The Case for Tolerating E-Cigarettes DEBATE over e-cigarettes - battery-powered cigarette look-alikes that heat liquid nicotine but emit a harmless vapor - is raging. New York City and Chicago are considering adding e-cigarettes to their bans on smoking in bars, restaurants and parks, and Los Angeles is moving to restrict e-cigarette sales, even though e-cigarettes don't generate smoke and, while not proved to be entirely safe for users, are undoubtedly less hazardous than tobacco cigarettes. The evidence, while still thin, suggests that many e-cigarette users, hoping to kick the habit, use e-cigarettes as a safer alternative to tobacco. Research also suggests that e-cigarettes may be better at helping to sustain smoking cessation than pharmaceutical products like nicotine patches or gums. No one believes nicotine addiction is a good thing, and our qualified support for e-cigarettes is not one we reach lightly. Although some e-cigarette manufacturers have no links to the tobacco industry, Big Tobacco is consuming an ever-greater share of the e-cigarette market. It is hard for public health advocates like us to look favorably on anything the industry wants. But history shows that harm reduction - the doctrine that many risks cannot be eradicated and that efforts are best spent on minimizing the resulting harm - has had an important place in antismoking efforts and suggests that regulation is better than prohibition. It's been only a half-century since the federal government took an interest in making tobacco products safer. In 1964, Surgeon General Luther L. Terry issued a watershed report definitively linking smoking with lung cancer. But he also described research into new kinds of cigarettes as "a promising avenue for further development." In the early 1970s, the government spent some $6 million a year to try to develop safer tobacco products. Even the health secretary Joseph A. Califano Jr., who called smoking "Public Enemy No. 1," saw, in 1978, a place for "research aimed at creating a less hazardous cigarette." As late as 1981, the surgeon general advised smokers who couldn't or wouldn't quit to switch to low-tar and low-nicotine brands. The American Cancer Society, while worried that the development of less hazardous cigarettes might derail efforts to deter people from smoking or getting them to quit, supported "frank scientific discussion about the possibilities of developing cigarettes that will be less harmful and still satisfying to smokers." This effort came to a halt in the 1980s, when stunning revelations from high-profile court cases demonstrated that the tobacco industry had lied about the dangers of smoking for decades and even manipulated the levels of nicotine in its products to ensure that smokers stayed hooked. The magnitude of the deception made it nearly impossible to consider the possibility of a "safer" tobacco product. It inspired, among advocates, opposition to anything less than total cessation. This new stance was supported by the availability of over-the-counter nicotine replacement therapies and a focus on protection of bystanders from secondhand smoke. As the head of the American Heart Association put it in 2000: "There is no such thing as a safer cigarette." The irony is that, during these same years, AIDS prompted public health advocates to support needle exchange for users of intravenous drugs, a harm-reduction approach that also drew fire from those who favored complete elimination of drug use. Fears that such programs would lead to greater illicit drug use have been definitively put to rest. Of course the analogy is not exact: Unlike clean needles, which present no independent harms to injecting drug users, less risky alternatives to smoking, like smokeless chewing tobacco and the moist tobacco product known as snus, carry a grave risk: oral cancers. E-cigarettes potentially overcome that barrier. Most experts consider nicotine harmful only at extremely high doses. Tobacco control advocates tolerate the long-term use of therapies like the nicotine patch and nicotine gum despite their approval only as temporary smoking-cessation aids. In 2000, the chairman of a Public Health Service panel called tobacco dependence a "chronic condition that warrants repeated treatment," even if that meant treating smokers "for the rest of their lives." Advocates fear that e-cigarettes will serve as a gateway to deadly cigarettes - or sustain smokers in public settings where lighting up is banned. "Waiting to act," New York City's health commissioner, Thomas A. Farley, said, "is a risk we should not take." But there is a price to such rigidity. Emotion should not rule out harm reduction, even if eradication of smoking is the ultimate goal. Banning vaping in public won't help. Instead, e-cigarettes should be regulated by the Food and Drug Administration as products "sold or distributed for use to reduce harm or the risk of tobacco-related disease." The industry can't be trusted to provide safer products. The historical mistake was not the pursuit of a safer cigarette, but championing that cause with dishonest partners. If e-cigarettes can reduce, even slightly, the blight of six million tobacco-related deaths a year, trying to force them out of sight is counterproductive. Amy L. Fairchild is a professor, and James Colgrove is an associate professor, of sociomedical sciences at the Mailman School of Public Health at Columbia.