Scientists say that exposure to low levels of radon gas, which generally percolates out of the ground into basements, seems to reduce the risk of developing lung cancer by about 60 per cent.
This inference is based on the observations made during a study by experts at Worcester Polytechnic Institute, Fallon Clinic, and Fallon Community Health Plan.
The researchers say that the levels of exposure that appeared to reduce the risk of lung cancer in the study, involving about 600 Massachusetts homes, were nearly the same as typically found in 90 per cent of American homes.
The finding differs significantly from the results of previous case-control studies of the effects of low-level radon exposure, which have detected a slightly elevated lung cancer risk or no risk at all.
It is significant due to the fact that home exposure to radon has been thought to be the second leading cause of lung cancer, after cigarette smoking.
A paper describing their study, published in the journal Health Physics, says that it was for the first time during the instant study that a team of researchers observed a statistically significant hormetic effect of low-level radon exposure.
Lead researcher Donald F. Nelson, Emeritus professor of Physics at WPI, initiated and managed the study amid growing concern over the suggested link between residential radon exposure and lung cancer.
He says that the main purpose of the study was to determine what level of radon exposure actually correlated with significant lung cancer risk, and to establish a safety zone for home radon levels.