About 20 years ago near the village Lia, Georgia (the country), three men found some funny devices that generated heat while collecting for firewood in the forest. They were too hot to touch and the snow around them had melted. Cool, the men thought, we’ll set up camp here, no need to built a fire for the night.
Turned out those devices were lost radioisotope thermoelectric generators from an unfinished soviet era project. The strontium-90 within poisoned the men. Later examination showed it radiated close to 5 Sieverts per hour which is about the dose that gives a 50-50 shot at survival. One of the men got away lightly, one was hospitalized for a year and the third finally died after 2.5 years.
Moral of the story is the only radiation you can feel directly is heat.
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