I just discovered http://www.ecigarette-research.com/web/index.php/research
He has quite a few peer reviewed studies regarding ecigs and ejuice. Recently he tested 160 juices from major vendors for Diacetyl and other diketones. I believe this study is still waiting to be reviewed before it will be published. BOLO.
I was shocked to hear that they found diketones in so many liquids. It really makes me re-think my perception of what is safe to vape or not. I wish that they would have tested flavors and not just eliquid. I want to know which flavors to avoid when making juice for myself and others. I'm thinking about contacting AEMSA to see if they have started to test flavorings for diketones.
Update I just sent an email to AEMSA. I will post their response if any.