No tobacco product is harmless according to CDC scientific evidence. E cigarette aerosol that users breathe from the device and exhale can contain harmful substances including heavy metals like lead, volatile organic compounds, E cigarette risk perceptions an American crime scene The Counterfactual Health Effects of E Cigarettes Kansas Health Institute The combination of propylene glycol and vegetable glycerin e cigarette aerosols induces airway inflammation and mucus hyperconcentration Scientific Reports Consider the Consequences of Vaping: