Disposable e cigarettes and their nicotine delivery, usage pattern, and subjective effects in occasionally smoking adults Scientific Reports Full article: A review of e cigarettes and their effects on DNA methylation in human studies Nonnicotine vapes may be marketed as safe, but many still contain chemicals, have unknown health effects, and aren't FDAregulated. Teens are using them more ofteneven alongside nicotine vapes. No ecigarette is risk free. Nicotine Free Vapes Raise Concerns; Tests Reveal They're as Addictive as Full Strength E Cigarettes