Interesting, from what I read Essential Oils are also created through water-and-steam distillation process which seems a bit different but sorta the same, there seems to be a lot of controversy on what is and isn't safe to inhale, have you checked out the thread about Diacetyl on the E-Cig forum, apparently it can also come from natural sources, have you tested for this?
Thanks for checking in here, I like to hear from the sources.
I am familiar with that thread, and it is frequently used as a reference for the anti-organic folks.
There is diacetyl in every natural/organic butter flavor. The caramel flavor is extracted from carmelized butter, therefore it is safe to assume that there is some amount of it in there.
That said, every confirmed case of popcorn lung (so far, knock on wood) was a result of massive, massive dose of artificial butter flavor. But on the other hand, I would be hesitant to mix some juice with 5% organic butterscotch and make it my all day vape.
In the end, vapers are their own test-monkeys. My philosophy is that they deserve to know what it is they're testing. People should know what they're vaping so they can make their own, informed, decisions. I had mixed feelings even using the caramel flavor, but in the end what is important is letting people decide for themselves.
Side note: my flavors and essential oils (check the vanilla chai and toka-cola, a number are used in them) come from Medicine Flower. The tobacco is a co2 extract and is listed under perfumes. The EO, perfume, and flavors are all food-grade, just a difference in marketing.