HEADQUARTERS JOINT TASK FORCE SEVEN Washington 25, D.C. _193/729.3 li Cecenber 1953 SUBST: Safety Measures During Operational Pnese of CASTLE TO: Commander in Chief, Pacific c/o Fle .. San F pst Office , California | ~ l. References: a. Gurr 132 Secret letter, subject: "Safety Measures Cure ing Operational Phase of IVY", dated i July 1952. "b, CUTF SEVEN Secret Letter, subjSct: "Schedule of Messages Concerning Detonations During CASTLE", dated 3 Decanber 1953. 2 It is antleipated that theshot hazards introduced into the Pacific arca during Operation CASTES will, with one exception, closely perslie] tucee. gncountared eon the IVY-HIXS shot. The mception is expested to. occur, due to reduced yield, on the ECHO shot at Eniwetok Atel. Accordingly, the general inforsation prosented in above ref- erence on IVY safety mcasurcs, and restated below with pertinent nodifications, is conaidurod applicable to Operation CASTLE. . Me. thth respoet to the probability of fall-out hazards, it is concluded that the axistanse of euch at UJILANG 1s a remte possi- ae pian eer at, othur islands in the vicinity of shot sites ergsidaped. vary yenots. Tho inpect of fbli-dut on populated islands wit poeofSoe ander factors in the task force commandor's decision will be considered in its relation ta forvucast winds and conditions. Intho event that cogent and compel- tinepaost-ghot reseons arise requiring temporary evactstion ofnctives, task fores security ships will, be aide available to CINCP«C for this - parposea. Personnel with Trust Territory administration and interpre= eee experienca would bo required froma your command to supervise this ort. . , be Although various uncertatnticexist in prodetormining the trajectory |of an atomic cloud with resultant radionctiva fall-out, all possiblensasures to cinimizo health hazards will be taken dy this commind. CJTF SEVEN will uso weather 1s 4 osjor safety coasure, dcton= ating the encts at s tina whon wind conditions prosant ainima hozards Inel & to TaB "C" e-413