Radon is a naturally occurring, radioactive gas formed by the breakdown of uranium. Radon is tasteless, colorless, and odorless, and is found in many types of soil and rock. It can enter homes through cracks in foundations, sump pump crocks, crawl spaces, or other openings. Radon is present in outdoor air, but is diluted to such low levels that it is usually not a concern. However, inside an enclosed space (such as a home), radon can build up to dangerous levels. Any home can have a radon problem -- new and old homes, well-sealed and drafty homes, and homes with or without basements.