President Truman signs legislation transferring atomic energy oversight from military to civilian authority, establishing classified information protocols effective January 1, 1947.
Background
Legislative Action
President Harry Truman signed the Atomic Energy Act on August 1, 1946, fundamentally restructuring governance of nuclear materials and information in the United States.
Effective Date and Scope
The legislation took effect on January 1, 1947, transferring control of atomic energy from military to civilian administration. The act established that information on atomic energy is classified at its origin, regardless of whether created by government agencies.
Classification Framework
The law introduced a multi-tiered classification system for atomic information. "Restricted Data" functions as a content designation rather than a classification level itself. Documents can be classified as Confidential, Secret, or Top Secret while simultaneously containing Restricted Data. Additional designations include Critical Nuclear Weapon Design Information, creating combinations such as Secret//Restricted Data or Secret//Restricted Data-Critical Nuclear Weapon Design Information.