There is a good article at Vaping 360 on this titled:
Vitamin E Acetate Products Investigated in THC Oil Deaths
While I am saddened by what I consider an intrusion of drug dealers in to the vaping foray, it is important to put out the word that vaping cannabis is a wild frontier territory marred by illicit drug sales and can be very dangerous. And the young are particularly prone since they cannot acquire products legally.