 The name "actinon" for 219Rn is rarely encountered today, probably due to the short half-life of that isotope.The danger of high exposure to radon in mines, where exposures can reach 1,000,000 Bq/m3, has long been known.In 1530, Paracelsus described a wasting disease of miners, the "mala metallorum", and Georg Agricola recommended ventilation in mines to avoid this mountain sickness ("Bergsucht").