You can be killed by anything in a large enough dose.
For a single sitting of eating chocolate, for a human it is something like 4 tonnes.
Anyway, where you live can also be carcenogenic.
I live over the Granite rocks which make up the south western peninsula of England, the most radioactive place in the UK.There are a number of people here every year dying from Radiation poisoning, mainly caused by the huge amount of Uranium sitting under the granite, which turns into Radon gas, which permiates through the rock and into people's houses, causing radiation poisoning. Fun.