Here's a new addition to the already known and harmful active and passive smokers category. Till now we were aware of the hazards of passive smoking (second-hand smoke) that folks in vicinity of smokers suffered. However now we need to steer clear of the "third-hand smoke" too. It is defined as the invisible yet toxic brew of gases and particles clinging to smokers' hair, clothing, cushions and carpet that lingers long after second-hand smoke has cleared from a room. This residue includes heavy metals, carcinogens and even radioactive materials that young children can get on their hands and ingest, especially if they're crawling or playing on the floor.

Doctors from MassGeneral Hospital for Children in Boston coined the term "third-hand smoke" to describe these chemicals in a new study that focused on the risks they pose to infants and children. Simply closing the kitchen door to take a smoke is not enough to protect the kids from the effects of that smoke. There are carcinogens in this third-hand smoke, and they are a cancer risk for anybody of any age who comes into contact with them.

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