Vaping is often marketed as a safer alternative to smoking, but many vape products contain nicotine, harmful chemicals, and heavy metals that can harm developing brains and lungs. Eliminating Tobacco Use in Washington Kids American Heart Association Does Vaping Cause Lung Cancer? What We Know (and Still Don't) Composition of electronic cigarette aerosol Wikipedia Do you really know what's in your vape? There's no safe vape. Besides nicotine, vapes contain many other harmful substances. Formaldehyde, arsenic and lead have all been found inside common vapes.