There have been suggestions that granite countertops could emit radon gas. As with so many things, the answer depends on whom you ask. The Environmental Protection Agency "does not believe sufficient data exist to conclude that the types of granite commonly used in countertops are significantly increasing indoor radon levels." Read more about their position on this issue here. The Marble Institute of America says in a white paper  "that radon levels associated with natural stone countertops in homes are low in comparison to background levels of exposure and natural stone is a minor contributor compared to other sources of radon gas." Some environmental groups believe there may be a danger. See a discussion at Green Building Elements.

Foe more information visit: HOMEINSPECTORUSA