while the comment you're replying to didn't make a distinction, i'll make the distinction that that was a nuclear weapons production facility (run by the federal government). further, some of it was constructed during WWII for the manhattan project.
so... not great handling, true. strong evidence about how nuclear power plants will be operated in the future? no.
https://en.wikipedia.org/wiki/Santa_Susana_Field_Laboratory
https://en.wikipedia.org/wiki/Sodium_Reactor_Experiment
Still not fully cleaned up.