RELEASING the biggest wave of classified nuclear secrets ever to pour out of Washington, US energy secretary Hazel O'Leary admitted that between 1945 and 1990, the country had conducted 204 secret underground nuclear tests and 48 in the Pacific Ocean. These exclude the 826 tests the US had earlier admitted to conducting.

O'Leary also promised to release information on the amount of weapons-grade plutonium held by the government and the exposure of humans to plutonium in a series of tests during the Cold War.