Homebuyers often request radon tests, sometimes to be paid by the seller. The test may be required as part of the purchase contract to protect the homebuyer. Sometimes a conflict of interest can arise, where the team that would do the remediation is also the team that does the testing. Remediation -- namely ventilation -- can cost more than $1,000, which leads some sellers to question the validity of those performing the tests and even the selection of the Evironmental Protection Agency-recommended radon limits and the link of radon to lung cancer.
Radiation is a natural part of the environment. All people receive exposure from naturally occurring radioactivity in soil, water, air and food. To limit its effect, it is helpful to know that the largest source of natural radiation exposure is from radon, whose exposure we fortunately can control.
Radon is a radioactive element formed by the disintegration of radium. It is the heaviest of the noble gases, and therefore builds up in the lowest levels of the house. It occurs naturally, especially in areas over granite. If vented to the outdoors, where it can be scattered by the wind, it is relatively harmless. However, if a house is built over a source, then the lower parts of the house can fill with the gas, and radioactive particles can accumulate in the lungs until they disintegrate.
Frequency of Problem
Skeptics believe that radon is so infrequently above EPA limits that testing is not worthwhile. Actually, the National Safety Council reports that nearly one out of every 15 homes has a radon level above the EPA-recommended limit of 4 pCi/L. The U.S. average air level of radon in single-family homes is 1.3 pCi/L.
One picoCurie (pCi) is one trillionth of a Curie, or 0.037 radioactive disintegrations per second. So 4 pCi/L is 12,800 disintegrations in one liter (L) of air per day.
Skeptics further have suggested that only very few parts of the country have a significant number of residences with radon problems. This is not the case. A radon map provided by the EPA (see Resources) gives average radon levels, not variances. Homes with elevated levels have been found in all three zones.
The EPA-recommended Limit
Some skeptics charge that the EPA-recommended limit for radon levels is reckless extrapolation from extreme cases of radon exposure. The EPA states that any radon exposure carries some risk; no level of radon exposure is always safe. Therefore a limit needs to be set somewhere. The limit selected by the EPA is not arbitrary but informed by epidemiological studies like the Iowa Radon Lung Cancer Study(see Resources). Major health organizations--including the Centers for Disease Control, the American Lung Association and the American Medical Association--agree with estimates that radon causes thousands of preventable lung cancer deaths every year, especially among smokers.
Conflict of Interest
You can take steps to prevent conflict of interest in regard to radon testing when selling a house. For instance, you can add line to the contract to stipulate that a team of the seller's choosing would perform the remediation. (The inspector should be notified of this in advance, if possible.) Also, as a seller you can double-check the inspector's radon test with a home radon test kit for around $15.