"So much is unknown about them and what the long-term complications could be with their use," said the American Lung Association's Erika Sward. "Bottom line, we don't know what the consequences of using them are, and we are very troubled that kids would find them attractive."
E-cigarettes are unregulated in the United States; no laws make manufacturers tell you what you are actually inhaling. The unknown is one of the many qualities of e-cigarettes that the American Lung Association doesn't like.
It's "a complete unregulated Wild West," Sward said. She wants the FDA to move quickly with regulatory oversight, which she says would make manufacturers disclose what the actual ingredients are in each of the 250 or so brands available.
In 2009, a FDA test on a small number of e-cigarette samples found "detectable levels of known carcinogens and toxic chemicals to which users could potentially be exposed." They found diethylene glycol in one cartridge at a 1 percent level; this is an ingredient used in antifreeze and can be toxic to humans in large quantities. Diethylene glycol is also found in some dental products and in some pharmaceuticals.
After that study, the FDA banned the sale of e-cigarettes. They warned e-cigarette smokers that they were inhaling "toxic" and "harmful" chemicals. However, in 2010, a court ruled that "the FDA had cited no evidence to show that electronic cigarettes harmed anyone," and stores could go on selling them.
The early e-adopters
On the other side of the debate are the passionate supporters of e-cigarettes. Many who use them say it is the first thing that has helped them stop using cigarettes -- something more than 90 percent of smokers fail to do with any of the existing FDA-approved methods. There are blogs and message boards dedicated to them. And there are countless impassioned testimonials from the people who use them.
Florida resident Craig Lashley says they've changed his life.
"I got tired of being like that little kid in 'Peanuts' who had the cloud of smoke following him all the time," Lashley said. "I didn't like the way I smelled when I smoked, and I didn't like what smoking said about me, especially to kids."
He discovered the e-cigarette about a year ago and hasn't smoked a regular cigarette since.
He says he smells better, feels better and spends a lot less -- about $10 a week on e-cigarettes. He used to spend about $45 a week on regular cigarettes.
"I like the feel of blowing smoke," Lashley said. "It seems to me like (e-cigarettes are) a healthier alternative."
A growing number of respected physicians and scientists agree, and they say these products could end a major health problem.
"Electronic cigarettes and other nicotine-containing devices offer massive potential to improve public health, by providing smokers with a much safer alternative to tobacco," the Royal College of Physicians says. "They need to be widely available and affordable to smokers."
The latest study, published in the British journal the Lancet, examined whether people who used them as an alternative to smoking would abstain from using regular cigarettes.
The New Zealand authors studied the behavior of 657 people who were trying to quit. One group got nicotine patches, another got nicotine e-cigarettes and others got placebo e-cigarettes without the nicotine.
Over a period of six months, only a tiny fraction of the people in the study actually quit smoking.
People using the nicotine e-cigarettes quit at a slightly better rate compared with those using the patch, though. Some 7.3 percent using the e-cigarettes abstained from smoking traditional cigarettes compared with the 5.8 percent who stopped with the patch. About 4.1 percent stopped with just the placebo e-cigarettes.
It was such a small number of people who quit that the authors concluded "more research is urgently needed to clearly establish their overall benefits and harms at both individual and population levels."
Dr. Michael Siegel, a physician who has spent the past couple decades working on tobacco control initiatives, has been surprised by the negative reaction to e-cigarettes from so many people in the public health sector. Siegel says the studies he's done have shown e-cigarettes are a help.
"True we don't know the long-term health effect of e-cigarettes, but there's a very good likelihood that smokers are going to get lung cancer if they don't quit smoking," he said. "If they can switch to these and quit smoking traditional cigarettes, why condemn them?"
Siegel theorizes the e-cigarettes might look too much like smoking.
"It's ironic the very thing that makes them so effective ... drives the anti-smoking groups crazy. But what makes them so effective is it mimics the physical behaviors smokers have, which is something the patch can't do."
Siegel does believe there is an urgent need for more regulations.
Ray Story, founder of the Tobacco Vapor Electronic Cigarette Association, agrees. He says his association has also pushed for age verification legislation.