A new report published in the new york times is warning homeowners that their granite countertops could be a health hazard.

Some exotic varieties of granite, especially from Brazil and Namibia, have been found to emit hazardous levels of radon, a radioactive gas which can cause lung cancer. The Marble Institute of America says granite is known to contain small amounts of radioactive materials, but that the amounts contained in countertops are not enough to pose a health risk.

So what can you do if you have granite counters? The EPA says concerned homeowners can hire someone to test their countertops, or purchase a radon test kit at a hardware store.