September 29, 1957......Mayak Nuclear Power Plant Explosion

September 29, 1957 - 20 MCi (740 petabecquerels) of radioactive material is released in an explosion at the Soviet Mayak nuclear plant at Chelyabinsk.

From http://en.wikipedia.org/wiki/Mayak#The_1957_accident

According to Gyorgy (1979: 128), who invoked the Freedom of Information Act to open up the relevant Central Intelligence Agency (CIA) files, the CIA knew of the 1957 Mayak accident all along, but kept it secret to prevent adverse consequences for the fledgling USA nuclear industry. "Ralph Nader surmised that the information had not been released because of the reluctance of the CIA to highlight a nuclear accident in the USSR, that could cause concern among people living near nuclear facilities in the USA" (Pollock 1978: 9). Only in 1992, shortly after the fall of the USSR, did the Russians officially acknowledge the accident.

I will never cease to be amazed how a part of the American government decides it is for our own good to keep the public in the dark, even about something as critical as this. This proves even more topical with the current administration trying to whip up support for building new nuclear power plants to reduce our dependence on oil. I have faith that the American public can handle the full unvarnished truth a lot easier than finding out after the fact we have been fed a line of dangerous ignorant bullshit.