(WHTM) — January is radon action month, and the American Lung Association is reminding Pennsylvanians to test their homes for the gas.

Radon is a naturally occurring radioactive gas emitted from the ground that is odorless, tasteless, and colorless. It is the second leading cause of lung cancer and can enter homes through cracks in walls, basement floors, and foundations.

Get daily news, weather, breaking news and alerts straight to your inbox! Sign up for the abc27 newsletters here

“The only way to know what the radon level in your home or your school or your workplace is to do a test, and once high levels are confirmed it is a relatively simple solution to fix the problem,” Director of Environmental Health for the American Lung Association Kevin Stewart said.

Residents can find radon tests kits online or at local hardware stores. Radon is detected at high levels in almost 40% of homes.