The Marble Institute of American has announced the conclusion of a recently conducted scientific study of thirteen of the most popular granites used for kitchen countertops in the United States during 2007. The study confirms that granite is a safe material for use in kitchens.

The issue of granite containing radon has surfaced repeatedly over the years. The origins of these concerns are advertisements and other communications from the manufacturers of radon detection devices and the manufacturers of competing synthetic countertop materials. Each time these concerns have arisen, the Marble Institute of America, as well as several producing companies, has responded by thoroughly researching the issue to determine if potential health hazards actually exist.

MIA's most recent testing was 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 granite types are as follows:

  • New Venetian Gold
  • Brazil; medium grained, yellow-beige gneiss with many dark red garnets.

  • Uba Tuba
  • Brazil; A medium- to coarse grained, olive-green granite.

  • Santa Cecilia
  • Brazil; A coarse-grained, yellow-grey gneiss with up to pie-sized, red garnets.

  • Tropic Brown
  • India; A black-brown igneous rock with big, shapeless, brown-red feldspar crystals.

  • Giallo Ornamental
  • Brazil; coarse-grained, brown-yellow granulite with some brown-red garnets.

  • 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.

  • Baltic Brown
  • Finland; brown-black granite.

  • Giallo Veneziano
  • Brazil; medium- to coarse-grained, ochre-yellow to golden-brown, also light pink, gneiss.

  • Dakota Mahogany
  • USA; medium- to coarse-grained, brown-red granite.

  • China Black
  • China, a fine-grained plutonic rock.

  • 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 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. Tropic Brown and Baltic Brown, second and third in radon emanation based upon Dr. Chyi's testing, amounted to only 1% of this action level. The other granites tested added almost immeasurable amounts of radon to the house.

Dr. Chyi's test results show that the granites that are currently found in the United States' market place are insignificant contributors to radon levels in the home. Based on the testing results and EPA standards, we can conclude that the most popular granites used as countertop surfaces pose no health threat to homeowners. The test results are available on MIA's website.

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