L “" _.. HEADQUARTERS RASK GROUP 7,1, PROVISIONAL APO 187, c/o Postmaster San Francisco, California ~ SUBJECT: TO; § March 1954 Security Letter Al) Personnel 1. Information concerning the detonation of the first in a series of tests is classified CONFIDENTIAL, except for that which has been officially announced in the two (2) AEC releases, dated 9 January 1954 and 1 March 1954 as quoted below: list Release ~- 9 January 1954 "During this month men and material will begin moving to the Pacific Proving Grounds of the Atomic Energy Commission to carry out a further phase of a continuing series of weapons tests of all eategories, These tests are part of the Atomic Energy Commission es “=e researoh program for the improvement of weapons, pursuant to its responsibility under the AEC Act, These tests will be conducted by Joint Task Force Seven (JTF 7), commanded by Major General Percy W. Clarkson, USA, US officials." There will be no observers other than 2nd Release - 1 March 1954 "Louis E, Strauss, Chairman of the United States Atomic Energy Commission announced today that Joint Task Force SEVEN has detonated an atomic device at the Atomic Energy Commission's Pacific Proving Grounds in the Marshall Islands. This detonation was the first in a series of tests,” 2. The fact that an official release was mde regarding the "First detonation in a series of tests," autamtically downgrades that portion of informationto unclassified, HOWEVER, 4+ is desired that no reference be made to this first detonation in letters home, 3, Let the folks back home gain their information through the newspapers, radio and TV, regarding our work here in the Pacific Proving Grounds. . By doing this, there is no possibility of you becoming in- volved in a security leak through misinterpretation of what is classified and what is not classified, BY ORDER OF THE COMMANDER; sme OT oe oe Ahble lel A WLR, A _ Lt Colonel, USAF Personnel Security Officer THE BIGGEST GAP IN SECURITY IS AN OPEN MOUTH SOY Bir ;

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