WaiAn Curry au neq This sums phunomena was notud during Operation [vy on the anders ~8urfaces of the USS Lipan and in the condensers of tha USS Randova. Under our present limits of tolerance, an uifouled ship could _ remain in waters of 10 ar/day indefinitely, but snips with micro organic growths, rust, and adsorptive paints could be limited to three days per weex for continous operation. Our contamination problem would then be considered of nuisance value rather tnan a real bealth tezerd. 7. Decontamination For operational decontazination it sees feasible to sugzsat tne nationally, accepted tolerance limit of 300 miliiroentgsens per week as a guide to decontamination lavels for innabited areas. Areas exceeding this linit wuld require decontamination before continuous habitation would be permitted. U. S. Naval Radiological Safety Regulations (1951) specify that final clearance for vessels is set at 15 aillircentgons per day (105 apr/week). In genural thie licit will be rusched by tho tine tho contaminated veesals have completed roll-up operations, with tha possible excoption of concauntrated contacination of water systams and underwater growths. The concentrated contazination aay require do- contamination by disassembly of water systames and removal of sine scale. 8. Health dazards Radiological hazarda ofO,eration Castle will be sinilar to tnose of previous Eniwetok operations but more extansive due to tha nature of the detomations. The axtont and intensitica of radioactive fali- out will be dependent oa the cotecrological conditions at the tine of detonation. Tiere can be no assurence tnat sano of the fall-out will ast land oa inhabited areas or on ships of the Task Fore>. If this does happen, it crsates an annoying situstion, but in all procs~ bility not one which can be regarded as truly hazardous, dszards fron radiation Both external and intornal will be confined to imoedi-ta areas of detonation. Radiation tolerance Linits will Licdt working tine in some othur orcas. Radiation levels st grxumd level within a mile of the detcnation will be extremely hazardous during the first twelve hours.. sadiatisna decay aay be expected to. follow an approximte 1/T relationsnip. adLoactive lagoon dilution can also be expected to follow an approxi-~ mate 1/T relationship. This would mean that lagoon contamination at a single spot on the second day would be 1/k tnat of the first day, on the third day 1/9 thit of the first day,