The comparison to Tylenol spiking is perfectly apt if you consider the whole category of toxic adulterants as the noxious agent. (I know that THC/vit-E wasn't the totality of cases. You can only go so far without drowning in pedantry.) Moreover, it seems to have been a very North American phenomenon. Europe is quite vape-mad and you can count the number of vape-related lung injuries on one hand.