WASHINGTON — ELECTRONIC cigarettes, battery-powered devices that convert a solution of nicotine and other chemicals into a vapor that can be inhaled, or “vaped,” have the potential to wean a vast number of smokers off cigarettes. No burned tobacco leaves, no cancer-causing tar: a public health revolution in waiting.

The problem is, not enough smokers are switching to e-cigarettes, despite their relative safety — and understandably so. Smokers are barraged with news about inaccurate labeling, shoddy counterfeits and poorly made e-cigarettes that emit toxins and cancer-causing chemicals in vapor. And to the frustration of smokers, public health experts and, yes, manufacturers, the Food and Drug Administration, which has not yet set up sensible regulations, is making the situation worse.

There’s no doubt that the initial public enthusiasm over e-cigarettes is waning: A report last year in the American Journal of Preventive Medicine showed that while nearly 85 percent of smokers believed that e-cigarettes were safer than cigarettes in 2010, that number had dropped to 65 percent in 2013.

Quality concerns are likely to keep rising: This year Chinese manufacturers, the most frequent culprit in safety oversight, are expected to ship more than 300 million e-cigarettes to the United States and Europe. Many of these products will be perfectly safe; the issue is that, so far, we lack an effective regulatory regime to distinguish the good from the bad.