explosion, the ship was reboarded at H+3 hours and pronouncedradiologically clear. All indications were that the damage to the USS Bladen was very light. A few screens and windows were blown in but that was about all. The second bomb test was the larger of the two. The Navy has also reported that a thorough review of available records has failed to disclose any dosage of radiation received by the veteran other than that incident to medical and diagnostic procedures. , Medical Evidence: The veteran’s service medical records did not report any complaints, symptoms, treatments or findings which were diagnostic of a malignant lymphoma. Normal findings were recorded on his discharge following the atomic test. In this connection, the record does not precisely establish the extent of radiation dosage received by the veteran at the time of Operation Crossroads. The Navy has reported that they conducted a thorough review of available records but their search did not disclose any record of radiation dosage other than that incident to medical and diagnostic procedures. Nevertheless, the record is not entirely devoid of information on this matter. The extracts from the deck logs of the USS Dawson and USS Bladen are pertinent and helpful. It is noted that the USS Dawson was reboarded on the day after thefirst atomic test and it was declared safe. It does not appear that he reboarded this ship after the second explosion on July 25, 1946. The examination in February 1949. Generalized lymphoma was diagnosed while USS Bladen, to which the veteran was assigned on August 19, 1946 was pronounced radiologically clear only three hours after the second atomic disease was a direct result of atomic radiation, that it was probable that the issued on August 27, 1946. The significance of this radiological clearance veteran was hospitalized in April 1963. The physician who made the diagnosis of lymphomastated at the time that it was his considered opinion that the disease had been present a long time. In January 1966 veteran was again hospitalized and he died in March. An autopsy report disclosed that the lymphosarcoma was generalized and was manifested in bone marrow and lymph nodes. The BVA certified two questions to the Armed Forces Institute of Pathology for review and opinion: 1. Whether or not lymphoma and lymphosarcoma are caused by ionizing radiation. 2. Whether there is a reasonable expectation that sufficient radiation was received under the circumstances of duty on board the Bladen to cause detectable changes in the veteran’s tissues. test on July 25. A radiological clearance certificate was subsequently is that it effectively rebuts the contention of the veteran that he was exposed to prolonged radiation while he remained aboard the USS Bladen. However, apart from the evidence which establishes that the veteran was not exposed to a prolonged period of atomic radiation, the Board now has the benefit of the cited opinion from the Armed Forces Institute of Pathology. This opinion presents two material conclusions. The first is that no direct relationship has been currently established between malignant lymphoma (lymphosarcoma) and ionizing radiation. The second is that the veteran did not receive sufficient radiation while in service to cause detectable changesin his tissues. TheInstitute responded, as follows: Because of the therapy this man received, it is not possible to document the presence of malignant lymphoma in the necropsy material although the chances observed in the sections of the lymph nodes and spleen are consistent with the appearance of malignant lymphoma following therapy. The cause or causes of malignant lymphoma (lymphosarcoma) remain unknown at this time and no direct relationship between malignant lymphoma (lymphosarcoma) and ionizing radiation has been established in man. We are also of the opinion that the patient did not receive sufficient radiation while on duty in the service to cause detectable changes in his tissues. Findings of the BVA and Basis for Decision: In finding that the veteran’s malignant lymphoma, first manifest about 14 years after service, was not present during service and was not etiologically related to any exposure to ionizing radiation during service, the Board said: The essence of the veteran’s claim was that he had been exposed to radiation on board the USS Bladen for a prolonged period of time in addition to any exposure which may have been caused by his assigned duties during the decontamination of his ship after he reboarded it 98 99