I have never heard of radon off gassing from Corian.
- Radon is a gas that is emitted form the ground and is only harmful in high concentrations in closed spaces like basements.
- Corian is a manufactured product that certainly off gases, but radon I would not think is one of them?
For more information:
Read Joel Hirshberg's terrific countertop Q&A "What's your opinion on Corian? I'm looking for a green and cost friendly countertop."