Radon is a colorless, odorless, cancer-causing radioactive gas. It forms naturally from the decay (breaking down) of radioactive elements, such as uranium, which are found in different amounts in soil and rock throughout the world. Radon gas in the soil and rock can move into the air and into underground water and surface water. In many parts of the country, radon emanates from concrete so can be especially prevalent in condos. Radon can also move from the ground to upper floors of condos via elevator shafts and stairwells. This causes troublesome problems for condo owners and associations.
To put your mind at ease, radon gas is generally not a problem for most of Hawaii for a few reasons. The uranium content of Hawaiian rocks is low. Most of rocks near the surface in Hawaii are relatively porous. Homes and condos in Hawaii are typically well-ventilated. Without a lengthy scientific explanation, these are the key reasons it is difficult to find high levels of radon for most locales in Hawaii.
This doesn’t mean, however, that elevated levels can’t occur here. Don Thomas, a University of Hawaii researcher who specializes in environmental radon measurements, reports that elevated radon does occur in the groundwater of some areas on the older Hawaiian islands (Kauai and Oahu) but even this is not high enough to accumulate in homes to dangerous levels. Even in radon enriched geothermal waters, like those near the volcano on the Big Island, the groundwater remains relatively normal. This is because the permeability of the subsurface rocks on the rift zone are so much higher than the soils here, allowing air infiltration and exchange to dilute the radon.