Vaping has become common, but it's important to know what you're inhaling. Many e cigarettes contain nicotine, heavy metals like nickel and lead, and chemicals that can harm your lungs and overall health. Toxicological Effects of E Cigarettes on Cells, Animals, and Humans and Mechanisms of Toxicity Springer Nature Link e cigarettes HSE Health and Wellbeing The Effects of Vaping on Oral Health Johns Hopkins Medicine Team Proposes Ways to Regulate and Better Manage E Cigarette Use Johns Hopkins Medicine Infographic: Dangers of E cigarettes & Toxicity UPMC HealthBeat