Radioactive granite?

I wonder how common this is? (vs. just somebody trying to profit on fear)

http://www.nytimes.com/2008/07/24/garden/24granite.html?_r=3&pagewanted=2&sq=What%27s%20Lurking%20in%20Your%20Countertop&st=cse&scp=1&oref=slogin