Debunking 7 Myths About Secondhand Smoke Ever puffed a vape around others thinking it's harmless? Think again. Inhaling vapor from e cigarettes exposes you to harmful chemicals, such as formaldehyde. These toxic substances can be passed on to Is Second Hand Vape Smoke Dangerous? RxLeaf Secondhand e cigarette vape smoke exposure increased in last 4 years, contain harmful toxins: JAMA Network study ABC7 Chicago Is Vaping Better Than Smoking? American Heart Association Secondhand vape plumes could form lung damaging radicals American Chemical Society