Last year a tiny radioactive capsule the size of a fingernail went missing in Australia, when a "safe" storage container the size of a small car failed and allowed it to fall out.

The search to find the capsule cost four million dollars and there were global news stories warning people to avoid the highway the (very, very long) highway the truck had driven down.

In other countries (e.g. Soviet ones) where precautions like that haven't been taken, those capsules have been found after dozens of people caught cancer due to regular exposure to a capsule that just happened to end up near them. Presumably there are more that haven't been found, and those countries just accept a higher rate of cancer than the rest of the world.

Avoiding those scenarios is what costs so much.