Editor’s note: This post is part of a series stemming from the Third Annual Health Law Year in P/Review event held at Harvard Law School on Friday, January 30, 2015. The conference brought together leading experts to review major developments in health law over the previous year, and preview what is to come. A full agenda and links to video recordings of the panels are here.

Sometime in the next few months, the Food and Drug Administration (FDA) is expected to issue the so-called deeming regulations, which will open the door to the federal regulation of e-cigarettes. In considering whether to issue the regulations, which were first published for notice and comment rulemaking last April, the FDA faces a formidable challenge: it must decide whether and how to regulate in the midst of scientific uncertainty and limited statutory flexibility.

By subjecting e-cigarettes to its regulatory regime, the FDA risks retarding the growth of what may prove to be a powerful new tool for harm reduction. But by failing to act, the agency risks undermining decades of progress in tobacco control. In either case, the public health impact is apt to be significant.

It is a victory that was made possible, in large measure, by a constellation of state and federal regulatory interventions: laws regulating the marketing and sale of cigarettes, barring sales to youth, banning indoor smoking, and taxing cigarette sales have all played a role in reducing rates of smoking.

Nevertheless, smoking remains stubbornly common, especially among teens. According to the Centers for Disease Control, in 2012 an estimated 18.1 percent of the U.S. adults were smokers as were 14 percent of high school students. Each year over 480,000 Americans die of smoking-related diseases.

It is in this environment that the market for e-cigarettes has developed since they were first introduced in the U.S. less than ten years ago. By 2013, over 47 percent of smokers had tried e-cigarettes; and 4 percent were regular users. In 2013 more than 250,000 minors who had never smoked had used an e-cigarette.

Although they take many forms, e-cigarettes, also known as electronic nicotine delivery systems (ENDS), or more colloquially as vapes, use battery power to heat and vaporize liquid nicotine that users inhale. In contrast to traditional cigarettes, pipes, and cigars, there is no combustion.

Supporters contend that e-cigarettes can serve as a form of harm reduction, akin to the needle exchange programs that have been used to stop the spread of HIV by intravenous drug use. Less dangerous than cigarettes, e-cigarettes deliver nicotine without exposing users and bystanders to the byproducts of combustion. Therefore they may allow users to get their nicotine “fix” and the sensory pleasures of smoking without being exposed to, or exposing others to, cigarette smoke.

Critics, in contrast, argue that e-cigarettes are not as harmless as they seem. For a start, they expose users to nicotine, a highly addictive drug, which has been associated with numerous health effects. Moreover, studies have shown that the vapor produced by e-cigarettes sometimes contain heavy metals and other toxins.

For example a recent letter to the editor of the New England Journal of Medicine reported on research finding that high voltage vaping may expose users to more than 4 times the amount of formaldehyde presented by traditional cigarettes. And because there are over 400 brands on the market, and most of them are imported, the risk of adulteration is high, as a recent New York Times article pointed out.

Critics also worry that the growth of vaping will lead to more smoking. In particular, they point to the common practice of adding sweet flavors to e-cigarettes and argue that this attracts young people, who may become addicted to nicotine and then “graduate” to conventional cigarettes. There is also concern that the advertising and use of e-cigarettes in public places will renormalize smoking, thereby reversing the change in social norms that has helped support reductions in rates of cigarette usage.

Regulatory Challenges

The challenge for regulators is that the science is not yet settled. In its notice of proposed rulemaking, the FDA admitted that it did “not currently have sufficient data about these products to determine what effects e-cigarettes have on the public health.”

Although the weight of the evidence establishes that e-cigarettes are less harmful than cigarettes, it is simply too early to know the long-term dangers for users or bystanders. Moreover, we don’t know if the proliferation of e-cigarettes will increase or reduce overall rates of smoking. In other words, we just don’t know whether e-cigarettes will prove to be an effective form of harm reduction or a gateway drug.

Adding to the regulatory challenge are the limitations imposed by the federal statutory scheme. In 2010 a federal appeals court ruled that the FDA could not act against adulterated e-cigarettes under the Food, Drug and Cosmetic Act; rather its authority was limited to that provided by the 2009 Tobacco Control Act (“TCA”). That Act imposes regulations on specified tobacco products, such as cigarettes and smokeless tobacco, and all other tobacco products that the FDA “deems” to be subject to the Act. It is this provision that the FDA will invoke if it promulgates the deeming regulations.

In the midst of the scientific uncertainty, it might seem sensible for the FDA to exercise caution, and promulgate only those regulations—such as limitations on youth sales, bans on adulteration, and requirements for warning labels—that are non-controversial (even industry purports to support such measures). The FDA, however, believes that it does not have the statutory authority to pick and choose among the provisions of the TCA.

In other words, if e-cigarettes are deemed to be tobacco products, a wide range of regulations will automatically come into effect. Most notable is the requirement that new products undergo pre-market review. This review is simplified for products that are substantially equivalent to ones that were on the market in 2007. But because the technology used in e-cigarettes has rapidly evolved, it appears that there were no products substantially similar to most current e-cigarettes on the market in 2007.

Hence, if the deeming regulations are promulgated, e-cigarettes will be subject to full premarket review, an expensive and timely process. To mitigate the impact, the FDA has proposed to use its enforcement discretion to allow products to stay on the market for 24 months from the time the regulations are promulgated. Even with this grace period, however, premarket review may pose a significant barrier to small brands, some of which may be better suited to harm reduction than the products marketed by big tobacco.

Stand Back? Or Step In?

Given the statute’s inflexibility, and the scientific uncertainty, it might seem sensible for the FDA to stay its course until the science is settled. During such delay, state and local governments could continue to develop their own regulatory responses to e-cigarettes. Already four states have applied some or all of their indoor smoking laws to e-cigarettes; as have almost 200 cities. Many local jurisdictions also ban youth sales. These more localized regulations may serve as the laboratories of democracy that will allow us to gather evidence about the impact of e-cigarettes, and their regulation, on smoking rates.

On the other hand, state and local governments have far more limited regulatory tools at their disposal than does the FDA. In particular they cannot prevent adulteration, and they have less authority over labeling. Moreover, because some e-cigarettes deliver higher doses of nicotine than do traditional cigarettes, the risks of addiction are high. As a result, once e-cigarettes become firmly established in the market—especially among young people—it may be become quite difficult to implement effective regulatory responses.

In the ideal world, the solution would be for Congress to amend the TCA to permit the FDA to exercise greater discretion as to which regulations should apply to e-cigarettes. This would permit the FDA to impose youth bans, bans against adulteration, and labeling requirements, while waiting on a wider range of measures. Given the politics in Washington, however, that’s not likely to happen. Congressional gridlock thus joins scientific uncertainty as yet another challenge confronting the FDA.