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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 released into the atmosphere. Radon is measured in units of picocuries per liter (pCi/l) of radon in the air.

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.

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.



Radon Decay Chain Radiation Source
healthy family

Radon Standards of Practice

Standards and protocols for conducting radon measurement and mitigation activities have been available since the early 1990s, and were developed in several ways: first, by EPA with radon industry input; second, under the ASTM standards development process; and third, by the ANSI-recognized American Association of Radon Scientists and Technologists (AARST) Consortium on National Radon Standards.

One or more of these standards have been recognized or adopted in several ways:  first, by various states with radon licensing or certification requirements; second, by EPA; and third, by national radon proficiency programs, of which there are two, the AARST-National Radon Proficiency Program (AARST-NRPP), and the National Radon Safety Board (NRSB).
Radon measurement and mitigation professionals should identify which standard and/or protocol they are following or comply with, usually determined by the state certification program or national certification program they participate in.

More information is available on the EPA radon web site: use the link:
There you will find two lists of radon standards – Current Standards and Older Standards

The AARST –National Radon Proficiency Program lists its recognized standards here:
The National Radon Safety Board does not have a listing of recognized standards.

Radon Logo

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?)

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.

 The Texas Indoor Radon Survey

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.

Past Published EPA Data


Unpublished EPA Data