Radon: further evidence of risk at relatively low exposure

Radon in the human body

Radon increases the risk of lung cancer. This was scientifically proven by evaluating health data from uranium miners, some of whom were exposed to extremely high radon concentrations. But even at comparatively low radon concentrations (as can still occur in some workplaces and sometimes in homes), the risk of lung cancer increases in a linear manner with the level of total exposure..

This is a partial result of the PUMA (Pooled Uranium Miners Analysis) study in which data from seven uranium miner studies from the US, France, Canada, the Czech Republic, and Germany were jointly analysed with the participation of scientists from the Federal Office for Radiation Protection (BfS). The evaluation, which was published in "Environmental Health Perspectives", confirms the results of earlier studies with a much smaller data base.

Lung cancer risk depends not only on the level of exposure

In addition to the total level of radon exposure, two other factors influence the risk of lung cancer.

• Regardless of when the miners were exposed to radon, the risk of developing lung cancer decreases with increasing age.
• Also if exposure occurred more than 15 years ago, the risk of lung cancer tends to decrease.

The evaluation of the PUMA study confirms that the interrelationships between radon and lung cancer observed at high radon exposures apply to comparatively low exposures as well.

Findings relevant for current radiation protection

Drilling miners working underground while standing in shallow water

The evaluation included data from almost 58,000 male miners who started working in uranium mines in 1960 or later. Whilst hardly any radiation protection measures were taken in the early years of uranium mining, by the 1960s, they were so well established that miners were exposed to only comparatively low radon concentrations. The findings from the study are thus also relevant for current radiation protection at the workplace as well as for the protection of the general population from radon.

The PUMA study

The PUMA study summarises data from nearly 125,000 miners worldwide who worked in uranium mining between 1942 and 1996. As the largest single study, the Wismut uranium miners cohort study contributes almost half of the total data volume. The Wismut study is a cohort study conducted by the BfS on 64,000 former employees of the Wismut uranium ore mine in Thuringia and Saxony.

The PUMA study will also provide further insights into whether radon can cause diseases other than lung cancer.