Regulators in the U.S. see e-cigarettes as a threat. See FDA Threatens to Pull E-Cigarettes to Fight the Rise of Kids Vaping.
A report released by the Science and Technology Committee in Parliament last month found e-cigarettes "substantially less harmful" than conventional cigarettes. The report recommends relaxing regulation so that approval of e-cigarettes can be "streamlined" and asks policymakers to reconsider allowing their use in public places.
The report also found no evidence that vaping is a gateway to traditional cigarette smoking for teens.
Also note this from parliament.uk/
In 2016, the Royal College of Physicians concluded that:
Large-scale substitution of e-cigarettes, or other non-tobacco nicotine products, for tobacco smoking has the potential to prevent almost all the harm from smoking in society. Promoting e-cigarettes, [Nicotine Replacement Therapy] and other non-tobacco nicotine products as widely as possible, as a substitute for smoking, is therefore likely to generate significant health gains in the UK.
U.S. regulators should be paying attention to what's happening in the U.K. in regard to e-cigs.
1:13 PM 9/20/2018