The Chief Medical Examiner for the Michigan Department of Community Health, Mathew Davis says e-cigarettes should be classified as tobacco products in the state. If that's approved it would then be illegal to sell them to minors.

They are becoming increasingly popular with sales nationwide topping $1 billion last year.

Electronic Cigarette - Photo by Getty Images

E-cigarettes contain a liquid that has nicotine in it. The liquid itself does not smoke but the device vaporizes the liquid instead. While they have been called safer than regular cigarettes health officials say more study has to be done to determine if they really are. Davis says we know very little about their health risks.