It's not nicotine users specifically at risk here, because unflavored nicotine liquids are available, as well as flavored zero-nicotine liquids. Flavorings seem

It's not nicotine users specifically at risk here, because unflavored nicotine liquids are available, as well as flavored zero-nicotine liquids. Flavorings seem like an unnecessary risk to me -- the dangers of diacetyl have been known for several years so it doesn't surprise me that other flavorings can also damage lungs. None of them have anywhere close to the level of safety research as the nicotine or the carrier liquids (propylene glycol or glycerol). Even before this research the risk:benefit ratio for flavorings looked very dubious.