Last month's article in the British Medical Journal on the dangers posed by radon gas in buildings jogged my awareness of this important hazard (Gray, Read et al. 2009).  Quoting Wikipedia on radon "Radon is the invisible, radioactive mono-atomic gas that results from radioactive decay of some forms of uranium that may be found in rock formations beneath buildings or in certain building materials themselves. There are relatively simple tests for radon gas, but these tests are not commonly done, even in areas of known systematic hazards." and "According to the United States Environmental Protection Agency, radon is reportedly the second most frequent cause of lung cancer, after cigarette smoking; and radon-induced lung cancer the 6th leading cause of cancer death overall." and "Some ... areas, including Cornwall and Aberdeenshire in the United Kingdom have high enough natural radiation levels that nuclear licensed sites cannot be built there - the sites would already exceed legal radiation limits before they opened, and the natural topsoil and rock would all have to be disposed of as low-level nuclear waste."

Back in 2005, Geoff Watts wrote a freely viewable BMJ editorial entitled "Radon Blues" that provides good background orientation about this problem (Watts 2005).  In the US it's estimated that nearly 1 out of every 15 homes has elevated radon levels.  You can check whether your home or place of work/education is likely to have a radon problem by viewing relevant maps.  More detailed US local information can be found by visiting the Environmental Protection Agency.  In England and Wales download the 36 page PDF maps document produced by the Health Protection Agency.  Detailed information is harder to come by for Scotland and Northern Ireland, although visiting this HPA document is useful.  For more on radon testing for homes or work places in the UK, see the relevant section of the HPA site and also the BRE site.  Geoff Watts' BMJ editorial "Radon Blues" concludes "One form of negligence that's harder to overcome is a disinclination to do anything at all. A brief review of domestic radon published three years ago by the Parliamentary Office of Science and Technology made gloomy reading.  It reported estimates by NRPB that the gas significantly affects around 100000 properties in Britain.  Of householders whose radon was above the recommended action level (200 Bq/m3), only about 10% were actually tackling the problem.  NRPB says it has no reason to believe that the figure has subsequently improved.  Why the poor showing?  The Parliamentary Office of Science and Technology identified four factors: a reluctance to do anything if the radon concentration is only slightly above the action level; a tolerance of "natural" radiation as opposed to its equivalent from the nuclear industry; inadequate access to reliable advice; and, of course, simple inertia.  Reflecting on his life's work, a distinguished radiation biologist once regretted that radioactivity was invisible.  He'd always wished, he said, that he could paint it blue.  Maybe our enthusiasm for home protection would get a boost if the gas percolating up through the floorboards had some equally eye catching colour."

Gray, A., S. Read, et al. (2009). "Lung cancer deaths from indoor radon and the cost effectiveness and potential of policies to reduce them." BMJ 338(jan06_1): a3110-.  [Abstract/Free Full Text]

Watts, G. (2005). "Radon blues." Bmj 330(7485): 226-7.  [Extract/Free Full Text]