Is ‘Juuling’ safe? What’s really inside the popular e-cigarette

The debate about e-cigarettes is reaching a boiling point, with the FDA saying this week it has “hard data to support that a public health tragedy is now underway.” NBC senior investigative and legal correspondent Cynthia McFadden does a deep diver into the science behind them, particularly the biggest e-cigarette maker, Juul, and a leading scientist’s study.