Marc Scribner is a fellow at the Competitive Enterprise Institute, a free-market think tank in Washington, D.C. He specializes in transportation and telecommunications policy issues. CEI has received funding from the tobacco industry and e-cigarette industry in the past. The opinions expressed in this commentary are solely those of the author.

(CNN) These are good times for anti-smoking campaigners. But you wouldn't know it from listening to their rhetoric. At the urging of anti-tobacco activists, the Department of Transportation is proposing to ban electronic cigarette use aboard aircraft.

This impending regulation not only defies medical evidence but makes a mockery of the law in the process.

The use of e-cigarettes among U.S. adults more than doubled between 2010 and 2013, according to the Centers for Disease Control and Prevention . The tobacco industry predicts e-cigarette sales will surpass traditional cigarettes in the coming decades. This signals great progress from a harm-reduction standpoint, since the best available scientific evidence suggests that while e-cigarettes may bring health risks, they are far smaller than those associated with tobacco smoking.

Yet, anti-tobacco campaigners are increasingly agitating for strict rules against e-cigarette use, perversely threatening advances in public health.

The risks associated with e-cigarettes are borne exclusively by the users, not the people around them . Unlike tobacco cigarettes, vaporizers do not produce harmful "sidestream" emissions -- the smoke released directly into the air from the end of lit cigarettes, which produces 85% of secondhand smoke and virtually all of its associated risks.

As for the "mainstream" smoke inhaled by smokers, many of its harmful compounds are partially retained within the smoker's body, which acts as a filter before it is exhaled into the surrounding air.

There is simply no evidence that secondhand aerosols exhaled by e-cigarette users endanger non-users. As Dr. Joel Nitzkin, a former co-chair of the Tobacco Control Task Force of the American Association of Public Health Physicians, said , "[T]here is no public health justification for banning e-cigarette use in no-smoking areas."

Anti-tobacco activists who disingenuously equate vapor and tobacco smoke may perversely convince smokers to reject far safer e-cigarette alternatives. Consumers should not be misled to believe e-cigarettes, which do not produce tobacco smoke and its many concentrated toxins, pose the same risks as smoked tobacco.

To be sure, airlines should be free to ban e-cigarettes aboard their aircraft if they so choose. But just like the use of cell phones on planes (or a passenger's odoriferous perfume, for that matter), the risks posed by e-cigarettes do not justify federal regulation.

In 2011 , the Department of Transportation initiated a regulatory proceeding to reinterpret "smoke" and "smoking," in order to extend the existing federal ban on in-flight smoking to e-cigarettes. Now years delayed, the department quietly indicated in mid-January that it plans to finally issue a rule by the end of April to prohibit e-cigarette use aboard aircraft. Such an action runs counter to congressional intent and constitutes an illegal expansion of regulatory power.

The DOT states that Congress' intent in prohibiting smoking in the skies was to "improve air quality within the aircraft, reduce the risk of adverse health effects on passengers and crewmembers, and enhance aviation safety and passenger comfort." The law was intended to address secondhand smoke, and the department concedes "a vapor, rather than smoke, is produced." So how does the Department of Transportation justify its proposal? By noting, that e-cigarettes "require an inhalation and exhalation similar to smoking cigarettes."

So, by DOT's logic, when Congress referred to "smoke" and "smoking," it meant anything that might vaguely resemble smoke and smoking, rather than smoke itself and its resulting harms, even though Congress enacted a clear law in which the terms "smoke" and "smoking" are not ambiguous.

The Department of Transportation has no authority to regulate vaping, an area over which it has no jurisdiction. It may claim that it is simply interpreting "smoking" to cover the use of e-cigarettes, but as the Supreme Court has made it clear , an "agency may not bootstrap itself into an area in which it has no jurisdiction" by stretching the language of a statute.

Regardless of one's views on whether airlines should permit e-cigarette use on their flights or not, the Department of Transportation's attempt to rewrite a law passed by Congress is an unlawful abuse of power. The looming in-flight e-cigarette ban has far more to do with pushing a nanny-state agenda than promoting illusory public health benefits.