Allegations that granite countertops may emit dangerous levels of radon and radiation have been raised periodically over the past decade. Health physicists and radiation experts agree that most granite countertops emit radiation and radon at extremely low levels.
But with increasing regularity in recent months, the EPA has been receiving calls from radon inspectors and concerned homeowners about granite countertops with radiation measurements several times above background levels.
Personally I love the look and feel of natural granite countertops. Many people agree with me as they have become one of the most sought-after upgrades in residential housing over the last decade. And while most granite is perfectly harmless, most of the problems appear to be from some of the newer, more exotic varieties of granite.
I have had some major home renovation done in the last year, and have also moved into a brand new office building, so I actually became aware of this issue when I hired some Bau-Biology consultants to make sure we had a healthy office and home.
They pointed out to me that I needed to purchase a Geiger counter to measure the actual granite slab I was going to purchase, before I installed it. So I went through many hundreds of slabs to find ones that were low in radiation, and whose colors I found appealing.
Are Your Granite Countertops Dangerously Radioactive?
I believe it’s safe to say that not all granite emit dangerous levels of either radioactive radiation or radon, and you’re more likely to have high radon levels in your home due to radon in your water than due to your spiffy countertops. Luminous watches and smoke detectors are other sources of radon emissions that could be greater than that of your average granite countertop.
However, you won’t know unless you test them.
As described in this New York Times article, some countertops can measure at levels that are 100 times or more above the ambient radon levels. Especially troublesome are some of the more exotic granite varieties. Higher radon levels have been detected particularly in red, pink and purple granites.
However, you need to realize that even more important than radon are the radioactivity levels you’re continually exposed to in your home, some of which may be due to your granite countertops.
Below you will find more information on how to measure for both radioactivity and radon.
High-energy radiation, also known as radioactivity, comes in the form of alpha particles, beta particles, neutrons, gamma rays and X-rays. It has sufficient energy to knock off electrons to form ions; hence this process is called ionization.
When this type of radiation hits biological systems, such as your body, a cascade of chemical reactions is triggered.
Biological risks are also associated with small radiation doses through the accumulation effect over a long period of time. In fact, short but high radiation doses seem to be better tolerated by the human body than continuous but low radiation exposures.
Natural sources of radioactivity such as radium-226, thorium-232 and potassium-40 can accumulate in natural stones (and other building materials) depending on the originating mining area and production process. The specific activity of natural radionuclides varies substantially among different materials, but even within one type of material great dose variations can occur.
Among the building materials of natural origin, silicone-rich magmatic rocks - especially granite - show a relatively high content of natural radionuclides.
The purpose of bringing this to your attention is not necessarily to have you rip out your installed granite counters, unless they measure very high and you’re near for a large part of the day. The major reason for sharing this information is to allow you to measure any new slabs of granite you plan on installing.
As a side note, many smoke detectors are also radioactive in addition to emitting radon, as they are based on ionization. A better option is to use a photoelectric smoke detector in your home.
Other sources that are oftentimes high in radioactivity and should be tested include:
- Waste products used in gypsum
- Basaltic rock
How To Use a Geiger Counter to Measure Radiation
The easiest way to measure your countertops and other building materials for radiation is to use a handheld Geiger counter.
Geiger counters measure alpha, beta and gamma radiation, but not radon.
The Geiger counter's sensor is a central metal wire anode surrounded by a thin metal tube filled with neon, argon and a halogen gas. It detects radiation by how much the gas inside the tube is ionized.
They range in price from $150-400 and can be found easily online. Even Amazon.com carries them.
Here’s a simple step-by-step process on how to use your Geiger counter:
- Turn on your Geiger counter to apply an electrical charge to the anode wire. The counter will click or flash about 10 to 20 times per minute as it detects background radiation.
- Pass the sensor, called a Geiger-Mueller tube, over your granite countertop (or any other material you want to evaluate) with the thin mica window facing the material. Radiation from the material, if any, will pass through the window and ionize the gas inside the tube.
- Study the readout, whether a needled meter, flashing LED, or audible clicking. If this is higher than the level of the background radiation, then the material is radioactive.
- Count the number of clicks or flashes, or read the attached meter, to determine how radioactive your material is.
Geiger counters cannot accurately measure the presence of radon gas, specifically. To measure radon, you’ll need a radon detector. However, using a Geiger counter to check for radioactive radiation is a much easier and convenient way to ensure that your granite slabs are safe.
What is Radon?
Radon is a cancer-causing natural radioactive gas that you can’t see, smell or taste. The amount of radon in the air is measured in "picoCuries per liter of air," or pCi/L.
About 0.4 pCi/L of radon is normally found in the outside air, and the average indoor radon level is estimated to be about 1.3 pCi/L.
According to the EPA, you should take action any time the radon level in your home (or office, for that matter) is at or above 4 pCi/L, which carries about the same risk for lung cancer as smoking half a pack of cigarettes per day.
This does not necessarily mean that 4pCi/L is “safe,” however, just as “only” smoking half a pack a day cannot be considered “safe.”
There really is NO safe level for radiation. Even the EPA admits that lower levels can still pose a health risk, and you may want to take precautions to further reduce the amount of radon in your indoor space, even if it’s at or below 4 pCi/L.
Radon Causes Lung Cancer – How to Evaluate Your Risk
Radon is the second-leading cause of lung cancer after smoking in America, and the leading cause of lung cancer among non-smokers, claiming about 20,000 lives annually, according to EPA statistics.
Your chances of getting lung cancer from radon depend mostly on:
- The level of radon in your home
- The amount of time you spend in your home
- Whether you are a smoker or have ever smoked
Logically, smokers are far worse off when it comes to radon raising their lung cancer risk as their lungs are already compromised. Children and developing fetuses are also especially vulnerable to radiation, as it can cause other forms of cancer as well.
According to the EPA, if 1,000 smokers were exposed to the “action” radon level of 4 pCi/L over a lifetime, about 62 of them would get lung cancer from the radiation, compared to only about 7 out of 1,000 non-smokers.
How to Test For Radon
Testing your home for radon is also a simple process, if you want to check for radon specifically -- although you're likely better off just testing for radioactive radiation with a Geiger counter.
There are many low-cost do-it-yourself test kits available, averaging in price from $20 to $30. You can purchase them online at the EPA’s Web site www.epa.gov/radon, from your regional indoor air environment office, or in your local hardware store.
You can also hire a professional to do it for you, which may be a better option if you’re buying or selling a home. If you decide to go that route, contact your state radon office first to obtain a list of qualified testers.
Alternatively, you can contact a private radon proficiency program, or the American Association of Radon Scientists and Technologists, for lists of privately certified radon professionals in your local area.
For more information on how to ensure your home supports rather than harms your health, and how the principles of Bau-Biologie (building biology) can help, please see my Related Articles below.