Rocky Flats is where the countries nukes were made. Where the plutonium was processed into triggers.
It was raided by the FBI for violating environmental laws and the government(at the time) covered it up.
Then closed down a few years later for a couple reasons- one was the danger(Denver, a growing city, was 20 miles away) and one was they had enough nukes and were subject to nuke treaties and had to downsize the fleet(which gave them more plutonium from the old bombs), and placed on the superfund site, and fast tracked to quick cleanup.
I understand...100 kilos of plutonium went missing.
https://en.wikipedia.org/wiki/Rocky_Flats_Plant
Now...The land is basically in the middle of the suburbs and been turned into a wildlife refuge(still too "hot" for people to visit), with housing right up against the fence.