1946-09-05 – Report of INSPECTION FOR RADIOACTIVITY of the USS LAFFEY (DD724) at the San Francisco Naval Shipyard

Navy Reports that document the dumping of nuclear waste directly into San Francisco Bay as well as other Navy Bases, the orders, correspondence, etc.

Citation: OPERATION CROSSROADS, RADIOLOGICAL DECONTAMINATION OF TARGET AND NON- TARGET VESSELS Part 2 pp. 5-7

[Note all page numbers and notes will be enclosed in these brackets]

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REPORT. H.Q, 1

EXPERIMENTAL WORK, SAN FRANCISCO NAVAL SHIPYARD SAN FRANCISCO, CALIF.

Report of INSPECTION FOR RADIOACTIVITY of the USS LAFFEY (DD724) at the San Francisco Naval Shipyard, 5 September 1946

The USS LAFFEY DD724 was subjected to an inspection for radioactivity on 5 September 1946 at the San Francisco Naval Shipyard. The inspection, witnessed by representatives of the 12th Naval District and the Western Sea Frontier, was conducted under the supervision of Captain W. E. Walsh (MC) USN. Other members-of the inspecting party were:

Dr. Robert A. Newell – a radiologist from Stanford University
Dr. F. H. Rodenbaugh – radiologist, San Francisco
Wayne A. Chadbourn, Lieut. – (MC) USN

The necessary coordination between the Shipyard personnel and the inspecting party was maintained by Lieut. Comdr. M. E. TURNBAUGH, USN, Ass’t. Repair Supt. (Hull), San Francisco Naval Shipyard.

No official conclusions were arrived at upon the completion of the inspection since samples of scale and other foreign matter still had to be subjected to laboratory analysis. Unofficial opinions of the inspecting party indicated that the USS LAFFEY was not what might be termed a “hot” ship and, hence, might be considered safe working area for Shipyard personnel with a few restrictions on the work that might be carried on. These restrictions were imposed as extra safety measures pending the outcome of laboratory reports and further study of the results of the inspection by the members of the party.

The LAFFEY was in Floating Repair Dock, ARD #32 at the beginning of the inspection. Prior to the start of pumping operations, samples of the water around the LAFFEY were tested for radioactivity

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with negative results. At the start, it had been intended to raise the vessel in increments of about three feet, monitoring the area in each increment as it was uncovered. This plan was discarded and it was decided to pump the dock dry and monitor the hull of the LAFFEY from beneath, working upward as necessary on staging.

Pumping operation commenced at 0930 and was secured at 1040. During this period, Shipyard personnel assigned to assist the inspection party were lectured to by Lt. Comdr. Turnbaugh and Lieut. Chadbourn. The basis of these lectures were explanations of what was to be done and why. This was done to eliminate any questions in the minds of the men as to the safety precautions to be carried out in order to protect themselves from radioactive particles, and, also, to assure them that no great mysterious danger faced them. Previously, each man to participate in the inspection had been equipped with canvas suits, canvas shoes, socks, underclothing, gloves and hard hats. The final instruction was a warning to be sure and prevent any small radioactive particles from entering body thru mouth, nose or open wound.

At 1130 the monitoring party descended into the dock and started a survey of the ships bottom using Geiger counters. Particular attention was paid to areas covered with marine growth or in areas of rust.’ The readings obtained at this point indicated that the radioactivity of the hull was considerably below the dangerous level; hence, no further measurements on the outside hull were necessary. Sample scrapings of the bottom growth were collected in buckets and monitored.

The individual members of the inspection party took samples for laboratory analysis and a large supply of the scrapings were packed in cans for shipment to Navy Dept., Washington, D. C. It is to be noted here, that despite the warning by the inspection party to the Yard workers not to handle scrapings without gloves, the members of the inspection party did not observe this precaution themselves.

After the outside hull inspection was completed, the evaporator in the Forward Engine Room was opened and the First Effect tube nest was pulled out. A large piece of canvas was spread below it on the deck, and, after flushing down in order to keep dust to a minimum, the scale on the tubes was chipped off. During the actual chipping process, all personnel, except the chippers and Dr. Newell, left the Engine Room. The chippers

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were outfitted with oxygen masks for protection of the respiratory system. Dr. Newell wore a canister mask for about twenty minutes in order to have a contaminated canister for laboratory analysis.

A section of four inch salt water piping was removed from the sea suction to the evaporator distiller pump for analysis at the University of California Radiation Laboratory. Suitable blanks were provided for the pipe system from which the section was removed, and, also, the specimen itself was properly tagged to insure its return to the vessel.

The results of those tests indicated that the salt water systems were considerably more radioactive than the outside hull plating, but still not to the degree that would be unsafe for Shipyard personnel during Yard overhaul.

Following the above tests all workmen who had participated in the inspection were lined up and Geiger Counter Monitored. The results of this monitoring indicated no appreciable radioactivity, so the men were released to turn their clothes in to store for future use if necessary.

Three items that had been used in the inspection were found to be radioactive; these were the piece of canvas, a foxtail brush and a hard bristle brush. These three items had been used for collecting samples of chipped scale from the evaporator tube nest. These three articles were encased in cement and prepared for disposal at sea, preferably in water of a depth of at least 1,000 fathoms. 

As a final precaution, until the inspection board granted a definite clearance to the vessel, the hull was wet down four times a day while in dock. This was done to prevent radioactive dust particles from being blown around the Shipyard by the wind.

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