It’s colorless and odorless. But it could be in your home and causing lung cancer. The invisible threat is radon.

A naturally occurring gas that seeps out of rock and soil, radon can enter houses through the slightest of cracks or openings in the ground level of a structure. Radon alpha particles attach to dust or smoke and when inhaled can penetrate the mucus membranes of the lungs, causing cell damage that can lead to cancer, said Becky Chenhall, one of five radon educators at the University of Georgia.