FDA chief threatens to take e cigarettes off the market Structure of the electronic cigarette. The electronic cigarette is a Download Scientific Diagram Explainer: What are e cigarettes? E Cigarettes In recent years, the number of e cigarette users worldwide has sharply increased, with many believing that vaping is less harmful than smoking traditional cigarettes. However, health experts are warning of its negative All E Cigarettes Emit Harmful Chemicals, but Some Emit More Than Others Berkeley Lab Berkeley Lab News Center