The 'popcorn' issue is pretty much linked to one artificial flavor... Diacetyl... anything that involves a buttery taste. Often found in microwave popcorn, hence popcorn lung.
Custards, a popular group of vape flavors, was the main source of it.
The catch?
Diacetyl is also a byproduct of cigarette smoking.
The risk was not considered to be noteworthy among cigarette smokers and food workers who had higher exposure to the chemical diacetyl...
> Further, because smoking has not been shown to be a risk factor for bronchiolitis obliterans, our findings are inconsistent with claims that diacetyl and/or 2,3-pentanedione exposure are risk factors for this disease.
