Unfortunately, the short answer is yes. In fact, it’s the leading cause of cancer for nonsmokers in the United States. For smokers, radon comes in second and contributes to an already-dangerous health situation. Radon comes from the soil as uranium breaks down in nature. Found everywhere in the world, radon levels can vary depending on the geographical location in which you live. You can’t see, smell, or taste radon, which makes it impossible to detect without a radon test.