evaporates- not true with something like canola oil.
They're meant to inhale in responsible, small quantities- that's what aromatherapy is. I'm relatively certain inhaling 3-4 drops of peppermint essential oil every week isn't going to kill me any faster than analogs.