I have seen a few articles recently about possible dangers in granite counters. Depending on where the granite was sourced, it may contain very high levels of radon or radioactivity (which can cause cancer and is especially dangerous to children or pregnant women).
I think a recent article in the New York Times was very thorough in explaining the risks and putting the problem in perspective. From what I understand, most counters are safe but there are some varieties that have levels of radon much higher than recommended. Some experts say that it is still a very small amount, but others say any risk may be too much.
For more information or to find out how to test your granite counter tops the New York Times reports,
" homeowners can contact the American Association of Radon Scientists and Technologists (aarst.org). Testing costs between $100 and $300. Information on certified technicians and do-it-yourself radon testing kits is available from the Environmental Protection Agency’s Web site at epa.gov/radon, as well as from state or regional indoor air environment offices, which can be found at epa.gov/iaq/whereyoulive.html. Kits test for radon, not radiation, and cost $20 to $30. They are sold at hardware stores and online."