More than a million people use e cigarettes to stop smoking and there's calls for them to be sold in hospitals but is vaping safe? E cigarette May Help to Quit Smoking With Minimal Side Effects, Suggest Studies E cigarettes: Facts, stats and regulations FMD Study shows dual use of cigarettes and vapes can reduce risks of smoking and help smokers quit Queen Mary University of London Different types of e cigarettes from the first to fourth generation. Download Scientific Diagram File:History of e cigarette.jpg Wikimedia Commons