This is very interesting (to me anyway). I have quoted a bit from the paper below. I think whoever wrote the paper must've been a very fast typer, because I had to read it slowly and more than once before it began to sink into my thick head.
http://publichealth.drexel.edu/~/media/Files/publichealth/ms08.ashx
Here is a link to the paper (PDF) itself...there is no evidence that vaping produces inhalable exposures to contaminants of the aerosol that would warrant health concerns by the standards that are used to ensure safety of workplaces.
http://publichealth.drexel.edu/~/media/Files/publichealth/ms08.ashx