How do government agencies determine radiation levels are safe?

Mr Edano of Japan indicated radiation levels in food were not harmful to human health.



I'm tired of hearing about opinions of politicians or even corporate scientists. The scientist I trust said there was no safe level of radiation, even background radiation. What scientific study determined that a given level of radiation is safe? If I eat, drink, or breath a single radioactive particle, I know that a cancer tumor will be instantiated. 'Safe level' my A-R-S-E?#!How do government agencies determine radiation levels are safe?
There is an Internationally agreed measure. Whether they are deliberately underestimating, as they did at Chernobyl and Three Mile Island, is another matter. By the way, there is no such word as 'instantiated'.How do government agencies determine radiation levels are safe?
Well, background radiation is unavoidable. Unless you want to sit in a lead box for your whole life, you're going to receive some ionizing radiation, which comes from the sun's solar wind and from minerals in the ground. By "safe" level they mean that the extra level of radiation is OK to be in for a short time.How do government agencies determine radiation levels are safe?
As you point out we receive some radiation from natural sources and the criteria they use is that it is less than a significant fraction of the background.
They send in some welfare recipients. If they get cancer in Five years, it was not safe. If they do not get cancer until ten years, it was safe.