>>> after an extensive review tonight, the fda says menthol cigarettes likely pose a greater health risk than regular cigarettes. menthol flavoring is more likely to attract younger smokers. and menthol smokers traditionally have a harder time quitting. as more smokers try to quit. in addition to all the products out there, more are turning to electronic cigarettes. so-called e cigarettes are surging in popularity, along with questions about what's in them. our report tonight from kate snow .

>> reporter: the marlboro man hasn't been on tv since the '70s, but now there's this guy.

>> it's time we take our freedom back. come on, guys. rise from the ashes .

>> reporter: the number of people using e cigarettes doubled from 2010 to 2011 , with celebrities leading the way.

>> it's got a bejewelled bottom.

>> it delivers the same amount of nicotine, but the smoke is water vapor .

>> reporter: they call it vaping. the advanced models you fill with a flavor and nicotine, to disposables with led tips.

>> i can't even smell it.

>> reporter: newton lost his mom, a lifelong smoker to cancer and sees his products as a life saving alternative.

>> there are 4,000 chemicals in tobacco, we end up with 12 or more, depending on the flavor.

>> reporter: flavors like watermelon and chocolate, which critics say attract younger people. there's even a section on the menu called like a kid in a candy store . e cigarettes are not yet regulated in the u.s. and the fda warns consumers have no way of knowing whether they're safe.

>> the marketing is way out ahead of where the silence is.

>> reporter: without regulation, it's hard for users to know exactly what's in e cigarettes.

>> they think, well, this is just nicotine and harmless water vapor , what's the big deal ?

>> reporter: we know that nicotine is a highly addictive drug, we don't know what the combination of chemicals in the e cigarettes does to the body.

>> reporter: but in ft. worth where employees are allowed to vap on the job, they're healthier.

>> i tried lots of ways to quit. until i tried this. and now i don't smoke any more.

>> reporter: chris putnam says he's more productive too.

>> it takes on average, 10 minutes to smoke a cigarette. that's an hour of time i'm pretty much not working.

>> reporter: with sales expected to top $1 billion this year, it's no surprise all three big tobacco companies are now investing in e cigarettes. looking to replenish their shrinking customer base by jumping on a growing