Dear Cecil: In a staff report on your site about whether nonsmoking actors use fake cigarettes when playing a part, the writer said there's no such thing as noncarcinogenic smoke, implying smoke is the primary danger. What about the new electronic cigarettes — since they're smokeless, are they noncarcinogenic? Amit Anand

Cecil replies:

Well, that’s the theory. Browsing online, we find claims like this: “[Our] premier line-up of smokeless electronic cigarettes utilizes innovative technology to provide a smoking experience without the dangers, hassle and even expense of traditional cigarettes.” Here one recalls the miracle drug diacetylmorphine, introduced in 1898 as a nonaddictive alternative to morphine by the German drug company Bayer, which also gave the world aspirin. Diacetylmorphine is better known by its trade name, Heroin. You see how well that worked out.

Like traditional smokes, electronic cigarettes, or e-cigarettes, are a nicotine delivery device. The difference is that whereas the paper-and-weed variety involves burning tobacco and inhaling the smoke, e-cigarettes merely heat nicotine to produce vapor, and you breathe that — hence the vernacular term for this activity, “vaping.”

An e-cigarette consists of a mouthpiece, a battery, some electronics, a filament-type heater, and a disposable cartridge containing a mix of nicotine, propylene glycol, glycerin, and flavorings. When the electronics detect that the smoker has taken a drag, they switch on the heating element, warming air that’s then pulled through the cartridge, vaporizing some of the nicotine mix for easy inhaling. Many e-cigarettes are designed to mimic the tobacco kind, often with a colored LED tip that glows when the user inhales. However, other less literal-minded formats abound. For those who like wearing tweed and driving cranky British automobiles, an e-pipe version is available.

These things clearly have their advantages. The absence of combustion means no combustion byproducts — including tars, carbon monoxide, and other noxious chemicals — and also no risk of fires and burns. Those in the user’s vicinity don’t choke on tobacco smoke, although if you sit too close you can still get a snootful of secondhand vapor.

Relatively little research has been done on e-cigarettes since their appearance on the market roughly six years ago. However, while it would be foolish to say they’re harmless, studies so far suggest they’re orders of magnitude safer than conventional cigarettes.

In investigating e-cigs, the FDA has focused on two types of chemicals: tobacco-specific nitrosamines (TSNAs), which are carcinogenic, and diethylene glycol (DEG), a plain old poison. E-cigarettes were found to provide a 500- to 1400-fold reduction in TSNAs compared to traditional cigarettes, and DEG was found in only one cartridge tested. Of 16 studies reviewed in 2010, none found more than trace amounts of the carcinogens typical of tobacco smoke in either the nicotine solution or the vapor thereof. Nonetheless, since there’s no minimum safe level of a carcinogen, the FDA still warns against e-cigarettes.

Although you’re not sucking in smoke with e-cigs, you are inhaling vapor, which can be problematic. One study I came across reported that vaping for just five minutes made breathing more difficult. The propylene glycol in the nicotine solution can cause respiratory inflammation and increase asthma risk.

A test of 35 nicotine refills in various flavors found several were toxic to human cells, primarily due to the flavorings. Another study found that because of contamination by the heating filament, some vapor contained tiny particles of silica and metals such as tin, nickel, and chromium. Nine of eleven elements found in e-cigarette vapor were at an equal or higher concentration than that found in conventional cigarette smoke, with what fell implications no one knows.

The main thing, though, is that e-cigarettes can help reduce or eliminate smoking, even among those not trying to quit. Researchers in Italy furnished a group of volunteer smokers with e-cigarettes, excluding anyone who was consciously trying to stop smoking and providing no encouragement to do so. Despite this, 22 of 27 participants had reduced their consumption of conventional cigarettes by at least 50 percent after six months and nine had quit altogether.

Other studies have found that despite delivering minimal nicotine, e-cigarettes satisfy regular smokers and significantly reduce the craving to smoke. Compared to things like nicotine patches, e-cigarettes may make it easier to stop smoking because they preserve the ritual of holding a cigarette, taking a puff, and exhaling visible fumes. E-cigarette users we’ve talked to unanimously report the product is a passable substitute for the real thing, although some say they still smoke an occasional cigarette when under peer pressure.

Overall, notwithstanding my instinct that all change is for the worse, the evidence to date strongly suggests e-cigarettes beat smoking, which kills 443,000 Americans annually and is notoriously hard to stop doing — among people who try to quit on their own, 80 percent relapse within a month. Long-term research on health impacts is needed, and no doubt breaking the nicotine habit altogether is preferable to vaping. But e-cigarettes look like a good plan B.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.