What Happens When You Quit Smoking and Start Vaping? 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. E cigarette or Vaping Use Associated Lung Injury (EVALI) The Essentials Vaping Information, Solutions & Interventions Toolkit Stanford Medicine