The Bureau opened this classification in 1946 to investigate applicants and employees under the Atomic Energy Act of 1946 and its amendments. Under this act, the FBI had primary responsibility for investigating not only Atomic Energy Commission (AEC) personnel and applicants but also the employees of contractors and licensees who had access to restricted data (information on the manufacture and utilization of atomic weapons, the production of fissionable material, and its use in the production of power, except for information the AEC decides may be published without harm to the common defense and security). The FBI ascertains the subject's true allegiance to the United States or sympathies with any foreign government or idealogy. According to Bureau Bulletin 45, Series 1947, the Bureau could halt an investigation if it found any of the following: (1) proved past of present membership in the Communist Party or other organization declared subversive by the Attorney-General; (2) recent "continuous criminal activity" or conviction for a serious felony in the past 10 years; (3) chronic alcoholism in the past five years; (4) traits indicating mental instability including perversion; (5) Communist Party membership by a close blood relative; (6) recent proved breach of trust or of major security information or other facts overwhelmingly demonstrating that a person would become a security risk. In 1947, the FBI agreed to investigate the staff of the Congressional Joint Committee on Atomic Energy and to investigate whole companies and all their top officers at the AEC's request. This created an enormous volume of applicant/employee cases. As a result, the Bureau decided to investigate only from January 1, 1937, for all but top scientists and certain top officials and to refer only "synopsized reports" to Headquarters, leaving investigative notes in Field Office 1-A envelopes. The Field followed the latter practice from November 1947 to September 1948 when more detailed reports were again forwarded. Despite these changes, the case load became so great that in 1951 the Bureau began to lobby for changes in the law. In October 1952, Public Law 29 transferred many cases to the Civil Service Commission (CSC) and left the FBI with cases of persons in positions of importance or sensitivieity or where the CSC developed evidence of disloyalty.
