News People are vaping a deadly substance along with THC. So why isn’t vitamin E acetate illegal? November 15, 2019Jayne O'Donnell and David Robinson, USA TODAY NETWORKComments Off on People are vaping a deadly substance along with THC. So why isn’t vitamin E acetate illegal? Vitamin E acetate is sometimes used as to dilute THC oil in vape cartridges to make it go further. It can be deadly, but it's not banned everywhere.