I agree, if they dont list the ingredients and I were worried, then I would not
buy it.
Hangsen I believe does list their ingredients and have been supplying to the US for years. In fact now that I am making my own tobaccos I have bought and use Hangsen
tobacco flavors, I love em, and I know they sell ready made liquids using their flavorings.
If its being made in other countries or even in the US and they list something like this:
PGand or VG
water if used
Flavorings
I might be a bit suspect about what the "flavorings" consist of. Some companies list the flavorings ingredients or have a list of ingredients in their flavorings. Some will say "may contain .... " in that flavoring so those with sensitivities can decide.
I dont know if they have to specifically list propylene glycol and vegetable gycerol , there are variants of both and glycol and glycerin and glyceroids etc... ( im not a chemistry expert ) but those chains of molecules change extremely.
PG and VG are used in countless products we use on, in our bodies, they are consumed in almost everything we buy, spray, inhale.
Its comes down to the flavorings. Some use organic, natural etc. Again there are hundreds of natural, organic and botanical ingredients that are deadly.
Alcohol is another ingredient that has been debated on , some say its great, as it add that throat hit, some flavorings are extracted using grain alcohol etc.
Its all dependent on what you need, what you think you need and trust.