This is for the most part not a realistic practical issue. Either the civilizations in the future are continuations of our current civilization and have records

This is for the most part not a realistic practical issue. Either the civilizations in the future are continuations of our current civilization and have records or they're advanced enough to have the ability to detect radiation thus making the issue moot or they've regressed enough to lose that knowledge and people stumbling into a radioactive waste storage facility is the least of our concerns.