Well folks here we have it. Before I make my comments the article source is here.
Harvard published a article a couple days ago about the chemical flavourings in e-cig juice which it has linked to lung disease. As the article mentions the focus had been on nicotine which was overshadowed by the other hazards of the device.
Me personally I have never been fond of them. People use them in my car (not going to mention any names but that person will know who he/she is when they read this) in public elevators, malls, on skytrain and well pretty much every where people can’t smoke now. As a former smoker its irritating because it drives me to want to pick up a cigarette and smoke again. And sometimes those damn things give me a headache. Anyways back to the article.
The chemical diacetyl which is the flavouring chemical is linked to cases of severe respiratory disease claimed in the first paragraph of the article. According to a wikipedia article on the chemical it is a avoidable risk for electronic cigarette liquid, can be taken out and eliminated with out limiting availability of flavours. In 2015 47 out of 51 tested liquids presented positive results to the chemical.
Further in the article the flavouring industry has warned workers about diacetyl because it is associated with bronchiolitis obliterans also know as popcorn lung because it appeared in workers who inhaled artificial butter flavour in microwave popcorn factories. OUCH, this makes me not want to each microwave popcorn again.
Essentially what they use to flavour the e-sigs is dangerous. Forget the nicotine aspect of the product.
Another article source is located here: http://ehp.niehs.nih.gov/15-10185./
Personally I think the products should be banned. They create a false sense of safety, are annoying as hell and clearly a potential danger to people. But of course thats my opinion.