Homeowners should have radon levels tested during winter

By Thomas Wilson

STAR STAFF
twilson@starhq.com

   As old man winter makes his presence known here in east Tennessee, citizens close the doors and windows to keep in the heat; however, other, dangerous elements can also become trapped indoors. Radon is a naturally occurring radioactive gas that state officials with the Tennessee Department of Environment and Conservation (TDEC) believe warrants testing by homeowners to gauge the level of the gas in their homes.
   "Testing is such an important step because radon is so unpredictable," said TDEC's Radon Program Manager, Cheryl Cole. "Elevated levels of radon are predicted to be in 16% of Tennessee homes, but it varies from region to region and from home to home. Your neighbor's home may be fine while yours may have elevated levels."
   Radon gas develops from the decay of naturally occurring uranium found in soils and rocks in the earth. The colorless, odorless gas wafts from earth and rock, well water and even building materials, and typically rises and disperses in the air.
   However, buildings block the upward flow of radon and allow the gas to seep into them. Radon gas can seep into buildings through cracks and openings in the foundation. The gas isn't detectable by mere sight, taste or smell, and in concentrated levels can pose a threat to human health.
   The U.S. Environmental Protection Agency (EPA) and the National Cancer Institute (NCI) have independently placed the number of lung cancer deaths due to radon exposure at about 15,000 each year in the United States.
   According to medical reports compiled for the EPA and TDEC, radon gas, when inhaled, causes mutations in healthy lung cells and causes cancer with prolonged exposure. Smokers are at a higher risk of developing lung cancer due to radon gas exposure since smoking exacerbates the mutation of lung cells.
   TDEC evaluates the Unaka Mountain area of Northeast Tennessee as being underlain by siltstone, sandstone, quartzite and granite, among other rocks. Homes on phosphate-rich residual soil developed on phosphoric carbonate rocks are among those that may be high in radon.
   While health organizations such as the World Health Organization and American Lung Association agree that radon is a carcinogen, scientists are divided on whether low radon levels, such as those found in residences, increase the risk of lung cancer.
   The EPA reports that small studies of radon and lung cancer in residences have shown a relationship between radon and lung cancer. Other studies have not.
   However, the national and international scientific communities are in agreement that all of these residential studies have been too small to provide conclusive information about radon health risks.
   Science and medical professional do not attribute radon to symptoms such as headaches, coughing, and shortness of breath or fever.
   Based on a national residential radon survey completed in 1991, the average indoor radon level is 1.3 picocuries per liter (pCi/L) in the United States. The average outdoor level is about 0.4 pCi/L.
   The U.S. EPA and the U.S. Geological Survey have evaluated the radon potential in the U.S. and have developed a nationwide map to assist national, state, and local organizations to target their resources and to assist building code officials in deciding whether radon-resistant features are applicable in new construction.
   Carter, Unicoi and Johnson counties are ranked under the Zone 2 category, indicating moderate radon exposure potential. Washington and Sullivan counties rate as Zone 1 ranking with the highest level of radon exposure potential.
   Radon can be a problem in all types of homes, including old homes, new homes, drafty homes, insulated homes, and homes with or without basements. Local geology, construction materials, and how the home was built are among the factors that can affect radon levels in homes.
   In addition, TDEC has partnered with the University of Tennessee Agricultural Extension Service to make radon test kits available in every county of the state. Low-cost kits can be obtained by calling the local county extension agent.
   The best time to test is during consistently cold weather, usually from October to March. Wintertime finds doors and windows shut, so the test results are more representative of in-home exposure.
   Radon testing kits are available at most retail hardware stores, through the American Lung Association, or by calling the Radon Hotline at 1-800-232-1139.