E cigarettes: 'cancer risk close to zero' Bhekisisa Oral Health Risks of Vaping Secondhand smoke and aerosol 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. Scripps Health E cigarettes remain the most commonly used tobacco product among middle and high school students in the United States, according to the Instagram