Workplace and Schools
Although it was not known at the time, the evidence implicating radon with the risk of lung cancer dates back over 500 years. In the late 1400s it was noted that workers in the area of the Erz Mountains in Eastern Europe, on the boundary between Germany and the Czech Republic, who were engaged in mining for minerals containing precious metals including uranium, commonly succumbed to lung rotting disease. Indeed the disease was so lethal that some local women were repeatedly widowed and were reported to have had up to seven husbands in their own lifetime. It since became clear that the disease in question was lung cancer and that its cause in the miners was the very high level of radon in the underground mines.
Beginning in the 1920s it became clear that uranium miners in several continents were at increased risk of lung cancer from the levels of radon they inhaled underground. In some cases half the number of such miners died of lung cancer. It was also realised that the important radiation dose to the lung was not predominantly from radon-222 itself, rather from two of its alpha-radioactive short-lived decay products, polonium-218 and polonium-214.
It was not until the 1980s that elevated levels of radon were found in domestic properties, but from that time it was recognised that while smoking remained a significant cause of lung cancer in the general population, radon in the home could be responsible for an increased risk of lung cancer.
In 2005 A major Europe-wide study of radon in the home and lung cancer funded by Cancer Research UK and the European Commission was published in the British Medical Journal, ref. [1]. The study authors found a clear relationship between radon exposure in the home and the risk of lung cancer, with a 16% increase in risk per 100 Bq cubic metre increase in radon exposure. The authors estimated that radon in the home accounts for about 9% of deaths from lung cancer in Europe. A recent HPA report, ref. [2], estimates that 1,100 cases of lung cancer per year in the UK may be attributed to radon.
In the European study, the lung cancer risk was found to be higher in smokers compared with non-smokers. In the absence of other causes of death, the study estimates the absolute risks of lung cancer by age 75 years at radon concentrations of 0, 100, and 400 Bq per cubic metre would be about 0.4%, 0.5% and 0.7%, respectively for lifelong non-smokers, and about 25 times greater, 10%, 12% and 16% for cigarette smokers. One important finding from the study was the measurement of an excess risk of lung cancer at 150 Bq per cubic metre, which is below the current UK action level of 200 Bq cubic metre. This finding has led to recommendations for new policy advice for the reduction of radon in UK homes.
Scientific references
[1] Darby S, Hill D, Barros-Dios JM, Baysson H, Bochicchio F, Deo H, Falk R, Forastiere F, Hakama M, Heid I, Kreienbrock L, Kreuzer M, Lagarde F, Mäkeläinen I, Muirhead C, Oberaigner W, Pershagen G, Ruano-Ravina A, Ruosteenoja E, Schaffrath Rosario A, Tirmarche M, Tomášek L, Whitley E, Wichmann HE, Doll R, 2005. Radon in homes and risk of lung cancer: collaborative analysis of individual data from 13 European case-control studies. See paper
[2] Radon and Public Health. Report of the Independent Advisory Group on ionising Radiation. Documents of the Health Protection Agency Radiation, Chemical and Environmental Hazards RCE-11, June 2009. Health Protection Agency Chilton, UK. ISBN 978-0-85951-6440-0