The Pennsylvania Department of Environmental Protection is encouraging citizens to have their homes tested for radon. The message is part of the National Radon Action Month initiative, aimed at highlighting serious health risks high levels of the colorless, odorless gas can pose. Officials say radon is the second-leading cause of lung cancer in the United States, and roughly 40 percent of homes in Pennsylvania have levels that exceed U.S. EPA recommendations. DEP Secretary Jessica Shirley says radon test kits can be purchased from many home improvement stores for about 20 to 30 dollars.