Radon gas occurs as radiation decays. In areas of the country that have elevated levels of naturally-occurring radiation from the minerals in the soil, it is not uncommon for radon gas to be present in homes and other buildings. If a radon test of a home shows levels of radon above the EPA action level, the radon can be easily and inexpensively mitigated during or after construction.
Most homes on previously-mined lands in Florida will be below the EPA action level for radon in air, but a higher percentage may be above the action level when compared to unmined land over phosphate deposits. Radon concentration in a home largely depends on construction practices, and radon is easily and inexpensively mitigated during or after construction.