So, after realizing that I am absolutely in love with CLS, I decided I should probably have a gander on the interwebs about diketones and their possible hazards. What I read is deeply disturbing. I had never heard anything about them until I started vaping. Obviously the main stories I read were about diacetyl and "popcorn lung". Some really disturbing stuff. But for a second I breathed a sigh of relief knowing I have never vaped diacetyl(although diacetyl is in analogs), and ALMOST no one uses it in ejuice anymore. But then I started reading about acetyl propionyl, and how it is being used as a replacement for diacetyl. Acetyl propionyl is actually a more complex diketone than diacetyl, which mean there is a good chance that it breaks down into diacetyl once in our bodies. I also read on several studies and experiments that have been done with acetyl propionyl, and the results are equally as disturbing as the ones done with diacetyl. In a 2 week inhalation study done on rats, acetyl propionyl caused proliferations of fibrous connective tissue in the walls of the airways. It also cause changes in gene expression in the brain.....some really scary stuff, and as much as I love CLS, I think I personally may have to stop vaping anything that contains diketones.....I started to vaping to potentially clean up my health, and much of what I have read seems that some of these flavorings are worse than cigs. This is a sad day for me knowing I probably wont be ordering anymore CLS, but on the bright side, H1N1 is freaking amazing!!!