> but natural uranium in rocks is full of fission products.
They're dangerous too. Natural Uranium decay creates radon gas, which seeps up through the ground an accumulates inside buildings. That radon then decays, and the products of that cause lung cancers that kill more than 20 thousand people in America every year, and contribute to 2% of cancer deaths in Europe.
I grew up in one of those areas; in public school they taught us about the importance of radon testing and making sure your house, basement particularly, is well ventilated.
An frightening anecdote from wikipedia:
> The danger of radon exposure in dwellings received more widespread public awareness after 1984, as a result of a case of Stanley Watras, an employee at the Limerick nuclear power plant in Pennsylvania. Mr. Watras set off the radiation alarms (see Geiger counter) on his way into work for two weeks straight while authorities searched for the source of the contamination. They were shocked to find that the source was astonishingly high levels of radon in his basement and it was not related to the nuclear plant. The risks associated with living in his house were estimated to be equivalent to smoking 135 packs of cigarettes every day.
