Radon in Your Home

— Written By Susan Condlin and last updated by Kay Morton

Radon is once again in the headlines and just this past week, I heard several radio commercials related to radon and have had a couple of calls. Compounding the need for today’s article is also the concerns related to granite countertops and radon exposure.

Radon is a naturally occurring radioactive gas, produced by the normal decay of uranium in rock and soil. As uranium decays, it produces radium, which in turn, releases radon gas. You cannot see, smell or taste radon. Once released, this gas rises to the surface of the soil and escapes into the atmosphere or into a building. Radon can seep through dirt floors, cracks in concrete walls and floors, floor drains, sump pumps, joints and hollow block walls to enter your home.

When inhaled, radon particles tend to lodge in the lungs and emit radiation, which damages surrounding lung tissue. The health risk of excessive exposure to radon gas is an increased risk of lung cancer. Radon gas exposure has been estimated to contribute to 20,000 lung cancer deaths each year. Smokers are at higher risk of developing radon-induced lung cancer.

Radon can be found in all fifty states. While radon problems may be more common in the upper piedmont and mountain counties of North Carolina, any home may have an elevated radon level. New and old homes, well-sealed and drafty homes, and homes with or without basements can have a problem. The only way to determine the level is to conduct a radon test. The amount of radon in the air is measured in “picoCuries per liter of air,” or “pCi/L.” Sometimes test results are expressed in Working Levels (WL) rather than picoCuries per liter (pCi/L). The EPA and the Centers for Disease Control and Prevention recommend that all homes be tested for radon and homes with radon levels at or above 4 pCi/L be repaired to reduce the amount of radon entering the indoor air. Indoor radon levels can vary from home to home so don’t rely on radon test results taken in the neighborhood, even ones next door, to estimate the radon level in your home. In 1990, seventy-three homes in Lee County participated in a radon test conducted by Cooperative Extension. Our county did not have one home testing over 4pCi/l. The EPA Radon Zone Map for NC shows Lee County in zone 3 with the average predicted indoor radon levels of less than 2 pCI/l.

There are many kinds of low-cost “do-it-yourself” radon test kits you can get at local hardware and home improvement stores. The cost runs around $15 to $25 and includes lab and mailing fees. The NC Radon program was distributing free kits, but that supply has been exhausted. Their website does have a source for purchasing radon meters. If you should have a reading greater than 4pCi/l, additional testing is recommended with possible mitigation. For this you will want to consultant a certified radon professional. A list of these testers can be found on the NC Radon website at http://www.ncradon.org/

There has been an increased interest in radon related to granite counter tops. This concern is nothing new; radon in granite countertops has surfaced several times over the past ten years. While it is possible that granite counter tops can release radon, the NC Radon Program reports the instances of this happening are very infrequent. The program suggest homeowners focus on testing the radon in the air rather than trying to test the granite counter tops as the health risk comes from breathing the radon and there is not an easy and inexpensive way to test granite counter tops. Testing for radon in the air would be the first step, then if it appears that radon is higher in the kitchen than the basement (the more typical area for radon entry), you could begin focusing on the granite counter tops as the source of the problem. Radon coming from granite countertops quickly diffuses into the air. In July of 2008 EPA confirmed that granite countertops are not a realistic source of radon gas and the general pubic should not be concerned about having granite countertops in the home. If you would like more information on this topic, give me a call at 775-5624.

Susan Condlin is County Extension Director for North Carolina Cooperative Extension in Lee County.