E-cigarette vapor, even when nicotine-free, found to damage lung cells

…nicotine-free e-cig solutions were also found to include lung-harming substances, such as acrolein. This substance, which is present in both e-cig solution and vapor, has been shown to damage the lungs by attacking the molecules that hold endothelial cells together.  [The same cells that are attacked by nicotine itself.]

http://www.sciencedaily.com/releases/2015/05/150526084955.htm