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If you have granite countertops in your home, you should consider having them tested for the amount of radon gas they emit just to be sure of any potential danger.

• Radon remains the second leading cause of lung cancer in the country.



• 1 in 15 homes tested have dangerous levels of the cancer-causing radioactive gas.

Watch a CBS segment on Radon in Countertops

Expert calculations demonstrate that an average kitchen countertop contains an average uranium concentration of four ppm (parts per million), the concentration of radon that is given off by the countertop into the household air would be 270,000 times less than the level of radon in the outside air. The maximum contact level that you would receive over one year if you were to sit on a countertop all of the time would be about one quarter of the annual radiation from all sources. If you were just a few inches away from the granite (such as when doing the dishes), the dose would be too low to measure.

Donald Langmuir, PhD, Professor Emeritus of Geochemistry, Colorado School of Mines, & President of Hydrochem Systems Corp. states: "To show how laughable the concerns are of radon emitted from natural stone, the typical granite countertop in our example will release 7.4 x 10 -7 pCi/L of air. This corresponds to 2.7 x 10 -8 atom decays per second (dps). This represents 0.85 decays per year. In other words, less than one atom of radon is produced by the countertop in one year. This is hardly worth getting excited about".

Radon Testing of Various Countertop Materials Final Report

In a recent study conducted by L. L. Chyi, a Ph.D. and professor of Geochemistry and Environmental Geology at The University of Akron, Akron, Ohio. Dr. Chyi studied 13 of the most popular granites used throughout the United States as determined by an industry-wide survey. Due to their popularity these 13 granites, are believed to represent up to 85% of the granite countertop market in recent years.

The specific granite types are as follows:

1. New Venetian Gold, Brazil; medium grained, yellow-beige gneiss with many dark red garnets
2. Uba Tuba, Brazil; A medium- to coarse grained, olive-green granite
3. Santa Cecilia, Brazil; A coarse-grained, yellow-grey gneiss with up to pie-sized, red garnets
4. Tropic Brown, Saudi Arabia; medium-grained, brown granite
5. Absolute Black, India; black basalt
6. Tan Brown, India; A black-brown igneous rock with big, shapeless, brown-red feldspar crystals
7. Giallo Ornamental, Brazil; coarse-grained, brown-yellow granulite with some brown-red garnets
8. Crema Bordeaux, Brazil; Juparana Crema Bordeaux, Brunello; A coarse- to very coarse-grained, pink to red granite with areas of quartz, alkali feldspar and quite a lot of ore
9. Baltic Brown, Finland; brown-black granite
10. Giallo Veneziano, Brazil; medium- to coarse-grained, ochre-yellow to golden-brown, also light pink, gneiss
11. Dakota Mahogany, USA; medium- to coarse-grained, brown-red granite
12. China Black, China, a fine-grained plutonic rock
13. Yellow Star, China, a medium-grained yellow to pink granite

The testing methodology was designed to measure the amount of radon which each granite type would add to the interior of a 2,000 square foot, normally ventilated home with 8 ft ceilings. The results show that # 8, Crema Bordeaux (the most active in terms of radon emissions) would contribute a concentration component of less than 0.28 pCi/L, or less than 7% of the EPA's recommended actionable level of 4.0 pCi/L. This radon amount is well below a level which might cause health concerns.

Typical Contributions to Radon Content of Indoor Air (pCi/L)

In Conclusion:

After carefully looking into this issue, the amount of Radon emitted by commercially available granite countertops is not a serious threat to homeowners. It should be noted however, that not all research data confirms these levels to be consistent, and homeowners should still have their home and countertops tested for unsafe levels of radon by a professional Radon tester. After all, you should be aware of the amount of Radon present on your home.