Radon is a naturally occurring gas found in soil, rocks, and water throughout California and the world. Radon has no color, odor, or taste. Radon gas entering homes, schools, and other buildings from the ground is our largest exposure to naturally occurring radiation.
The California Department of Conservation has geographic information and maps of indoor radon potential for different areas in the state
Radon leaks inside buildings through cracks and holes in the slab or foundation or can come through the water supply. Air pressure in the ground is usually higher than inside buildings, so the outside pressure pushes radon gas through small openings in a building’s structure. The health effects of radon stem from radiation-induced cancer.
More information about radon can be found at the links below:
CDPH Indoor Radon Program and Interactive Radon Potential Map
US EPA Information on Radon, Radon Action Plans, and Radon Programs & Initiatives