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 and tar and caulk used to plug seams. On 28 and 29 July, the DSM conducted a small-scale laboratory study on painted wood, steel, and canvas using soap powder, lye, and naphtha; acetic, hydrochloric, and sulfuric acids; and flour, cornstarch, activated charcoal, and sandblasting. Removal of the outer layer of paint or removal of the rust proved to be an effective, if laborious, approach. Apparently only acetic acid worked on canvas (Reference C.9.185; Reference A.2, p. 109).

From 28 through 30 July, large-scale experiments were conducted on the target submarine USS Tuna (SS-203). The submarine was sprayed first with diesel oil, which proved ineffective as a detergent. However, a 66 percent reduction in radiation level was observed after much of the submarine's paint was removed by applications of a lye and boiler compound solution followed by a saltwater rinse (Reference C.9.185, p. 8). This encouraged the DSM to issue general instructions on 31 July for preliminary decontamination of target vessels, followed on 4 August with more detailed instructions. The procedure called for the fireboats to spray each contaminated target ship with saltwater and with the lye and boiler compound solution if needed. Once the radiation level was reduced to the point where personnel could remain for at least 2 hours, the ship's crew was to work in relays thoroughly scrubbing the ship. Figures 36 and 37 show ships' forces scrubbing an unidentified submarine and a ship. Clearly, the DSM expected that this procedure would lead to radiation levels low enough to allow continuous habitation of the ships so that they could return to home ports under their own power (Reference C.9.187, pp. 4, 7, and 10).

Figure 36. Work crews scrubbing down an unidentified target submarine, CROSSROADS.

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