Nobody knew at the beginning. We don't know if the Chinese knew about the USA popcorn factory incident that led to the bronchi obliterans in some ppl. In the early days of the formation of ECF, some of the original Veterans began discussing it, fortunately. There have been many discussions of diacetyl since then, but it just keeps getting shoved back in the threads. With the last BIG diacetyl discussion, there were too many fights on the thread, and it kept getting locked on us. A few ppl were banned and a few just left ECF over it. At the last, ppl just tired of posting on it because of the bickering of the two distinct groups: the anti-diacetyl and the pro-diacetyl.
Since then, hundreds of ppl began hounding the suppliers about diacetyl, and luckily since then, suppliers have appeased their customers by making wiser choices on the juices they supplied and that they compounded themselves. Things are much better.

If you ever get bored, here is the diacetyl thread below that had so much bickering on it.
http://www.e-cigarette-forum.com/fo...ove-diacetyl-their-e-liquids.html#post2008208
One more thing ..... suppliers do not have to say where their ingredients originate - that is considered proprietary information. All the FDA requires are the ingredients on foodstuffs. However, eLiquid is not regulated yet, so technically, nothing is required - as best I understand it.
Our little Shiloh? Aww, she's always sweet. I know that b/c I'm the mouse in her pocket.