Dynamic Chemistry and Toxicity of E Cigarette Aerosols and Their Product Waste Chemical Research in Toxicology What's the difference between PG and VG? Toxicity of the main electronic cigarette components, propylene glycol, glycerin, and nicotine, in Sprague Dawley rats in a 90 day OECD inhalation study complemented by molecular endpoints Have you ever breathed in secondhand vapor from a vape? What exactly are you inhaling? It turns out it's a lengthy list of chemicals. FULL STORY