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Usually any alpha emitter, when absorbed and held in proximity to tissue is a carcinogen. An alpha decay typically gives off a gamma around 1/2 MeV, and the alphas from most natural isotopes are 4-5MeV. In WWII, young women painted altimeter dials with radium luminous paint. Radium occupies the same row in the periodic table as calcium. The women's bones were still growing, and the body took up Group IIA metals thinking they were calcium. This included Radium 226. Many died of bone cancers years later. Photomicrographs of bone showed "Alpha Tracks" made by the particles over the years. Addtionally, one carcinogen suspect in tobacco smoke is Polonium 210, which is found in the superphosphate fertilizers used on the crop. Lung cancers from Radons are caused not by the radon, but by the daughter isotopes that float around in the air, and attract dust particles so the clumps are exactly the right size (4-10 microns) to make it into the lung.

Lung cancers from Radons are caused not by the radon, but by the daughter isotopes that float around in the air, and attract dust particles so the clumps are exactly the right size (4-10 microns) to make it into the lung.

Thanks for making my original point that inhaled radon is associated with lung cancer. 10 micron particles are on the large side for inhilation, aren't they? I've not heard of radon being associated with bladder cancer because inhilation is the normal route of exposure, not ingestion or absoption.

As an RSO (are you also a health physicist?) you'd have good insight as to the possibility or probability of radon-induced bladder cancer. I'm skeptical, but open to the possibility.

In WWII, young women painted altimeter dials with radium luminous paint. Radium occupies the same row in the periodic table as calcium. The women's bones were still growing, and the body took up Group IIA metals thinking they were calcium. This included Radium 226. Many died of bone cancers years later.

I believe they also had the habit of 'tipping off' the brushes between their lips.

My dad was in the business of finishing watch dials. I watched him build a small lead box for the vials of radium compound, which he stored in the company vault and provided with ventilation to the outside. He also had installed exhaust vents right near each dial painting station.