ATTACHMENT 13 OPERATION TEAPOT 1955 LOGO United States Atmospheric Nuclear Weapons Tests Nuclear Test Personnel Review Prepared by the Defense Nuclear Agency as Executive Agency After the aircraft landed, project personnel held standard gamma survey meters near the contaminated surfaces to determine their radiation intensities. Several types of meters were used and their readings were compared. After the initial surface contamination studies, Project 2.8a personnel evaluated the decay of radioactivity on the aircraft in two ways. Aircraft were resurveyed periodically over the next two days to assess the rate of decay, and project participates attached film to contaminated areas of the aircraft with masking tape to assess the accumulation of radiation exposure. The film was removed for analysis within 24 hours after the detonation. The last phase of Project 2.8a was a study of project personnel involved in making the film surveys described above. Some participants placed film over the hands and fingers of their gloves while they performed the radiation survey work. The film was then removed, developed, and evaluated to assess accumulated dose to ground-crews working on contaminated aircraft. Another technique was to have the project personnel rub the base of their hands over the surface of an aircraft with known contamination. An autoradiograph of the hand was then made by placing the hand on a large x-ray film packet for a period of time and then developing the film to observe the image created. In this way, changes in the contamination patterns of aircraft and relative amounts of contamination transferred to the hand could be measured. While conducting these studies, none of the survey team exceeded the AFSWC maximum permissible exposure of 3.9 roentgens for ground crew personnel (80). Project 2.8b. Manned Penetration of Atomic Clouds, was a study to measure the radiation dose rate and dose received by air crews flying near and into the nuclear cloud. As indicated above, the same aircraft may have been used as for Project 2.8a. Specific information was sought by the Air Force on radiation dose rates inside the cloud, the total dose received during 96 passage through the cloud, and the dose received on the return flight. In addition, it is likely that lead vests were also tested for their effectiveness in shielding the crew against radiation. Seven aircraft penetrations were made through the nuclear clouds of five detonations, which ranged in yield from eight to 30 kilotons. Project personnel instrumented F-84s, B-36s, B-57s, and T-33s to measure gamma radiation dose rates. All instrumentation was prepared and checked for proper operations on the day before each shot. Typically, two automatic recording dose-rate meters were used in each aircraft. One was mounted in the nose compartment, and the other in the rear of the cockpit. A non-recording meter for use by the pilot was also installed in each aircraft. In addition to the dose-rate meters, a number of film devices were used. National Bureau of Standards film packets were placed in the cockpit and nose of each aircraft near the recording dose rate meter to determine accumulated radiation dose at the recorders during the mission. The pilot of each aircraft was accompanied by a technical observer in all aircraft but the F-84, which had a maximum crew of one. Pilots and technical observers wore film badges issued by the Radiation Safety Division of the AFSWC 4926th Test Squadron. The pilot and technical observer also carried a number of small pieces of Dupont dental x-ray film. One special film pack was designed to measure internal body radiation dosage. This film packet consisted of nine small disks of film enclosed in a watertight capsule attached to a string. The capsule containing the film was swallowed by the technical observer and the pilot prior to take-off and retrieved after the flight was completed. A similar capsule containing film was attached to the outside of the pilot's flight suit near his stomach. The pilot and the technical observer wore lead vests to reduce radiation exposure to the body (46: 112: 284: 306). 97 Typically, the aircraft left Indian Springs AFB before shot- time, climbed to an altitude of about 40,000 feet, and flew to a position about 48 kilometers east of the ground zero to observe the detonation and the subsequent development of the nuclear cloud. The aircraft then flew by the cloud to estimate the time required to fly through the most dense section of the cloud. The aircraft then flew through the cloud. The technical observer, who had a stopwatch, recorded the time of entry into and exit from the visible cloud. In addition, an automatic dose-rate recording meter was also used to measure time in the cloud. After emerging from the cloud, the aircraft returned immediately to Indian Springs AFB, and the crew and instruments were removed from the aircraft. Crew members left the aircraft by climbing onto a forklift, which lowered them to the ground. They were then decontaminated. A description of these procedures is found in section 5.3 of this volume (46; 80; 306). For these missions, the Test Manager authorized a special exemption to the radiation exposure limit for four Project 2.8b Air Force officers. Each officer was authorized to receive a total of 15 roentgens whole-body gamma radiation during participation in the project (285). 4.1.3 Program 3: Effects on Equipment and Structures The purpose of Program 3 was to document blast and shock effects of nuclear detonations on vehicles and buildings. The nine projects conducted under Program 3 during TEAPOT were considerably reduced from the extensive testing conducted during UPSHOT-KNOTHOLE and focused on assessing the destructive characteristics of the precursor zone of the blast wave. The program included tests on vehicles placed near ground zero and on a variety of concrete and steel structures, including ILLEGIBLE ground shelters. The data from these projects were used to assess the damage potential of nuclear detonations on large, fixed targets and rigid structures. 98 GRAPHIC FIGURE 4 FITZSIMONS ARMY HOSPITAL DENVER, COLORADO (B) FOR REFERENCE SEE (6bb06) 8 FIGURE 5 WALTER REED ARMY MEDICAL CENTER WASHINGTON, D.C. (D) FOR REFERENCE SEE (6bb07) 9 GRAPHIC SECRET - RESTRICTED DATA ATOMIC ENERGY ACT OF 1954 FIGURE 6 TINKER AIR FORCE BASE OKLAHOMA CITY, OKLAHOMA (M) FOR REFERENCE SEE (6bb08) 10 GRAPHIC FIGURE 7 HILL AIR FORCE BASE OGDEN, UTAH (N) FOR REFERENCE SEE (6bb09) 11 GRAPHIC FIGURE 8 SCOTT AIR FORCE BASE BELLEVILLE, ILLINOIS (O) FOR REFERENCE SEE (6bb10) 12 GRAPHIC FIGURE 9 CAMP MERCURY, NEVADA (X) FOR REFERENCE SEE (6bb11) 13 GRAPHIC c. Shot dates and yields are as indicated. d. Physical fallout data were obtained from Eisenbud and are represented as curies per square mile of gross fission activity. It is emphasized that these values do not include iodine activity. Moreover, in most cases, the data were collected on a daily basis; therefore, the absence of a bar does not imply zero activity, but rather that the amounts were less than 50 curies per square mile. The data presented in Figures 4 through 9 would appear to demonstrate: a. Reasonably good correlation between the combined weather- yield data and iodine excretion. The passage of the cloud is in most cases followed by elevated iodine levels and larger rises usually follow clouds produced by shots of higher yields. The validity of this correlation is strengthened when one considers the converse of the above; namely, absence of clouds generally accompanies low iodine levels. b. There is an apparent lack of correlation between the combined weather-yield data and physical fallout measurements. This cannot be explained at this time. c. There is an apparent lack of correlation between urinary iodine and physical fallout measurement. This implies that the physical measurements, as currently determined, do not reflect the total biological hazard. These attempts at correlation of the various factors are admittedly incomplete and are based on data which in fact measure different isotopes, namely, iodine and gross fission activity exclusive of iodine. Since there is no known evidence of significant iodine fractionation or separation from total fission activity, it was thought that the physical and biological measurements do represent part of the same problem and therefore should correlate generally with weather-weapon data. Estimation of Biological Hazard. An accurate calculation of radiation dosage to the thyroid (the critical organ for iodine) obviously cannot be made from weekly determination of the urinary activity. However, it is believed that an estimate of exposure to an "average" individual at a given station may be useful, particular for a comparison with maximum permissible exposure levels referable to currently accepted medical concepts, and with values previously referred to as measured by Cronkite and Bremman in connection with Operation Castle. The estimate to total thyroid dose was made according to calculations presented in detail in Appendix C-1. For the "average" individual at Fitzsimons Army Hospital, Figure 4, an integrated total of 0.011 roentgen equivalent physical (rep) was delivered to the thyroid throughout the entire test period. This may be compared to an integrated 14 total of 24 rep from a 10-microcurie tracer dose as commonly utilized in medical clinics. A 33 per cent uptake by the gland is assumed. Thyroid Glands Of the 46 thyroid glands examined, only two showed appreciable activity above background. One thyroid from a patient who had been living in Chicago showed some 0.2 microcurie on 15 June and a second thyroid showed an activity of 0.005 microcurie on 30 June. The decay of these samples was followed to definitely establish the identity of the activity as iodine-131. Correspondence disclosed that the Chicago patient received 45.9 microcuries of iodine-131 on 31 May 1955 and death occurred 1 June 1955. The Letterman Army Hospital patient was a retired soldier who returned to the hospital only during his terminal illness. No accurate record to establish isotope therapy in this case over the 9-month period preceding death is available. There was no record of radioactive iodine during his terminal illness. Background Variation A comparison of background count and iodine recovery from samples collected at Walter Reed Army Hospital, Washington, D.C. is shown in Figure 10. The initial level of urinary activity, i.e., less than 2 counts per minute, is within the error resulting from counting periods necessarily of short duration. The general correlation is apparent. During the period 8 February through 24 May a standard potassium-40 sample maintained a stable counting rate above background. This is very suggestive of air contamination and, in part, supports the thesis that in man inhalation is an important route of entry for fission products. Strontium-90 The strontium activity measured in the combined urine specimens is indeed low. The processing methods used permit the measurement of 2 dpm of yttrium-90 (strontium-90). This represents approximately 1 x 10-c microcuries. Values obtained which might be considered maximum apply to the total urinary excretion for the "average" individual during the entire test series: Scott Air Force Base (Bellville, Ill) 30 x 10-6 microcuries Fitzsimons Army Hospital (Denver, CO) 24 x 10-6 microcuries Tinker Air Force Base (Oklahoma City, OK)30 x 10-6 microcuries These figures are considered conservative with respect to hazard since samples which contained greater than average iodine activity were processed. Details of this calculation and additional values for strontium-90 are noted in Appendix C-2, Table 1. During the decay studies, the presence of other relatively long half-lived isotopes was studies, the presence of other relatively long half-lived isotopes was noted, but these were not identified. The activity about equaled that of the strontium. Subsequent re- milking removed these isotopes. 15 FIGURE 10 COMPARISON OF BACKGROUND COUNT AND IODINE RECOVERY AT WALTER REED HOSPITAL FOR REFERENCE SEE (6bb12) 16 Relationship Between Strontium and Iodine A comparison of iodine and strontium excretion as measured in urine was undertaken to ascertain whether any functional relationship indeed prevailed. We were prompted to make this comparison when the data established the presence of higher amounts of strontium when higher amounts of iodine were found. There are no known data available for man relating to an acute strontium exposure problem such as that available for iodine-131 where inhalation is considered a primary route of entry. The data in Figure 11 illustrate actual observations for iodine versus strontium in the same pooled specimens. The activity of iodine has been corrected in Figure 12 to time of detonation relating each component of the pooled specimen to a specific shot and subsequent cloud passage over the station. The accuracy of weather data for a specific shot limits the confidence in a precise correction factor. These decay-corrected data appear to define a reasonably direct relationship between iodine and strontium. The practical considerations implied by this statement require further verification and delineation at future nuclear tests. In order to evaluate the measured levels of iodine versus strontium activity, a thoretical approach was used. If one accepts the assumptions that strontium and iodine are produced in essentially equal mass amounts at the time of fission, and that the intake and excretion components in man for these elements are essentially the same for an acute exposure, then the amounts of each isotope expected in the urine can be calculated. The biology of strontium is not known for man; however, gross iodine kinetics are well established. Available excretion and retention data from animals* suggest that urinary strontium and iodine kinetic are somewhat analogous. Therefore, it is perhaps not unreasonable to expect that for a given ratio these isotopes would appear in essentially the same ratio in the urine. Based on the above, it is calculated that 750 dpm of iodine should be expected for each dpm of strontium. Measured values give an average iodine to strontium ratio for 576, as determined by the "best drawn" line of Figure 22. Considering the approximations required for the derivatives of the theoretical ratio, as outlined in Appendix C-3, there is excellent agreement between the calculated values and those actually measured. In fact, the data indicate that somewhat more strontium was found than would be expected. The apparent, although not verified, explanation is that additional strontium was available through ingestion. ________________________________ *"Biological Hazards of Radioactive Strontium" by Vaughn in Biological Hazards of Atomic Energy by Haddow - Oxford 1952. 17 FIGURE 11 RELATIONSHIP BETWEEN I131 AND Sr90 ACTIVITY --- (UNCORRECTED DATA FOR POOLED SPECIMENTS BY WEEKS AND STATIONS) FOR REFERENCE SEE (6bb13) GRAPH 18 FIGURE 12 RELATIONSHIP BETWEEN I131 AND Sr90 ACTIVITY --- (CORRECTED DATA FOR POOLED SPECIMENTS BY WEEKS AND STATIONS) FOR REFERENCE SEE (6bb14) GRAPH 19 IV. Conclusions The practicability of conducting a world-wide human sampling program for urinary iodine-131 and strontium-90 was established. Utilizing low-level counting technics and routine chemistry, it was possible to measure physically significant levels of both isotopes. Valuable biological data were obtained as base line information for the spring 1956 tests at Eniwetok, and in addition, certain worthwhile biological implications became apparent. A heretofore unmeasured, acute inhalation strontium problem is discussed. Through the use of methods employed in the project, relatively reliable hazard predictions for acute exposure to iodine and strontium in man might be derived. In order to derive actual hazard values, however, additional specific information on strontium-90 kinetics in man is imperative. The data indicated a possible direct relationship between iodine and strontium activities in the urine. If this is verified and the ratio delineated at a future test, it might be possible to estimate the acute strontium hazard by the measurement of urinary iodine alone. In addition to the above, three quarters were raised that required further consideration: (1) The relative contributions of the acute (inhalation) and chronic (ingestion) exposure to the total biological hazard. (2) The relationship of physical fallout and biological data. (3) An evaluation of the contribution to the total biological hazard of other long half-life fission products. 20 Acknowledgment This report would not have been possible without the wholehearted cooperation of many individuals. Colonel R. P. Mason, MC, Chief of Research and Development Division, Army Surgeon General's Office, and Lt. Colonel S. E. Lifton, MC, Air Surgeon General's Office, arranged for the collection of specimens. The Commanding Officers of the Medical Units and the men involved were particularly conscientious. Lt. Colonel J. T. Brennan, MC, WRAE, contributed valuable advice and encouragement throughout the project. Colonel Roy D. Maxwell, MSC, Armed Forces Special Weapons Project, aided the inception of the project and contributed technical advice for the chemical procedures. Mr. Marrill Eisenbud and Dr. John Harley, New York Operations Office, Atomic Energy Commission, provided the physical fallout data. Dr. A. Machta and Mr. R. List, United States Weather Bureau, provided the cloud trajectory data. Dr. Gustave Klinck, Armed Forces Institute of Pathology, arranged for the human thyroid gland analysis. Drs. Howard Andrews, National Institutes of Health, and A.K. Solomon, Harvard Medical School, kindly reviewed portions of the report. Valuable technical assistance during the project was made by Cpl. John Landgraf, Pvt. William D. Cash, Pvt. James F. Keegan, Pvt. Robert Troiano and Pvt. Royal Merritt. 21