Radon is a colorless, odorless gas that can cause cancer -- in fact, it is the second leading cause of lung cancer after cigarette smoking!  Radon quickly disperses in air, reducing its danger, but if it accumulates in a basement or other living space, it can be quite problematic. 

One of the main sources of radon gas is from a variety of types of rock, such as granite and shale.  And thus, people have begun to wonder whether granite counter tops might pose a risk!

Well, in what may put your mind at ease, the Marble Institute of America released a report a few days ago (Nov 17, 2008) indicating among other things that "not one stone slab contributed to radon levels that even reached theaverage U.S. outdoor radon concentration of 0.4 picocuries per liter."

If you're eying your granite counter tops warily from across the room, and need to be further reassured, read more from Nation's Building News.