August 2008 - I have been getting several calls asking for radon tests in homes with granite countertops based on recent publicly of the possible dangers of radon emission from granite products.
As a certified radon measurement provider, I can provide professional measurements or a specific placement plan to determine what your homes internal radon levels are. I can also provide real time Geiger Counter type measurements to locate problem areas with a non certified device if you feel a deep concern about the potential problem. The bottom line is there is not a large scale problem with granite and radon but it is possible to have a granite countertop with higher that expected emissions.
There are two problems to consider when dealing with granite countertops. First there is no protocol to determine what level of radon is acceptable and exact method of measuring it. Second measuring levels of radon in bathrooms or kitchens is not considered a preferred location in the measurement protocol due to potentially high levels of moisture and venting which may yield invalid results.
The EPA recommends that all homes be tested for radon in indoor air. Additional testing in homes with granite countertops could indicate if excessive levels of radon are present using a reasonable test approach.
Recommendations for using do-it-yourself radon testing:
Radon test kits can be purchased at hardware stores and online. Make sure they are fresh and use the same type for all your measurements. Purchase 3 to 4 test devices for this process. Black Dog Inspections can supply fresh professional quality test kits if you have difficulty in obtaining test devices.
1 Place one test in the basement or lowest area in the home to determine if radon is coming from the ground under your slab. (If a test was performed in the past, the measurements can be compared)
2 Place another test in a bedroom or family room at the same floor level as the kitchen or the room with granite countertops to establish a background radon level.
3 Place one or two tests in the room with granite countertops - put one on the granite surface and if necessary a second one the farther away on the counter for larger counter surfaces.
For the best results you should avoid using the room with the granite countertops (cooking, venting, and water use) since this may cause false readings during the test time.
Look at the results. The lower level test is usually 2 times the floor above. If there is a great difference between the counter top room and the non countertop room on the same floor level, the counters may be the contributors as long as the radon in water level has been determined not to be a contributor. If you are on public water or not on a deep well, radon in water should not be factor.
Remember passive test devices test for radon, not other radiation. If there is a large difference between the kitchen floor measurements, professional assistance may be your next step. If the test measurements are similar and much less than the lower level measurements, your counters are not a problem.
Names of qualified professionals who conduct radon and radiation testing can be located at www.aarst.org.
