FAQs
Radon, Radiation and Granite
Q. What is radon?
A. Radon (Rn) is an inert gas that results from the decay of uranium in natural stone. Its discovery is credited to a German physicist named Fredrich Ernst Dorn in 1900. The gas is tasteless, colorless and odorless, so radon is undetectable to humans. In the U.S., radon is commonly measured in picocuries per liter (pCi/L). In addition to emitting potentially carcinogenic gases, radon is radioactive. High levels of radon are found in granite-type igneous rocks where uranium is typically present.
Q. What is radiation?
A. Radiation is produced when radioactive materials decay and give off or emit energy in waves or particles. This energy is powerful enough to break chemical bonds and/or strip away electrons from atoms. There are three primary types of radiation: alpha, beta and gamma. Alpha and beta are moving subatomic particles. A sheet of paper can stop an alpha particle, whereas beta particles can actually penetrate human skin. Gamma rays are, by far, the most powerful and can penetrate a brick wall or sheet of lead.
According to the EPA, "health physicists generally agree on limiting a person's exposure beyond background radiation to about 100 millirems (mrem - dose rate, or amount of radiation absorbed by the tissue in the human body) per year from all sources." Additionally, the "EPA and other regulatory agencies generally limit exposures from specific source to the public to levels well under 100 mrem."
Q. What are the effects of radon exposure?
A. Radon has been associated with lung cancer and other respiratory illnesses. In 2005, the U.S. Surgeon General issued a national health advisory about the relationship between radon and cancer that cited more than 20,000 people die of radon-related lung cancer every year in the United States. The National Cancer Institute reports that radon-induced lung cancer costs the U.S. upwards of $2 billion a year in indirect and direct healthcare costs. For a number of years, the EPA has provided abundant information to consumers about radon. The EPA has also established 4 pCi/L as the "action" guideline level for radon exposure. However, there are potential health risks associated with exposure to radon levels as low as 0.2 pCi/L.
Q. How does radon cause lung cancer?
A. When inhaled directly, radon gas bombards lung tissue cells with radioactive energy but also deposits solid particulates that remain in lung membranes and continue to decay. With sustained exposure, this "attack" on human lung tissue can cause cancer. Susceptibility to serious disease is dependent on a number of factors, including breathing rates, site of impact and overall health, among others.
Q. What are the effects of radiation exposure?
A. According to the EPA, "in general, the amount and duration of radiation exposure affects the severity or type of health effect." There are two broad categories of health effects - those associated with "long-term, low-level (chronic) exposure to radiation" and those appearing in "cases of exposure to high levels of radiation," (also known as 'acute' exposure).
The primary health effects associated with long-term, low-level exposure to radiation are cancer and DNA mutations. The health effects from acute exposure include "burns and radiation sickness (also called 'radiation poisoning'). The symptoms of radiation sickness include: nausea, weakness, hair loss, skin burns or diminished organ function."
Q. If I don't live in a geographical location with a history of radon in the area, am I safe?
A. Not necessarily. Radon comes from the earth itself and is found in groundwater in many areas of the country where natural rock formations have been associated with radon emissions for years. Not only that, but new evidence supports the possibility that utilizing natural stone products indoors - especially in homes or workspaces that with limited air circulation - may emit harmful levels of radon over time. All of that - combined with the fact the volume of granite imported to the U.S. has increased nearly 200 percent in only six years - should concern builders, retailers and consumers.
Q. What commonly used building materials emit radon?
A. Again, we're not sure. That's the problem. Radon has been measured in the laboratory from many popular granite countertop colors and in field tests of concrete, ceramic tile and other materials, so the only way to be sure that your own home is safe is to test regularly for radon and radiation or choose alternative products if building a new home or office.
Q. How can I find out more about radon?
A. Abundant information is available about radon and radiation on the Internet and from our website, http://www.buildclean.org . The EPA, in particular, provides extensive guidelines for radon and radiation exposure; however, it is important to note, that the relationship between indoor building materials and radon is only beginning to be studied. That's why it's important to support BuildCleanTM.
Radon and Radiation Testing
Q. What should importers, fabricators or resellers of indoor granite products be doing?
A. We believe they should ensure that all natural stone products are tested for radon and radiation emanation before putting them on the market. The tests exist today and are not expensive. It's the responsible thing to do.
Q. How can I tell if I have radon in my home?
A. The only sure way to know is to conduct a relatively inexpensive in-home test over a period of at least two weeks in areas of the house where natural stone materials have been used in flooring, bathrooms, countertops, for example. If the test indicates levels of radon at 2-4 ( pCi/L) or higher, we recommend hiring a professional technician to conduct additional tests.
Q. Is there any connection between energy efficiency and radon exposure?
A. Radon is potentially injurious to health in spaces with poor or limited air circulation. So, if your home is closed up for much of the day or week, or if it is always heated or cooled without effective fresh-air ventilation, that area could retain higher levels of radon in the air. If you or a family member is exposed to radon emissions in such spaces over time, your risk is certainly higher. Newer homes, in particular, which have been "sealed" tightly to decrease loss of heated or cooled air, without adding fresh-air ventilation, may increase exposure to radon. The problem is no one has done a comprehensive study of indoor radon emanations under a variety of conditions.
Q. What options exist for reducing radon and/or radiation concentrations from indoor building materials, such as countertops and floors, without a major home renovation?
A. In terms of reducing radon levels in a home caused by indoor building materials, either removing the source of exposure or, in some cases, increasing the circulation of fresh air throughout the house, may eliminate the problem. More research - both in the laboratory and in realistic home situations - is needed.
In order to reduce radiation levels related to indoor building materials, the source of the emanation would need to be removed from the home.
Q. How can I get my home tested for radon and radiation?
A. Many radon home test kits are available today, ranging from very inexpensive "one-shot" tests to permanent devices that constantly measure radon emissions. There are also certified radon inspectors that can be contracted to conduct the tests and analyze the results.
Radiation can be tested using commercially available radioactivity meters.
Today, the Internet is a great resource to find more information and resources in your area, and BuildCleanTM will be expanding the Resources page on our website, so please check back regularly.
Q. How often should my home be tested for radon and/or radiation?
A. Since radon and radiation emanate over time as uranium and other elements decay in rock, the only sure way to know if a home is contaminated with dangerous levels of radon and radiation is to test several rooms over time and under a variety of conditions. It would also be ideal to have specific granite countertop samples tested in a laboratory.


Q. How should I approach my fabricators/reseller/installer about testing the natural stone products I am considering for my home?
A. We believe importers, fabricators and resellers should voluntarily test all natural stone products for radiation and radon emissions before selling them to consumers; however, until there is a volume of research available to foster a better understanding of which stone products carry the greatest risk, it is unlikely that we will see an across-the-board movement toward testing prior to re-selling - except on the part of socially responsible companies.
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