I have tried to get an answer from Green Smoke as to whether or not the flavors used in their e-cigs contain any diacetyl or acetyl propionyl. I e-mailed the question to their so-called award-winning customer service department and never received a response. I posted the question on Green Smoke's Facebook page and got the reply that they do not add Diacetyl to any of their products. They did not mention Propionyl. When I questioned that, the response I got was that "that's all the information I've been given". Just because Green Smoke doesn't add something to their products doesn't mean it's not in products they purchase, such as flavorings. The fact that they seem unwilling to disclose whether or not their flavorings contain diacetyl or acetyl propionyl sends up a big red flag as to the health risks of their cartridges.