Operation Castle: a Radiological Safety Nightmare

[This is a response to]... a statement from the official Operation CASTLE history published by the Defense Nuclear Agency that "It is clear at this time HQJTF 7 did not know where the [BRAVO] cloud was, nor where it had been. There was apparently no great concern..."

Neither had BRAVO cloud passage over inhabited Rongelap Atoll and weather station on Rongerik had been noticed. At Rongerik twenty-five Air Force and three Army personnel operated an ionospheric sounder. A low-level strip-chart fallout monitor had been left there by AEC personnel with instructions to communicate an alert if the recorder went "off scale" at O.1 R per hour. A message was sent at 3:15 p.m and received by the Army communications center at Enewetak at 3:47 p.m for retransmittal to HQJTF 7. Whether the message was transmitted or not, command was unaware of Ronkerik's fallout problem.

After Rongerik personnel changed from short to long-sleeved shirts and long pants as a precaution, they continued routine duties, except they observed fallout particles under a microcope and noted they made a cathode ray tube glow. In addition, they watched fallout particles gather to a depth of one-quarter to one-half inch outside and noted a visible layer on tables in the mess hall and barracks.

Meanwhile, those ships southeast of ground zero experienced more fallout of finer particles, begining about 1:00 p.m. and stopping at midnight, Washdown systems and fire hoses again were activated. Also by midnight, Air Force task group officers finally became aware of a potential fallout problem at Rongerik. A seaplane reached Rongerik by midmorning with an Air Force rad-safe officer taking readings in the air and on the ground. Readings were high, 1.2 R per hour indoors on a bed and 24 R per hour on sand outside. Eight of the garrison fit in the seaplane and they left for Kwajalein. The remaining twenty were evacuated that afternoon. Original exposure estimates were 85 R for the first eight men and 95 R for the rest.

Exposure estimates based on four film badges worn and eight placed about the station ranged from 40 to 98 R. The DNA dose reconstruction contractor reduced the external doses to a range of 32 to 98 R. The DNA dose reconstruction contractor reduced the external doses to a range of 32 to 52 rem in 1987. The first group of eight personnel arriving at Kwajalein had seven to eleven showers and the second group had five each to remove radioactive contamination up to 0.25 R per hour from the skin. Radiation levels changed little after the first set of showers. Those who required the repeated showers apparently did not realize that internally deposited radioactive material will not wash off.

Because Rongelap Atoll was closer to BRAVO than Rongerik and could have received more fallout, the rad-safe officer who returned by seaplane with eight Rongerik personnel soon radioed his commanding officer. "Suggest immediate survey of inhabited islands of Rongelap. High possibility exists that immediate steps must be taken to evacuate natives". An air survey indicated 7 R per hour on the ground which further calulated to a preliminary theoretical exposure of 340 R if islanders continued to live there.

Evacuation of Rongelap and nearby Ailingnae, where some natives had gone fishing, began the next morning. A seaplane left for Kwajalein with the sixteen people who seemed most ill, while sixty-six more left on the destroyer Philip. Another destroyer Renshaw, was sent to Uterik, 150 miles east of Rongerik and 300 miles from BRAVO to evacuate natives there, who would have received a calculated 58 R if they remained. One hundred fifty-seven natives were removed the next morning. Four hundred and one Ailuk Atoll natives were not evacuated because they would receive less has 20 R, the permitted exposure for cloud sampling pilots. On that basis, the natives were not considered threatened with radiation injury. Drinking water samp- les from Rongelap and Uterik indicated radiation levels from two to twenty-eight times task force allowed amounts of contaminants.

To say that Shot BRAVO seriously disrupted the rest of Operation CASTLE is a considerable understatement. Physical damage and radioactive contamination of Bikini test facilities meant converting land-based to ship-based operations, includeing living arrangements. Attendant difficulties were personnel transport, communications, equipment handling and severe boating conditions during unfavorable weather conditions (and a new more cautious task force and commander), rearrangement of shot sequences, and changes in predicted yield took their toll in deterioration of test stations caused by salt spray, humidity, and sun and contributed to a hectic remaining test operation.

The second test in CASTLE was shot ROMEO, detonated on a barge in the BRAVO crater with a yield of 11 Mt on 27 March 1954. Task Force Commander Clarkson had voiced a familiar refrain about avoiding danger to other populated areas of the Pacific, but managed to keep his promise for a change. Required weather conditions were much more stringent. This time, four search aircraft were in the air two hours before shot time flying parallel courses to cover a wide area ahead of the cloud to the north over open ocean. Lessons had been learned from BRAVO, albeit at a very high price in damage, radiation exposure, and suffering, both immediate and in the future.

The remaining four shots of CASTLE were fired without serious incident, although the stiffer weather requirments caused delays resulting in the last shot being fired 14 May 1954 instead of the planned date of 22 April. BRAVO remained a disaster that could have been a great deal worse. The sixty-six Rongelap natives, fortunately for Clarkson and the task force, had gathered at their home island of Rongelap in the southern part of the Atoll, after witnessing BRAVO and the unusual phenomena of visible light, huge dark cloud, and audible shock, to discuss the frightening things they had seen and heard. If they had stayed at their northern food islands, near the hot line of the BRAVO cloud, their assigned exposures of 175 R would have been about ten times or more greater, well beyond the 100 percent lethal range, taken to be 600 R in 24 hours.

In addition, thyroid doses from exposure to radioiodines, assigned later, were in the range of 1,400 rem. Most of the natives with high thyroid doses have developed thyroid problems. One young person died of leukemia but insidious secondary diseases, usually considered normal and not radiogenic, but developing from effects of low thyroid hormone levels, could have taken a greater toll had medical care not been provided to the natves for the rest of their lives.

One Japanese fisherman died on 23 September 1945 as an indirect cause of his exposure to BRAVO fallout. He acquired hepatitis from blood transfusions used in his hospital treatment. The remaining fishermen were in the hospital for fourteen months before recovering, at least for the time being, from their radiation exposures. Abnormal white blood cells remained for more than 20 years as testimony to their near-lethal radiation exposures. Amount of radioiodine exposure to their thyroids is unknown but might roughly be estimated by comparison with the Rongelap natives. No information has surfaced on diseases secondary to thyroid exposure.

Rongerik servicemen were followed medically for some time, with no obvious radiation exposure effects, and were released back to normal duty. It is doubtful that these men were medically followed for any lung or lymph node exposure diseases, much less the more insid- ious diseases which could result from thyroid damage, even though the measured after-shower radioactivity indicated thyroid exposure to radioiodines. The same applies to military personnel on ships exposed to fallout after BRAVO, even though personnel on Bairoko and Philip had external beta burns and crew members of Patapsco had fairly large and sustained unprotected exposure to BRAVO cloud. The practice of analyzing urine samples to detect exposures of natives and servicemen to internally deposited fission products and plutonium was inadequate and of little use. Few fission products from nuclear detonations appear in the urine of exposed personnel, isotopes of iodine do, being in soluble form, but they have short half lives, the longest of note eight days. Most fission products and plutonium from nuclear testing are deposited in the lungs as oxides, may migrate and collect in lymph glands, and do not appear in the urine in measurable amounts. In retrospect, analysis of fecal samples would have been a method of detecting radionuclide oxides coughed up from the lungs or elevated by ciliary activity swallowed, and excreted.

Who was responsible for the near-fatal exposures, beta burns, over-exposures, and consequences of long-term effects of exposure to radiation from BRAVO? Cancers with very long latent periods, thought by many scientists to be caused even by low radiation exposures, insidious secondary diseases that might result from thyroid exposure, nonmalignant lung and heart diseases associated with lung exposures, and blood diseases resulting from migration of radioactive particles to the mediastinal lymph nodes from the alveolar sacs of the lung, could occur long after exposure to BRAVO fallout. The person responsible was Maj. Gen Percy Clarkson, Joint Task Force 7 Commander. With command comes responsibility, usually. In this case, Clarkson was not punished or even reprimanded, but was allowed to continue in command having learned how to conduct a thermonuclear test operation at the expense and suffering of many others.