How are people exposed? Thirdhand Smoke Resource Center 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 How secondhand smoke, thirdhand smoke & vaping affects kids Breathing in someone else's smoke or vape isn't harmless. Secondhand smoke exposure can affect your lungs, brain, and overall health. Protect your families and yourself. Inhalar el humo o el vapor de Does Vaping Cause Secondhand Smoke?