New study comes the closest yet to proving that e cigarettes aren't as dangerous as smoking E cigarette flavors are toxic to white blood cells, warn scientists 5 Vaping Facts You Need to Know Johns Hopkins Medicine Health Effects of Vaping Smoking and Tobacco Use CDC Vaping Harmless. Vape aerosol contains toxic chemicals like formaldehyde, arsenic, lead, chromium, and nickel. They damage lungs. They harm developing brains. They raise cancer risks. We