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Miners in what is now Austria died relatively young as a result of exposure to it. The Swiss physician Paracelsus identified their cause of death as a "wasting disease," and German scientist Georg Agricola suggested that mines be ventilated to protect miners.
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A study of miners in the Ore Mountains shows that the lung disease killing miners is cancer, and in some mines it kills 75% of the miners. The "gas" is later though to have been radon emanation.
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A gas that radiated from Radium remained radioactive for over a month. This "gas" was discovered to be Radon years later.
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Friedrich Ernst Dorn discovers "radium emanation", later known as Radon-222.
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Dorn publishes a paper that had been inspired by previous work that Ernest Rutherford had done on the radioactive element thorium, verifying that just like thorium, radium emitted a gas.
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Chemists Sir William Ramsay and Robert Whytlaw-Gray were able to isolate radon and study its physical properties such as density and weight. They concluded that radon was the heaviest known gas.
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Inhalation of radon is introduced as treatment for rheumatism and gout.
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The element is formally named radon and identifies with argon and xenon as a noble gas.
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Rajewski suggests that radon is the cause of high lung cancer rates in some German mines, including one known as the ‘death mine’.
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Bale recognises that it is radon decay products, not radon gas, that give high radiation doses to the lungs.
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High radon levels are found in some Swedish homes, but are thought to be a local problem caused by particular building materials.
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High radon levels are found in some UK homes - large scale surveys are started.
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Research shows that the main source of indoor radon is air in the ground, drawn into buildings by underpressure indoors.
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World Health Organisation recommends action to reduce high radon concentrations in homes.
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ICRF study of lung cancer in Cornwall and Devon gives radon risk estimates similar to those from the miner studies.
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EU regulations on targets levels likely to be further revised downwards to 100 Bq/m3 for the home and 300 Bq/m3 for workplaces.
