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RADIATION CONTROL PROGRAM

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Granite Countertops and Radiation

Recent news stories have raised concerns about the possibility of radiation coming from granite countertops.

Granite, as with other kinds of rocks and soils, contains some naturally occurring radioactive elements commonly referred to as Naturally Occurring Radioactive Material (NORM). NORM is made up of elements such as thorium, uranium, and potassium, which contribute to what scientists call “background” radiation. Background radiation is a combination of terrestrial and cosmic radiation that individuals are continuously exposed to as part of living on planet earth. In Texas, on average, we receive about 300 millirem each year from these sources. A person would receive approximately 20 millirem from a routine chest x-ray.

The amount of radioactivity in most granite is quite small. While it is possible to get a measurable level of direct radiation from some granite, in general it emits less radiation than we are regularly exposed to from background radiation. These levels are so low that they are not harmful to human health.

Radon is a naturally occurring radioactive gas that can be released during the decay of radioactive elements in granite countertops or can seep into homes from underground uranium deposits, and build up to higher than normal levels.(See: What is Radon?) Most areas of Texas are considered to be at a low risk level for high radon levels (See: The Texas Indoor Radon Survey), but it is still a good idea to test, and know for sure.

Texas Department of State Health Services, along with the U.S. EPA and the U.S. Surgeon General, encourages everyone to test their home for radon. (See: Where Do I Get a Radon Test Kit?)

For more information about the possibility of radon gas coming from granite countertops, please see the EPA’s Frequently Asked Questions about this issue. Some additional information about this issue may be found on the Health Physics Society’s Web site.

For information on Radiation Surveys email Ruben Cortez, or phone 512- 834-6770 ext. 2004.

For general information on Radon EMAIL US , or CALL 1-800-293-0753 ext. 2428 or 512-834-6787 ext. 2428

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What is Radon?

Radon is an odorless, colorless, radioactive gas that develops with the natural breakdown of uranium in soil and rock. Radon can migrate through permeable rocks and soils and eventually seep into buildings or be relased into the atmosphere. Radon is measured in units of picocuries per liter (pCi/l) of radon in the air.

figure showing the decay chain for radon

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What are the Health Risks Associated with Radon?

The only known health risk associated with Radon is the potential to develop lung cancer. In addition, smoking combined with radon exposure greatly increases the risk for developing lung cancer.

sketch of house with arrows, depicting radon gas, flowing through

How are You Exposed to Radon?

Radon that seeps into homes may accumulate there and decay into radioactive, chemically reactive particles that attach themselves to dust in the home environment. If inhaled over a long period of time, these radioactive particles may cause damage to the lung tissues and increase the risk of developing lung cancer.

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The Texas Indoor Radon Survey

In 1991, the Texas Department of Health, Bureau of Radiation Control (BRC) commissioned a statewide survey of indoor residential radon to determine the extent of the problem in Texas, and to identify potential "hot spots." When viewed on a statewide basis, the radon measurements from nearly 2,700 randomly selected Texas homes were relatively low -- averaging 1.0 pCi/l of air. The threshold of concern, according to the Environmental Protection Agency (EPA) guidelines is 4.0 pCi/l air.

Picture of Cover of Texas Indoor Radon Survey and link to survey

Click on the picture of the cover
for the complete survey.
2553KB - 26 pgs.

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Is Radon a Problem in Texas?

In Texas, the average of radon in homes is within national norms; however, when examined on a county-by-county basis, several areas of Texas are identified where local geology is suspected of contributing to the potential for elevated levels of indoor radon.

The Panhandle area of Texas, especially those counties clustered in a band through its center, is shown to have moderate potential for indoor radon. This area of the state is the only area to report any sizable number of homes with radon levels above 20 pCi/l of air, but, on the average, these areas fall within the "Moderate Potential" zone.

Texas has no areas of "Highest Potential," according to the United States Environmental Protection Agency standards.

Click on map for larger image

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How Can I Test for Radon?

There are two principle radon testing methods for home use. The most commonly used method is the short-term charcoal canister test that passively absorbs small amounts of radon over 3-7 days. The canister is subsequently analyzed by an EPA-approved lab.

The other method is a long-term (one month - one year) alpha--track test that detects radiation from radon and is then analyzed by an EPA-approved lab.

Where Do I Get a Radon Test Kit?

While supplies last, the Texas Department of State Health Services (DSHS) is offering free short-term radon test kits to encourage more Texans to test their homes for radon. DSHS has contracted with DrHomeAir to take the orders and mail the kits. You can place an order for a free kit by going to the DrHomeAir Web site, and entering your contact information in the "Texas Radon Program" area. Please note that you may request only one free test kit for an address under this program. The address must be a Texas residence.

Test kits might be found at your local hardware store for about $10 - $15, depending on the demand for kits in your particular area. You may also purchase a test kit online from a number of sources, including DrHomeAir and the National Safety Council.

Please note that if radon levels in the home exceed four (4) picocuries per liter of air (pCi/L) the EPA recommends that homeowners should take action. When using a short-term test kit, additional testing is recommended to confirm the high levels.

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Radon in Schools

The Indoor Air Quality Program, with the assistance of a grant from the EPA, is working with selected schools in Texas to conduct radon testing. While radon has not been found to be a major problem in Texas, the EPA recommends all schools in the U.S. be tested. Texas schools interested in obtaining free radon test kits are encouraged to contact the IAQ Program for more information, at 800-572-5548 ext. 2444 or 2428. Radon in Schools Brochure.

Additional information on radon in schools is available from the EPA.