Important info for anyone concerned about diacetyl and substitutes:
The legal (OSHA) definition of diacetyl-free allows up to 1%: " “Diacetyl-containing” means containing diacetyl at a concentration of 1% or more by weight."
The legal definition for Acetoin-free allows up to 1%.
The legal definition for Acetylpropionyl-free allows up to 1%
Flavoring could contain just under the legal limit for each ingredient and still be legally described "diacetyl, acetoin, acetylpropionly free" - despite containing nearly 3% diketones.
Other diketones exist; I've never been able to determine if any flavoring companies currently use any besides the 3 listed above.
Only 2 flavoring manufacturers (that I know of) have ever released the results of lab testing: Flavour Art and The Flavor Apprentice.
FlavorArt's e-cig line contains NO diketones and is the only company to test cytotoxicity of actual vapor from their flavorings:
http://clearstream.flavourart.it/site/?p=181&lang=en
The Flavor Apprentice has been listing (<.5%, 1-10%) percentage of acetoin and/or acetylpropionyl for each flavoring that contains any:
http://shop.perfumersapprentice.com/specsheetlist.aspx
Decision of what we vape is our individual choice, always. I'm just putting this info here for those who are concerned. Only FA and TFA release actual lab results. They have chosen to give vapers this info. Other companies can legally claim they have 0%, yet have nearly 3% total diketones (perhaps more with creative chemists who use other diketones).
At least 1 Flavor West flavoring that was claimed "diacetyl-free" was proven by an independent lab to be far beyond legal limits. So far as I know, NO penalty has resulted. (thus providing an example of what happened to one company who outright misrepresented their ingredients to vapers)