TWIN FALLS, Idaho (KLIX) Idaho health officials are warning residents of the risks associated with high levels of radon gas that can be found in homes. According to the Idaho Department of Health and Welfare, radioactive radon gas is a naturally occurrence found all around the state, but is in higher concentrations in some areas. Usually in a natural setting radon is a minimal safety risk, however, over time the gas can build up inside homes and pose a serious safety hazard. In the 20 years of monitoring radon gas, IDHW says it has found that close to 40% of Idaho homes tested for radon have higher than recommended levels. Radon can only be detected with a special, inexpensive, testing kit; radon cannot be seen, tasted, or smelled. The gas enters homes through cracks in basements and crawl spaces. Radon can damage a person's lungs and is considered the second-leading cause of lung cancer in non-smokers. According to the Environmental Protection Agency, radon is blamed for 21,000 deaths each year in the Unite State. IDHW says Idahoans can buy radon test kits for a little under $10 and provided a resource page at that provides other resources. January is national Radon Action Month. Here is a map of areas where high concentrations of radon were tested.