As indoor bans on electronic cigarettes or "e-cigarettes" go into effect in New York and in Chicago, advocates of the bans continue to argue nicotine in e-cigarettes can tip people toward to addiction.
"They are nicotine delivery devices intended to be used like a cigarette," says Dr. Norman Edelman, the American Lung Association's chief medical officer. "What happens to someone who stops inhaling the tars of cigarettes and inhales only nicotine? We don't know. There is at least the potential for harm."
Chicago and New York are joining San Francisco and Los Angeles in enacting bans aimed at the e-cigarettes, which are often attractive to teenagers for their candy flavors and celebrity endorsements.
Dr. Tom Frieden, director of the Centers for Disease Control and Prevention, does not mince his words when it comes to the tobacco-free but nicotine-delivering devices.
"To me, as a physician, when 1.78 million of our high school kids have tried an e-cigarette and a lot of them are using them regularly ... that's like watching someone harm hundreds of thousands of children," Frieden told the Los Angeles Times in an interview.
"I've treated so many adults who are desperate -- desperate -- to get off tobacco. They all started as kids," Frieden added. "I see the industry getting another generation of our kids addicted."
Frieden called the move by the Federal Drug Administration forbidding the sale of e-cigarettes to minors and requiring manufacturers to put health warning on the devices "a good first step."
While acknowledging some people have used e-cigarettes to quit smoking tobacco cigarettes, he says he still sees a strong need for regulation.
"If the e-cigarette companies want to market these to help people quit, then do the clinical trials and apply to the FDA," he said. "But they don't want to do that. They want to market them widely."
In Chicago, health organizations applauded the new ban, which adds e-cigarettes to a prohibition on smoking in restaurants, bars and most public buildings.
"Laboratory studies have shown that e-cigarette vapor contains chemicals such as nicotine, formaldehyde, [and] arsenic," said Joel Africk, head of the Respiratory Health Association of Metropolitan Chicago.