[foxglacier]

In addition, this society has to fail to identify what the resulting health problems were caused by. If only the people who ate the excavated material or live in its vicinity get sick, that should eventually be obvious before they spread it to the whole human population through their weird global religion.

[bumby]

The tough part about radiation itself isn't painful so causality can be hard to ascertain.

[foxglacier]

Yea it might take many years but if it's a big enough problem, it would surely be obvious that only the cask-contents-munchers are having deformed babies or whatever.