doctors smoking cigarettes Doctor #1 by Adam Gault / Science Photo Library Real 'More Doctors Smoke Camels

This threat comes in many forms, but the most common include: Malfunctioning gas appliancesAny gas-burning appliance can emit CO if its not getting the correct gas-to-air ratio

Selye's Lasting Mark In the years since Selye's foundational work, research on stress has exploded

Even very small amounts of these materials can evaporate and form a flammable mixture in the air

Secondhand Smoke -- see more articles Find an Expert Children How Smoking Harms Your Child (National Cancer Institute, Tobacco Control Research Branch) Teenagers Secondhand Smoke (Nemours Foundation) Also in Spanish Patient Handouts Risks of tobacco (Medical Encyclopedia) Also in Spanish Smoking and asthma (Medical Encyclopedia) Also in Spanish Smoking and COPD (Medical Encyclopedia) Also in Spanish

It is often referred to as the "silent killer" because it is virtually undetectable by humans