In just a few years, "vaping" - e-cigarettes produce vapor, not smoke - has upended the market.
A stigmatized habit is suddenly cool again. A burning stick has become a high-tech gadget (one product vibrates when it senses another nearby, a sure conversation-starter). Falling cigarette sales are balanced by big growth in electronics.
The most deadly behavior in the United States might morph into a lifesaver. Or a product with an unknown safety profile might lure more smokers. The e-cig has divided a public health community whose reliance on carefully collected scientific evidence is no match for a fast-moving new technology backed by some of the world's slickest marketers.
Which is why so much is riding on a Food and Drug Administration decision expected soon on whether and how to regulate e-cigarettes.
Some states have stepped in. New Jersey bans sales to people 19 and under, and the use of e-cigs in indoor work and public spaces. In Pennsylvania, anyone of any age can buy and use them anywhere.
E-cigarettes don't burn and don't produce tobacco smoke, which contains dozens of known carcinogens. Instead, electric current from a battery heats a liquid containing nicotine. The resulting vapor is inhaled, mimicking the feel (and look) of tobacco smoke with what more closely resembles steam. Nicotine - the ingredient that causes addiction but that is not necessarily harmful - provides the kick.
Although research is ongoing, it seems likely that vaping will prove safer than smoking, which the Centers for Disease Control and Prevention estimates leads to more than 440,000 deaths per year.
That alone supports a public health point of view - embraced by the industry and cited by every vaper in this article - known in the field as harm reduction. It's the philosophy behind methadone maintenance for people addicted to heroin. It prevents deaths by accepting the lesser of two evils.
Danny McGoldrick takes the other view.
"We need to look beyond that very narrow question of 'Are they less harmful than cigarettes?' " said McGoldrick, vice president of research for the Campaign for Tobacco-Free Kids. Former smokers might be brought back, he said. Sponsoring sporting events and marketing flavors like bubble gum - both prohibited for regular cigarettes - might lure youngsters who would not have smoked.
"It all comes down to, are these going to be used to decrease smoking or to increase smoking?"
Anyone who has tried to quit would be hard-pressed to recognize that experience at Ecigs International, a new e-cigarette store and vapor lounge on Green Lane in Roxborough. A handful of customers sit around blowing "clouds" and talking about the merits of different products.
Most people there started with more basic disposables, the products that look like an oversize cigarette, battery included, provide puffs equal to about a half-dozen regular cigarettes, and cost $7 to $12 in convenience stores. Now they favor rechargeables, which come with external chargers and which can be customized with a range of atomizers - the heating element that turns nicotine liquid into vapor - and varieties of the "e-juice" that feeds them; the store mixes 150 to 200 flavors with a range of nicotine contents.
"I had open-heart surgery 13 years ago and a heart attack three years ago," said Robin Patterson, 48, who drives from her home in Allentown, N.J., east of Trenton, for supplies. She was unable to quit smoking until July, she said, when her brother suggested an e-cigarette.
She gets the same "throat hit" as with regular cigarettes, and the electronic varieties offer the same "oral fixation."
She showed off her new black chrome Vamo V3, a complete $110 kit that she supplemented with a $22 Kangertech Protank II atomizer that holds more e-juice, of which she bought two bottles, guava and spearmint, each with 24mg of nicotine. Total cost: $149. The e-juice will last a month and a half; the rest, in theory, could work for years. Yet the total cost equals two weeks of her old 11/2-pack-a-day Virginia Slims habit.
She has set a personal goal of reaching zero nicotine level within a year by buying liquids with lower content every four months. Meanwhile, she vapes wherever she wants - home, the car, at work as a corporate relocation manager, even once flying from Newark to Chicago.
"I don't cough anymore," Patterson said. "The blessing is that I don't smell like an ashtray anymore."
E-cigarettes make up just one percent to two percent of $90 billion in tobacco sales. But an August report by Goldman Sachs predicted a rise to 20 percent by the end of the decade. Another top analyst projected last month that e-cigarette revenue would exceed that from cigarettes by 2021 for Reynolds American Inc., which sells both.
The three big tobacco companies recently created or bought e-cigarette brands, among them Lorillard Inc.'s blu eCigs, the market leader, along with privately held NJOY.
The original e-cigarettes were bulky rechargeables. NJOY, founded in 2006, introduced the first disposable two years ago, instantly changing the market. NJOY set the stage for the current regulatory vacuum when it successfully sued to stop the FDA's plan to classify e-cigarettes as drug-delivery devices.
The agency now plans to regulate e-cigarettes under the 2009 law that authorized it to oversee tobacco. It cannot ban them, as Japan, Brazil, and Mexico have. It can regulate e-cigarettes marketed as cessation tools, requiring evidence from clinical trials. And it could approve messages that they are less harmful than cigarettes, but only if manufacturers submit evidence of a net benefit to public health.
Observers expect some version of tobacco rules, which allow the FDA to test safety, restrict sales to minors - and, in the case of regular cigarettes, limit self-service displays and the sports and entertainment sponsorships known to increase sales.
Marketing limits would be too much for Craig Weiss, CEO of NJOY, who said he supports "reasonable regulation." But given the death toll from tobacco - "basically a 9/11 every three days," he said - "I don't want them to restrict our ability to advertise our product."
Many longtime tobacco researchers are pressing for restrictions, hoping to prevent a new generation from getting hooked before evidence proves e-cigarettes are safe.
Some have found harmful ingredients. Perceptions that e-cigarettes can help smokers quit far outstrip the evidence, they say.
No one knows how they will be used in the long term.
"There may be people who use this exclusively for their [entire] life and we need to know how it will affect them," said Andrew Strasser, an associate professor of psychiatry at the University of Pennsylvania who is enrolling cigarette smokers in a study to see how they respond to e-cigarettes. "Others may use it for a short time," he said. Still others may add e-cigarettes to an existing cigarette habit.
His conclusion: "More evaluation needs to be done before you make a decision either way."