Electronic cigarettes are often billed as a safe way for smokers to try to kick their habit. But it’s not just smokers who are getting their fix this way. According to a survey published by the Centers for Disease Control and Prevention, 1 in 5 middle school students who’ve tried one say they’ve never smoked a “real” cigarette. And between 2011 and 2012, e-cigarettes doubled in popularity among middle and high school students.

At a middle school in the San Francisco Bay Area, Viviana Turincio, an 8th grader, recently noticed some kids smoking in class — or at least, that’s what it looked like.

“There was a group at the table,” she remembers. “And they were just smoking on the vape pen, and the teacher was right there — and the teacher didn’t even notice.”

That’s because her classmates were smoking an electronic cigarette, sometimes called a “vape pen.” It’s a hand-held, battery-powered device that vaporizes a liquid that is often infused with nicotine. You inhale the vapor through a mouthpiece, and exhale what looks like smoke. In this case the smoke smelled like candy.

“My favorite flavor is gummy bears because it tastes really good,” Viviana says.

Vapor liquids come in various flavors, but teens often prefer dessert-inspired ones, which are more appealing than the smell and taste of burning tobacco. Marleny Samayoa, also in the 8th grade, thinks traditional cigarettes taste too bitter. “It has kind of a weird taste to it, like coffee without sugar,” she says.

E-cigarettes are easier for kids to buy than regular cigarettes. There’s no federal age restriction for how old you have to be to buy them. But some states, including California, prohibit the sale to minors. That’s why middle-schoolers turn to online sites like eBay, where independent sellers don’t necessarily ask for your age.

“A lot of kids are getting them online,” Marleny explains. “And they’re just introducing it to a lot of other kids, and it just keeps going from there.”

She has noticed the growing popularity of e-cigs on social media sites like Instagram. Look up #Vapelife and the pictures are endless. “I take pictures and do tricks, like blowing O’s,” Marleny says, “blowing them on flat surfaces and making tornadoes.”

Swirling clouds of vapor are touching down in theaters, restaurants and malls, while health professionals are trying to catch up with this new fad.

John Hartigan, proprietor of Vapeology LA, a store selling electronic cigarettes and related items, takes a puff from an electronic cigarette in Los Angeles.

Dr. Cathy McDonald runs a center for tobacco dependence, treatment and cessation for Alameda County, Calif. She admits that, “right now we don’t have as much information as we would like.” What scientists do know, she says, is that “10 minutes of smoking an e-cigarette — for a person who has never smoked a cigarette — does cause a noticeable increase in airway resistance in the lungs.”

But, McDonald concedes, “It’s probably better than smoke. And I say that because smoking a cigarette is 4,000 chemicals — 400 are poison, 40 cause cancer.”

Researchers haven’t had the time to do long-term studies comparing traditional cigarettes to electronic ones. But at least among my friends, the smokers who have made the switch say they’ve noticed a positive change. My boyfriend, Gray Keuankaew, is one of them.

“Within the two months that I’ve been vaping, my body feels a little bit more healthy,” he tells me. “So if there’s going to be any type of positive benefit, then I’m definitely going to stick to it.”

I’m glad it’s now easier for him to run, but he hasn’t outrun his nicotine addiction. E-cigarettes still contain nicotine — you choose what amount you want. The Tobacco Vapor Electronic Cigarette Association estimates that e-cigarette sales will surpass $2.5 billion this year.

“Our target customer base is those people who felt doomed to a life of smoking,” says Geoff Braithwaite, who owns Tasty Vapor, a company in Oakland that sells and distributes liquids for e-cigarettes. But he admits that adults aren’t the only ones who may be jumping on this new trend.

“There’s going to be that novelty around it — it’s a brand new thing, it’s an electronic device,” he says. “That kind of stuff will always appeal to kids; it would have appealed to me.”

Anti-smoking campaigns spent decades and a lot of money to make smoking less appealing to youth — and that helped cut teen smoking by 45 percent. But cheap prices for brightly colored e-cigs, sweet flavors, and the ability to vape anywhere are putting nicotine back on the kids’ menu. The Food and Drug Administration has said it plans to regulate e-cigarettes, but so far the agency hasn’t issued any rules.