January is national Radon Action Month. Radon is an odorless, colorless radioactive gas that occurs naturally from the breakdown of uranium in soil and rocks, and enters homes through cracks in the foundation or other openings. An estimated 40% of Pennsylvania homes have higher levels of radon than national safety standards. You can perform a simple test to detect the gas, which is considered the second leading cause of lung cancer. High levels of radon tend to be found in basements, but the gas can be found anywhere in the home. Winter is a good time to test, because doors and windows are generally closed, providing more accurate results. Simple radon test kits are inexpensive and available at home improvement and hardware stores.