Iowa has one of the highest concentrations of Radon gas in the country, and even for Iowa, Washington County has a high concentration. The national average for Radon concentration is 1.3 picocuries per liter. Washington County’s average concentration, as well as Keokuk County’s, is 6.8 picocuries per liter. The reason for Iowa’s high levels is geologic activity millions of years ago. Mike Hendrickson with Inspect First Home Inspections says radon can cause lung cancer. In fact, radon gas is the leading cause of lung cancer for non-smokers according to the Surgeon General. He says radon effects all homes equally. It doesn’t matter if you have a new home or an old one. He recommends getting a radon testing kit to check your home. He also says that not all cities in Iowa require that homes be tested when they are bought and sold, although some groups in Iowa, including the American Cancer Society, are pushing the state legislature to require that homes be tested.