Radon In Your Basement
We once saw a science fiction movie in which a monster from outer space is first detected because it sets Geiger counters clicking furiously. We were reminded of that movie by the story of how radon in homes first came to wide public attention. A nuclear power plant was built in a town in Pennsylvania, and like all such plants was equipped with radiation detectors, both to protect the health of employees and to prevent anyone from removing nuclear fuel from the plant. A newly employed engineer at the plant registered a high radioactivity when he walked by the detectors. This was not only alarming but surprising: the plant was not yet operating, and there should not have been any radioactive material around. It was quickly established that the source of the radiation was not the plant but the engineer’s house in a nearby suburban community, which had levels of radioactivity almost a thousand times greater than federal standards permit in mines. The radioactivity came from radon gas seeping into the house from the ground. Cigarette smoking is responsible for about 90% of lung cancers, but 10% of the victims of this disease had never smoked. It was already known that miners exposed to radon gas in uranium mines suffered a high rate of lung cancer, and the question immediately arose: could radon gas in homes be another cause of lung cancer? Radon in homes is not a consequence of the atomic bomb or the building of nuclear power plants; it is one of the major sources of the natural background radiation we are all exposed to. It is present even in outdoor air, and at higher concentrations in homes, castles, peasants’ hovels, and caves as long as people have lived in them. It is a product of the decay of the element uranium. Uranium is present to some extent in all minerals, so we expect to find more radon in houses built of stone or mineral products like stone, concrete, and gypsum than in houses built of wood, and we expect to find more of it in basements than in attics.