Leonardo DiCaprio has been seen with one. So have Katherine Heigl and Lindsay Lohan.

The goodie isn’t a multimillion-dollar film contract but an electronic cigarette, or “e-cig.”

E-cigs have been on the market for nearly seven years, but their appearance in the Hollywood spotlight hints at a newfound popularity. “I’ve seen it around a lot and have been curious about it,” says Maxine Jean-Louis, 24, a case worker from Columbia Heights.

Also known as smokeless cigarettes, e-cigs contain no tobacco or tar. A battery-operated mechanism heats up flavored liquid that, when exhaled, emits an odorless and fast-fading vapor. The tip lights up, and depending on the choice of cartridge, the smoker can ingest nicotine.

It is too soon to tell whether e-cigs are safe or just the lesser of two evils. Non-industry­sponsored studies are scarce, so it’s unknown whether a relatively unstudied nicotine device, containing a variety of chemicals whose effects remain to be seen, can be considered “safe.”

“The product has not been well-known because of the stigma directed toward regular cigarettes,” says Jason Healy, chief executive of Blu Cigs, one of the leading electronic cigarette brands.

On April 25, the Food and Drug Administration decided to regulate e-cigs as it does tobacco products, rather than under the strict regulations reserved for medical products — a victory for the e-cig industry, which has come under fire from anti-smoking forces over the addictive effects of nicotine and fear that nonsmoking kids will begin “vaping.”

Jean-Louis, a smoker for five years, views e-cigs primarily as cessation devices, which could be a reason celebrities have taken to vaping.

“We aim at that older, more mature market,” Healy says. “E-cigs are not as attractive to younger people because they’re not banned. There’s no rebellious aspect to them. But once you get older and start caring about what you put in your body, it changes.”

Still, with some celebrities using the product, the demand for e-cigs could rise. Blu Cigs have tips that light up blue so they can be recognized by nonsmokers. “When I made the tip blue, everything went from, ‘Hey, you can’t smoke here!’ to ‘What the hell is that?’ ” Healy says. “It went from anger to curiosity.”

Also, as cigarette prices rise, e-cigs might present a cost-effective option for smokers. Though the price of e-cig starter kits can be considered high (on average between $40 and $200), refilling cartridges is comparably cheap, as they last longer than regular cigarettes.

Now Blu Cigs has decided to push the possibilities further by developing a Smart Pack, slated for release this month. The product will capitalize on the popularity of social networking, linking Blu users and indicating nearby Blu retailers and locations that allow vaping.

“Almost by accident, the stigma directed at smokers forced them into a community,” Healy says. “Twenty percent of Americans smoke, and most of our sales are by referral. So that’s a pretty significant number that we’ve barely scratched.”

Chammas is a freelance writer.