Thousands of Unknown Chemicals Found in E Cigarettes Respiratory Therapy 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. Toxicity of electronic cigarettes: A general review of the origins, health hazards, and toxicity mechanisms ScienceDirect About E Cigarettes (Vapes) Smoking and Tobacco Use CDC