Study shows second hand vaping exposure very low compared to second hand smoking E Cigs and Second Hand Vaping: Dangers and Protections According to a Centers for Disease Control and Prevention (CDC) study, 40% of U.S. adults believe that children's exposure to secondhand aerosol from e cigarettes causes only some or little harm, and 5% According to the American Heart Association, the risks of secondhand smoke from vapes are still being discovered. Learn about the dangers of secondhand smoke from vapes.