Lately, we have had several people asking about radon and radiation emissions from natural stone, and since this has been a 'hot' topic in the stone business for many years, we wanted to provide you with some information so you can choose the right material for your home.
The Marble Institute of America has completed abundant studies, carried out by independent institutions like the Environmental Health & Engineering, Inc., to provide 'neutral' true facts and put an end to misleading information that competing material organizations are continuously divulging. Some of this information has suggested that granite can emit levels of radon or radiation that pose a health threat. But before getting into too many details, let's start from the basic...
Even though they may sound alike, radon and radiation are not the same thing. So what is the actual difference between the two?
Radon, produced from radium, is a radioactive gas that occurs naturally in the environment. It is commonly found in the basement of homes in most of the US, and the United States Environmental Protection Agency (EPA) says that by far the primary source of radon in any home is the soil surround it.
On the other hand, radiation, are particles emitted by radioactive substances, and one of the primary sources of radiation in our environment is the sun.
Just by reading the above descriptions, the first thing that comes to my mind is … ‘they are everywhere’ and in fact radon and radiation are then in the air we breath, in the water we drink, in the soil and rock we stand on, and in the sun’s rays, but let’s take a look at some actual facts from the following graphics to get a visual idea of where we can find radon.
As the chart indicates, almost 70 percent of radon results from soil around the house, and just 2.5 percent from all building material (such as concrete, brick, gypsum, and natural stone) used in the house. This might surprise some of you, but actually not the people that have been working for years in the natural stone business. Unfortunately, as I mentioned before, a lot of the information found online about radon, radiation and natural stone have been purposely used by manufacturers of competitors’ materials to hit granite popularity, so before you take into account any information make sure it is from an authentic resource.
But let’s get into the actual ‘scientific analysis.’ The EH&E designed and carried out a series of experimental studies required to characterize radon and radiation exposure and risk quantitatively.
These comprehensive studies conducted in a scientific valid manner were designed to see weather granite or marble countertops can SIGNIFICANTLY increase exposure and doses of radon and radiation in our homes. The in-depth analysis focused on risk of exposure to radon gas and ionizing radiation associated with the majority types of natural stone used as countertops in United States. In these studies the testing protocol included:
i) Determine pertinent gamma activity concentrations
ii) Measuring total alpha, beta, and gamma emissions
iii) Measuring total external radiation doses
iv) Determining radon flux from a wide range of representative stones
To characterize potential radiation risks of natural stone countertops, the estimates of doses were compared to a variety of health-based benchmarks for radon and radiation safety by authoritative organizations such as National Council on Radiation Protection and Measurement (NCRP). Over 400 samples from 115 varieties of stone were evaluated, and the results indicated that:
- Radon emission test results combined with the market share data indicate that the average predicted contribution to indoor radon from all stones tested is less than 0.01 picocuries per liter (pCi L-1), a concentration that is well below both the average outdoor radon concentration in the United State of 0.4 pCi L-1 and the U.S. Environmental Protection Agency guideline for remedial activities to be undertaken of 4.0 pCi L-1.
- External dose associated with radiation emissions for all of the slabs tested are well below health-protective guidelines, including the exemption limit of 0.3 mSv per year recommended by the European Commission. The United States has yet to establish an exemption level for building products based on radioactivity to our knowledge.
- Assessing exposure to radon and radiation requires accounting for duration and frequency of exposure, not just absolute magnitude. In addition, measurements must account for variability of the countertop surface. Ventilation is accounted when estimating radon concentration in indoor air, while for radiation, distance and geometry must be incorporated in the assessments.
- Significant variability was observed across stone types.
For further information and table data you can check out the full report on the study “Assessing exposure to radon and radiation from granite countertops” at http://www.eheinc.com/documents/EH&E.GraniteCountertops.UpdatedReport.pdf
In summary, the intense laboratory testing conducted by the EH&H revealed that natural stone, in particular granite (since for Americans ‘nothing beats the beauty, and value of granite countertops’), is an ‘insignificant’ source of radon and that 99.5% of granite countertops produce less radon than what’s found outdoors. Also, further studies have shown that there is ‘no risk’ of dangerous levels of radon in granite.
Therefore, there is NOTHING to be concerned about!
As Dr. Joseph Allen, head of the EH&H, said “The most typical granite countertop installations would produce a radon concentration in the home that is 10,000 times lower than the EPA action level, and are so low they are not even measurable.”
In other words, we’re probably at a higher risk standing in front of the microwave waiting for our tea or coffee to warm up … it is sad to say but VERY MUCH TRUE!
And if we really think about it, there are so many 'other things' that we should be concerned as a health risk in our homes ... like the loaded fluoride and bleached water we use everyday, and the additives, and preservatives in our food or house cleaning supplies?? What about those??!!??
Something to REALLY think about ...