Introduction

Electronic nicotine delivery systems (ENDS) are commonly known as electronic cigarettes or e-cigarettes and vape pens. These devices are meant to deliver nicotine by heating up a vape liquid into an inhalable aerosol. The vape liquid is a solution containing nicotine, flavoring agents, and solvents such as propylene glycol or glycerin [1]. The e-cigarette was first invented by Herbert A Gilbert in 1963, but the subsequent commercially viable design was patented by Hon Lik of China [2]. E-cigarettes entered the US market in 2007 [3] and have gained tremendous popularity since, especially among youth. E-cigarettes were marketed as a safer alternative to conventional combustible cigarettes and therefore were promoted as harm reduction substitutes for current smokers. However, there are contrasting claims associated with e-cigarettes being considered as a safer alternative to conventional cigarettes. The bottom-line according to the Centers for Disease Control and Prevention remains that e-cigarettes are possibly a less harmful alternative for current smokers addicted to combustible cigarettes [4••]. E-cigarettes are not for people who have never smoked in their life, and even establishing their efficacy as a smoking cessation tool needs thorough and long-term research [5]. The dangers of e-cigarette vaping include damage to the developing brain from nicotine [6,7,8] and exposure to toxic substances such as heavy metals, volatile organic compounds, and ultrafine particles [9, 10•].

Public Health Consequences

The adverse health consequences of e-cigarette use for both primary smokers and those exposed to secondhand smoke arises from the inhalation of the e-cigarette aerosol and levels of nicotine delivered into the system [11, 12].

Nicotine is known to be acutely toxic at high doses, and cases of nicotine poisonings due to vape liquids have seen a rise in recent years [13]. Nicotine is also a pharmacologically active biomolecule that sustains addiction, changes the way one’s brain functions [14], and is known to have particularly harmful consequences on the growing fetus if exposed to it during pregnancy [15, 16].

The e-cigarette aerosol contains a vast array of chemicals including any number of approximately 7000 flavorings [17], humectants such as Propylene Glycol and Vegetable Glycerin and contaminants such as metals, formaldehyde, acrolein, and tobacco-specific nitrosamines [1, 18] all with the potential to cause a wide variety of negative health effects. A list of these compounds and their physiologic effects are outlined below (Table 1).

Table 1 Constituents of ENDS Aerosol [19]
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Need for Regulation

In the years before the advent of ENDS technology, various public health measures made significant progress in tobacco control yielding a 6.9% reduction in smoking across the US population from 2005 to 2017 [32,33,34,35]. Keeping in mind the economic and social burden exacted by smoking-related diseases, the Federal Government had enacted various laws to make the sale of conventional tobacco products more difficult especially for the younger generation. However, rapid and unchecked increase in e-cigarette use [10•, 36] has once again threatened to endanger the health of our youth through nicotine addiction and vaping related disease [6, 37]. The National Youth Tobacco Survey held jointly by the FDA and the Centers for Disease Control and Prevention shows that around 3.6 million students (both middle and high school) were using e-cigarettes in 2018, up from 2.1 million in 2017 [38, 39]. There is emerging evidence that e-cigarettes can spur future tobacco product use in teens, whereas, on the other hand, banning tobacco products diminishes the smoking risk. Socio-economic background is another factor that also plays a major role in smoking initiation [40,41,42].

Another area of concern is the public health consequences of secondhand e-cigarette smoke on bystanders. Though the country has made significant progress in enacting clean air laws in public places including workplaces and indoors, a lot still remains to be done. The use of e-cigarettes in public areas poses a serious health risk considering the various toxic constituents that have been shown to affect both the primary smoker and victims of passive smoking. It is pertinent to note that smoke-free laws in the USA were passed before ENDS entered the market and do not specifically mention the prohibition of e-cigarette smoking in many places. As such, this non-clarity may lead to non-compliance or exploitation of smoke-free rules [43, 44].

Existing Regulation

Federal Regulations

The FDA has been regulating tobacco products since June 2009; a timeline of the most important regulations is furnished in Table 2.

Table 2 Timeline of policies/rules/regulations enforced at the federal level
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On May 10, 2016, the U.S. Food and Drug Administration (FDA) passed a new rule effective August 08, 2016, deeming that all tobacco products be brought under the purview of Federal Food, Drug, and Cosmetic Act thus authorizing the FDA to regulate all tobacco products including ENDS [46]. Apart from banning the sale of e-cigarettes to those below 18 years of age, the rule also stipulates several manufacturing standards and marketing limitations. The rule focuses on preventing a younger generation from becoming addicted to nicotine through e-cigarettes while taking into account the harm reduction potential of e-cigarettes for existing smokers addicted to nicotine.

More recently, in light of the 2018 National Youth Tobacco Survey, the FDA and Federal Trade Commission (FTC) issued warnings to four e-cigarette manufacturing companies around youth-focused advertisement, sale and distribution of ENDS products, especially on social media platforms [47].

State Regulations of e-Cigarettes

The US state and local governments have played a proactive role in enacting several laws at their level to protect against the misuse of e-cigarettes. In June 2019, San Francisco, California, became the first city in the USA to ban the retail and online sale of e-cigarettes. This move is especially significant as Juul Labs, Inc., the makers of the Juul e-cigarettes variety, which has captured 70% of ENDS market share in recent years, is based out of San Francisco. Another trend is the implementation of Tobacco 21 laws in several states, increasing the minimum age of sale of tobacco products from 18 to 21. As of June 2019, 16 states, Arkansas, California, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, New Jersey, Oregon, Texas, Utah, Vermont, Virginia, and Washington, the District of Columbia and 470 localities had implemented tobacco 21 laws [48].

As of April 2019, 13 states, 2 territories, and 841 municipalities have banned the use of e-cigarettes in 100% smoke-free public places [43]. In addition, regulations defining e-cigarettes, taxation, packaging, access to youth, and licensure of e-cigarette sales have been put into place across several states (Table 3).

Table 3 Law(s) in effect across all States & the District of Columbia in the USA (March 15, 2019) [49]
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Challenges and Recommendations

A review of the scientific literature shows largely incomplete data around the health effects of e-cigarettes. This translates to policy indecision among the regulatory authorities leading to confusion among the general public. This also causes problems for health care professionals in counseling current smokers looking to switch to e-cigarettes [50,51,52]. A long-term comprehensive study involving all major stakeholders is required to address this problem.

A bi-pronged approach could be key in balancing the regulatory aspects of e-cigarettes. It should consist of a prevention strategy in case of youth and a control strategy for current smokers who are looking at reduced harm alternatives for their nicotine fixation [53]. The prevention aspect can include laws that prohibit sale to minors, prevent youth-targeted advertisement campaigns [54, 55] and flavors, child-safe packaging, and campaigns addressing awareness and education. On the other hand, the control aspect can include better manufacturing measures, licensing laws for retail and online sale, selective taxation, and supervised subsidy for verified current smokers.

Conclusions

Every once in a while, a newer technology emerges onto the market and causes a massive shift in the prevailing status quo. E-cigarettes are one such technology that emerged a decade ago and has changed the way tobacco is consumed by the current population. It has brought along with it many dangers but also some promises. The regulatory framework has to tread a narrow path of prevention and control to safeguard future generation against the evils of tobacco as well as other unintended health consequences of using ENDS, but at the same time ensure that the path from combustible cigarettes to e-cigarettes ends with complete smoking cessation.