While cigarette smoking is still the number one cause of lung cancer in the United States, the runner-up in the category could lurk in your home. January is Radon Awareness Month recognizing the deadly, radioactive gas that is naturally in the ground and enters buildings through the foundation. At an estimated 21,000 lung cancer deaths per year, radon causes more cases of the disease among non-smokers than second-hand smoke. Five to ten percent of homes in Wisconsin have elevated radon levels on the main floor. Radon levels can vary from county to county and even neighborhood to neighborhood. In Kewaunee County, the average radon level is 6.2 pCi/L (picocuries per liter), and in Door County, it is 5.1 pCi/L. Both are above the national average of 1.3 pCi/L, and over the  2.0 to 4.0 pCi/L, the Environmental Protection Agency recommends Americans install a radon mitigation device. The Kewaunee County Health Department encourages residents to purchase a short-term test kit to make sure there are safe from the harmful effects of radon. The tests are available for $8 from the Kewaunee County Health Department.