Radon is natural radioactive gas that is colorless, odorless and tasteless. It comes from the natural decay of uranium in rock, soil and water and is found in nearly all soils. As it moves up through the ground to the air above, and creeps into your home, offices, and schools through cracks and other openings in the foundation. Radon gas decays into radioactive particles that can get trapped into your lungs every time you take a breath.

KCBS News Desk

Re: Recent Interest (panic) in Radon Found in Granite (yes, counter tops), and Marble Floors


July 28, 2008: A July 2008 article in the New York Times (Reprint of PDF Here) has created considerable radon concern in individuals who are enjoying the beauty of natural stone, marble and granite in their homes.

The potential for radon in natural materials is not a new story. The EPA’s “Consumer’s Guide to Radon Reduction” chapter “How Radon Enters Your House” states:

"In a number of small homes, the building materials (e.g., granite and certain concrete products) can give off radon, although building materials rarely cause radon problems by themselves. In the United States, radon gas in soils is the principal source of elevated radon levels in homes."

It is true, however, that SOMETIMES (as in the NYT article) a granite surface can be the source of radon, and the only way to know is to test for it!


How The Radon Lady Tests for Radon in Granite (and other natural stones) PDF Printable Version Here

To evaluate potential radon of a room with granitic material, start by comparing radon test results from the granite-containing areas versus same floor level rooms without the granite.

Most radon comes into homes from the ground. If your granite containing room is not on the lowest level of the home, get an additional kit or two and also test at the lowest used level as recommended.

Short term radon tests available for consumers require 3-7 days of testing in “closed house conditions.” This means that the doors, windows and other air-flow locations are closed for 12 hours prior and 3-7 days during the testing period. If there is more than one level to the house, all levels must be closed. Normal entry and exit is permitted, but the air conditioning system should be on re-circulation with no air coming from outside.

Tip from the Short Term Kit Manufacturer:

If are testing in the kitchen, eat out for a few days, because the fluctuations in temperature from cooking could you alter the results.

When the results come back, if the radon levels in the granite containing room is higher than the non granite rooms, you may have a problem. Follow-up actions will depend on the actual results.

Since the short term tests are forced “worst case” conditions, it is prudent to also perform long-term (Alpha Track) testing in the same areas. Long term testing does not have any special requirements or conditions except that the monitor is left in place for 90-364 days. A long term monitor that is in place for one “open window” and one “closed window” season will give a more realistic picture of radon levels in actual living conditions.

Test kits from an approved laboratory are available through a link at

Summary of suggested test kits:

  • 1 Short Term test kit for each room with granite, marble or other natural stone
  • 1 or more Short Term test kits for another non-granite room on the same floor/level of the house
  • 1 or more Short Term test kits for room or rooms at the lowest lived-in floor of the house
  • 1 Long Term (Alpha Track) test kit for each granite/stone containing in the house
  • 1 Long Term (Alpha Track) test kit for another room at the same level for comparison of the results of the room containing granite or stone
  • 1 Long Term (Alpha Track) test kit for the lowest livable area of the house, if it is not one of the above

If testing is performed for a real estate transaction, a professional is required. Homeowners are encouraged to check their own homes, even if they don’t have granite or stone. Radon, which as discovered only in 1983, is the second cause of lung cancer after cigarette smoking. It is responsible for more deaths than drunk drivers. Every year the number of people who die from radon related lung cancer is equal to having a 747 crash each week at SFO. That’s a lot of deaths that can be avoided with simple and relatively inexpensive testing.

Bonnie Lee Kellogg, The Radon Lady, is a licensed professional radon, asbestos, lead and hazardous materials consultant. She is Director of KELLCO-MACS, a Bay Area based hazardous materials consulting company and laboratory.

Press Release

Radon gas kills more people a year than drunk drivers, and yet most Americans are unaware of its presence and its danger. Bonnie Kellogg, The Radon Lady, is embarking on a campaign to change that.


Hayward, CA November 1, 2007:  Radon is an inert gas that comes from below the earth’s surface.  It is a by-product of Uranium, and is found all over the world. It is the second greatest cause of lung cancer after smoking and causes more deaths per year than drunk drivers.

When it comes to Radon, the general population falls into three categories: the informed, the uninformed and the misinformed.

The informed have tested and mitigated where warranted.  The uninformed don’t know anything about radon

The misinformed believe that radon exists and is a problem only in certain locations, all far removed from them.

Radon is colorless, odorless and tasteless, and it creeps into our homes, offices and schools through cracks and other openings in the foundation of the building.  Once inside it decays into alpha particles that damage the DNA of lung tissue, a major cause of lung cancer.

Once identified as a problem, radon mitigation can be implemented.  Some states like Colorado already require radon-resistant design as part of new home construction.

Testing for radon is easy and homeowners can do it themselves. has a link to one reliable source of radon test kits.  These are the same kits that are used by Radon Professionals for real estate transactions.

Some people are afraid to test for radon because they think that mitigation will be costly, yet the cost is significantly less than what is added to a new vehicle for other safety features like airbags, seatbelts and crushable auto body parts.  When a house is sold, the radon system remains, a bonus to the buyer.

Radon testing becomes more costly if it requires a licensed Radon Professional.  Outside of real estate transactions it can be performed by anyone, following the simple instructions.

The Radon Lady (who is a licensed professional) recommends that everyone test their home themselves with both short term and long term testing.  Short term testing is for 48 hours and give a “snapshot” of the radon buildup over the two days.  Long term testing is 90+ days (6 months is recommended) and shows what the radon levels are like during “normal living conditions.”  “I suggest an initial short term test for approximately $16.  Depending on the radon levels mitigation might be warranted and that’s good to know.  Even if the radon levels are low, however, long term testing should always be implemented.  It costs only $25 and is really the decisive factor of how the home, office or classroom is affected . 

The Radon Lady welcomes your questions about radon at


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