Do granite countertops pose a radon threat? The evidence is mixed. Radon, a colorless and odorless gas, is the second leading cause of lung cancer. Granite can be one source of radon emissions in the home; the gas occurs naturally in the rock formations and leaches out once it is installed in your kitchen. Tests show that radon levels in granite rock can vary immensely, from hardly detectable at all to possibly dangerous. While some sources have suggested that red or black-veined granite may be more prone to radon emissions, there's no hard evidence that this is so. Similarly, there's no definite link between the source of the granite and its radon levels.

On the Other: An Alternative to Granite

Since there's no way to determine your granite countertop's radon emission levels short of testing before purchase, perhaps you'd like to consider an alternative material: crushed quartz. Crushed quartz countertops are as durable and scratch- and heat-resistant as solid granite; because they are a composite of crushed stone and resin rather than one solid slab of stone, they are also a little easier to handle.

Bottom Line

Whether you decide to be concerned about the radon levels of your granite countertop or not, one thing is certain: you cannot tell from the color what the likely levels of radon emissions might be. Radon levels vary from source to source, and even from slab to slab. The only way to be sure is to have it tested. If you're seeking a radon-free alternative, look into crushed quartz. Crushed quartz looks like natural stone, and the cost per square foot ($50 to $90 as of January 2010) is comparable to solid granite.

Source:

Consumer Reports Home & Garden Blog: Buzzword:Radon

WCCO.com: Radon in Granite Countertops?

Radon.com: Granite and Radon