Radon In Your Home - Studies Confirm the Safety of Granite Countertops - November 17th 2008





In recent months concerns about radon gas exposure within the home have surfaced, raising worries with many homeowners about whether their homes are posing a heath risk to their families.


About Radon

Radon is a colorless, odorless, radioactive gas that occurs naturally in the environment resulting from the natural breakdown of uranium in soil and rock.

A common element, Radon is found all over the globe in rock formations and soil containing uranium. In an outdoor or well ventilated environment, radon gas poses little threat to our health. However, in some confined spaces like basements, or dirt crawlspaces with poor ventilation, radon can accumulate to relatively high levels and become a potential health hazard. Radon molecules cannot penetrate human skin, but when inhaled will eventually lead to the deterioration of bronchial tissue, and cause lung cancer.

Faced with what Health Canada says was new evidence linking radon to lung cancer, understandably, there is a concern to keep any radon emissions in our homes to a minimum. Studies show that high radon levels are not widespread in Canadian homes. Some Canadian cities have been found to contain higher levels of radon in their soil than others. However, it is impossible to predict whether any one house will have a high level of radon without proper testing. Factors such as the location of the house and its relation to the prevailing wind may be just as important as the source of the radon.


Radon in Your Home

Radon gas can enter your home through the soil under your home, in dirt crawlspaces, through cracks in concrete, sumps, joints, basement drains, and cinder blocks. Radon trapped in water from wells can be released into the air when the water is used. Perhaps the most recent concerns regarding radon have risen from homeowners becoming aware of the radon content in granite surfaces within the home such as kitchen countertops, which have become very popular in higher end renovations and home upgrades.

Many people have become so worried of radon exposure from granite that they've taken it out of their homes completely. So recently on his radio program "The Home Discovery Show", Shell Busey interviewed Randy Ross, head of Radiation Protection Services branch at the BC Centre for Disease Control to find out the real story about granite and whether it poses a health threat in the home. Randy Ross has inspected over 100 varieties of granite, testing them for radiation using a Sodium Iodide detector. Many people believe that testing for radiation can be done efficiently with a Geiger counter, but as Randy explains "A Geiger Counter won't register as broad of a spectrum, or as accurately as a Sodium Iodide Detector".

The conclusion of his investigation was that none of the tested varieties of granite registered higher than 2-4 times that of background radiation levels. "That means that if someone were to lie on their counter for 12 hours per day, over a period of 365 consecutive days, they would almost reach the allowable public limit of radiation exposure" said Randy.

Granite surfaces in the home are also coated with a sealant, not only for durability and aesthetics, but also to inhibits radiation from escaping the surface of the product and into your home, in much the same way as sealing a concrete floor to stop moisture transfer.

It's to be noted that radon gas on any level will only build up in a relatively closed environment with little to no ventilation such as dirt crawlspaces or poorly vented basements with cracked concrete slabs. However if your home is well ventilated and air is constantly being exchanged, there should be little to no risk of a Radon problem.


Remedial Action

In British Columbia alone, only a few areas have been found to contain higher than normal levels of Radon. Prince George and surrounding area have some of the highest Radon levels found in B.C. yet only 1 percent of homes were found to have an indoor radon issue requiring urgent remedial action.

However if you have concerns about exposure to radon gas in your home, you might consider testing the level to see if it exceeds Canada's guideline for exposure to radon in indoor air. The guideline, which was updated in 2007, recommends that:

Remedial measures are taken in a dwelling whenever the average annual radon concentration in the normal occupancy area exceeds 200 Becquerels per cubic meter. The higher the radon concentration, the sooner remedial measures should be taken.

When remedial action is taken, the radon level should be reduced to a value as low as practicable (i.e., reduced as much as possible using methods that are cost-effective).

The construction of new dwellings should employ techniques that will minimize radon entry and will facilitate post-construction radon removal, should this subsequently prove necessary.


Radon Testing

Because there is some risk at any level, homeowners may want to reduce their exposure to radon, regardless of levels tested. Some of the steps you can take to reduce radon levels in your home include renovating existing basement floors (particularly earth floors), sealing cracks and openings in walls, floors, around pipes and drains, and ventilating the sub-floor of basement floors.

General Radon testing can be easily carried out by the homeowner using special detector kits or for in depth analysis, a technician can come to your home to do the testing for you. Radon testing kits do not test for radiation, and are available at local hardware stores or online.

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Radon Test Kits:

- Among radon test kits, Consumer Reports tested seven short-term kits, three long-term kits and a digital readout meter that can be used for either short or long-term measurements using experts at two outside labs. Among long-term kits (typically exposed for 90 days or more before lab analysis) Accustar Alpha Track Test Kit AT 100, $28, topped CR's ratings and is a CR Best Buy.  All three long-term kits, however, were very good.

While some were fine options, three short-term kits were especially inaccurate, unreliable, or both. The Accustar Short Term LS Radon Test Kit CLS 100i, $25, and the Kidde Radon Detection Kit 442020, $16, underreported radon levels by almost 40 percent. The Accustar Short Term Canister Radon Test Kit AC-1001, $30, was only "Fair" in accuracy and in reproducing the same result under the same conditions.

The full report is available in Consumer Reports by clicking here