Radon is a colourless, odorless radioactive gas released as uranium breaks down in the soil. It causes cancer, especially of the liver, and is increasingly a problem for homeowners across the United States. The gas seeps in between cement basement or foundation slabs and is trapped in the house. Radon leaks are detected by blowing small puffs of smoke along cracks inside the foundation of homes. If the smoke blows away from the crack, radon as leaking into the home is usually indicated. Radon detectors are then utilized to determine that radon is present. Once a home is diagnosed with radon leaks, efforts are focused on safely getting the radon out of the house with a minimum of exposure to the homeowners. The diagram above is from J. Babb's website at www.jbabb.com. Mr. Babb is an electrician and home repair specialist, while his wife focuses on indoor air quality. The system shown uses roof fans to suck gas out of the basement and disperse it above the home. This creates a steady flow of air up and out of the house, rendering it safe.