Granite is radioactive, but how much so?

Over the years granite countertops have become a huge selling point for homes, often adding thousands of dollars to the listing price and value of a home. But over the last couple of years, many people have begun to sound the alarm about the possible amounts of radiation homeowners can be exposed to.

Before we talk about the possible dangers, let’s put on our geology hats and learn more about granite; this is important to understand why people are concerned about it. Granite is an igneous rock, formed by heat and pressure deep within the earth. After millions or billions of years, eventually gets squeezed up towards the earth’s surface where it can be mined. The earth’s core and deeper levels are filled with radiation, and being formed in those depths, granite is exposed to and absorbs it.

Now we need our chemistry hats. As granite forms it is exposed to uranium, which is used for nuclear power plants and bombs, so you know it’s dangerous. As uranium degrades it releases a gas called radon. Radon is considered a carcinogen and has been linked to lung cancer and several other forms of cancer. Radon is all around us, the dirt our homes are built on or in contains it and the air is filled with it as well, we can’t escape it. Usually radon is found in homes in basements, where the dirt that contains it surrounds it.

Most granite countertops radiate 4 picocuries of radiation per day, which is about as much as we come into contact with on a daily basis. There have been reports of some granite radiating 100 picocuries per day, which is on the dangerous side.

But all of this talk of “danger” deals with how much time you spend at your counters. If you live around them and spend a lot of time, then feel free to have them tested for radon levels. But mostly, you shouldn’t worry. The amount of radon you are exposed to over a year is equal to smoking half a pack of cigarettes.

Is there a danger? Only if you spend every minute of your 24 hour day living on your granite countertops. Even then, the “danger” is minimal. Your best bet? Just leave them in and not worry.