About Electronic Cigarettes (E Cigarettes) Smoking and Tobacco Use CDC What's Actually in Your Vape: A Complete Chemical Breakdown High concentrations of flavor chemicals are present in electronic cigarette refill fluids Scientific Reports The more you know, the safer the choices you can make. E cigarettes and vape pens are not harmless. Many contain nicotine and other chemicals that can impact brain development, lung health, Electronic Cigarette Use, Misuse, and Harm Medical Clinics