The production of radon, its entry and accumulation in a building involves the following:
- Radon is produced by the nuclear decay of uranium found in rocks and soil.
- Radon naturally diffuses up through the ground.
- Radon enters through pinholes and cracks in the foundation.
- Radon gas dissolved in water is released through agitation (in bathrooms for example).
- Insulation, modern windows, and modern building materials keep radon from escaping.