Laws have been introduced in New York and Chicago making it illegal to use an electronic cigarette in indoor public places, such as restaurants and bars.

Supporters of the technology believe that vaping can wean people off traditional cigarettes.

The science behind the claim is sketchy to date.

The former NYC Health Commissioner Thomas Farley said: “We need to protect people until we understand vaping better and figure out how to use them only in ways that may help people.”

Those who embrace vaping say lumping users with smokers may well turn people back to the demon weed.

Peter Denholtz, CEO of Henley Vaporium, an outlet for the technology, questioned the logic: “Now if you want to stop smoking and use vaping products you have to go out and sit with the smokers and be around exactly what you are trying to get away from?”

It is now illegal to sell vaping products to those under-18 and retailers are required to keep devices behind the counter.