The great cover-up of the Rocketdyne Santa Susana Field Laboratory nuclear accident in 1959 – the worst on U.S. soil because there was no containment building.  Information only came out 20 years later when some of Dan Hirsch’s nuclear policy students at UC Santa Cruz did research and discovered the long-hidden documents that proved it.  52 years after meltdown, it’s still being cleaned up.  Link here: