Light continues to be shed on questions surrounding Bikini Incident

by Kenji Namba, Senior Staff Writer

On March 1, 1954, the United States conducted a nuclear test, code-named “Bravo,” on the Bikini Atoll in the Pacific Ocean. Two weeks later, the radiation exposure of the Daigo Fukuryu Maru (The Lucky Dragon No. 5), a Japanese tuna fishing boat, was revealed. That September, the boat's chief radio operator, Aikichi Kuboyama, who was 40 years old at the time, died of radiation sickness. Fifty-seven years have passed since then, but further light has been shed recently on the “Bikini Incident,” as it has come to be called. The Chugoku Shimbun posed the question of the significance of the incident to two experts on the subject: Masatoshi Yamashita, 66, executive director of the Kochi Prefecture Pacific Ocean Nuclear Test Suffering Support Center, who has traced a total of 1,000 Japanese fishing boats with links to the incident over the course of 26 years, and Seiichiro Takemine, 34, a researcher at Mie University, who is familiar with the circumstances of the Marshall Islands, the site of the U.S. nuclear tests.

“The greatest contamination of the environment in human history”
Masatoshi Yamashita, executive director of the Kochi Prefecture Pacific Ocean Nuclear Test Suffering Support Center

Many people see the Bikini Incident as an event of the past. But such a view trivializes the incident.

According to documents issued by the government at that time, as many as 992 Japanese fishing boats were forced to dispose of their tuna catch due to their exposure to radiation. When another 14 boats, which were also exposed to the radioactive fallout but did not dispose of their tuna catch, are included, the total tops 1,000 vessels.

Only the Daigo Fukuryu Maru returned directly to Yaizu Port in Shizuoka Prefecture after being exposed to the hydrogen bomb test. The crew had understood the danger of their situation and it was determined that they were suffering from acute radiation sickness. Other boats, though, which were also exposed to radiation, were not aware of what had happened and they continued fishing in that area.

Between March 1 and May 14 of that year, the United States conducted a total of six nuclear tests on Bikini Atoll and the Enewetak Atoll. This series of nuclear tests was dubbed “Operation Castle.” The destructive force of the Bravo bomb tested on March 1 is, alone, 1,000 times as powerful as that of the atomic bomb dropped on Hiroshima. The more such tests were conducted, the more contaminated the air and the ocean became.

Incident was closed after “political settlement”

The crew members of the boats that continued to operate in the area washed their bodies, rinsed their rice, and cleaned their dishes with rain that was contaminated with radiation. It's possible that they suffered internal exposure to radiation from eating contaminated fish.

These boats were forced to dispose of their contaminated tuna, a total of 486 tons of fish, when they returned to their home ports in Japan. The crew members were more or less left unattended and were simply told to “wash off their heads,” or something to that effect. The Japanese government bowed to the wishes of the United States and ended their investigation into tuna contamination by the end of that year. With a consolation payment of 2 million dollars (720 million yen) from the United States, the whole matter was deemed resolved in January of 1955. The incident was closed as a result of a “political settlement.”

Later surveys that followed the crew members who were exposed to radiation have found that many of them died of cancer, heart attacks, and other maladies, and poor health among the surviving men is conspicuous, too.

Contamination spread to the United States

In the spring of 2010, we discovered new information regarding the radioactive fallout of Operation Castle on the website of the U.S. Department of Energy, which is in charge of nuclear weapons development in the United States. The document reveals that the agency had measured the amount of ash that fell as a result of six detonations between March and June 1954. These measurements were conducted at 122 locations around the world and taken at the same time. The document indicates the number of atoms that decayed in a minute on self-adhesive films of one square foot (about 0.09 square meters). Among the worldwide locations were Misawa, Tachikawa, Kadena, and Kikaijima, places in Japan where U.S. military bases are located, as well as Hiroshima and Nagasaki, the home of the Atomic Bomb Casualty Commission.

Over the course of four months, the radioactive fallout spread from the Marshall Islands to locations west and east. The fallout to the east reached as far as the United States and Mexico. The fallout that arrived on U.S. shores was five times the amount that reached Japan. In 1954, the Tokyo Metropolitan government made a map that showed the locations of the boats during their voyages in the Pacific. Evidence of radiation exposure was found on these vessels after they returned to Tokyo ports. When the map showing their locations is compared to a map which depicts the radioactive isoplethic curve, similar to a contour map, it is clear that the Japanese fishing boats were exposed to radiation.

I suspect that Operation Castle brought about the greatest contamination of the environment in human history. The Bikini Incident, an incident that demonstrates the horror of nuclear weapons and global contamination, has still not been fully illuminated.

Profile:Masatoshi Yamashita
Masatoshi Yamashita was born in 1945. He was formerly a high school teacher. In 1985, while leading a group called the “Hata High School Seminar” in Kochi Prefecture, which was designed to engage the community in research of modern Japanese history, he encountered crew members of the tuna fishing boats who were exposed to radiation in the Bikini Incident. Since that time, Mr. Yamashita has been pursuing follow-up investigations of the boats and the people concerned.

“There are clearly other hibakusha”
Seiichiro Takemine, researcher at Mie University

The Marshall Islands were used as a nuclear test site by the United States between 1946 and 1958. A total of 67 tests involving atomic and hydrogen bombs--23 tests on the Bikini Atoll and 44 tests on the Enewetak Atoll--were conducted during this period. The destructive force of these bomb tests is equivalent to over 7,000 Hiroshima atomic bombs. I can't help but wonder how much radioactive material released by these tests was spread into the atmosphere.

Regarding the Bravo test in 1954, the United States admitted that the four areas of Bikini, Enewetak, Rongelap, and Utirik are sites that suffered nuclear damage. The United States then paid 150 million dollars and said that the problems it caused were “completely resolved.” So as we investigate the effects of the nuclear tests on the Marshall Islands, we need to look closely at the areas beyond those four sites of Bikini, Enewetak, Rongelap, and Utrōk. We also need to look closely at all the nuclear tests that were made, not merely the Bravo test.

Joining in the people's lives to pursue research

I have visited the Marshall Islands seven times since 1998 to pursue research concerning the effects of the nuclear tests on the lives of local residents. In Japan, I often hear such sentiments as “Japan is the only nation to have suffered nuclear attack” and “Nagasaki must be the last place to ever suffer the effects of radiation,” but in fact, since the atomic bombing of Nagasaki, other places have suffered radiation exposure, too. My travels have taken me to islands which lie outside of the area which the United States admitted suffered exposure to radiation and I've listened to the voices of the people there by joining in their lives. Those people are hibakusha, too, survivors of nuclear tests.

Since then an official document on the subject has been found. The document, which has been held by the U.S. Department of Energy, states the names of areas that could have been affected by “significant radioactive fallout” from the nuclear tests on the Marshall Islands. The document is dated June 23, 1973, though the name of the person who made the document is unknown.

In this document, along with the four areas which the United States had already acknowledged, such place names as Ailuk, Likiep, Wotho, and Kwajalein are given. According to the document, a total of 14 areas were exposed to radioactive fallout of a medium degree or higher. It also mentions the possibility of radioactive fallout caused by the nuclear tests conducted in 1952 and 1958 reaching Ponape, a city in the heart of the neighboring nation of Micronesia.

These admissions demonstrate that beyond the areas that the United States has acknowledged, there are clearly other hibakusha who have suffered from the aftereffects of their exposure to the radiation from this series of U.S. nuclear tests. 

Depleted uranium shells used as well

Nuclear tests have not been conducted on the Marshall Islands since 1959. But a U.S. missile test ground is still located on Kwajalein. Since 1961, when the test ground was employed as an impact site for intercontinental ballistic missiles, missiles have been launched from Vandenburg Air Force Base in California, approximately 8,000 kilometers away, which target the lagoons of Kwajalein. Some of these missiles have missed their targets and landed on nearby islands.

According to a newspaper issued in Hawaii and dated July 1, 1982, as well as Hiromitsu Toyosaki, a Japanese journalist, missile tests using depleted uranium shells have also been conducted.

We must understand the totality of nuclear damage in the world through the lens of “global hibakusha.” Nuclear abolition must be manifested as an actual political agenda, not merely a slogan that is shouted out.

Profile:Seiichiro Takemine
Seiichiro Takemine was born in 1977. He has been engaged in research involving the Marshall Islands since he was a university student. In 2004, Mr. Takemine founded the Global Hibakusha sub-committee of the Peace Studies Association of Japan and currently serves as co-chair of this sub-committee. His publications include “Hidden Hibakusha.”

Radiation exposure equivalent to radius of one kilometer from Hiroshima hypocenter
Shoji Sawada, professor emeritus of Nagoya University

According to new material concerning Operation Castle, which involved U.S. nuclear tests in the Marshall Islands in 1954, the accumulated count of radioactive fallout in the most affected area was upwards of 200,000 per minute per square foot. In that area were five fishing boats, including the Daigo Fukuryu Maru. In a lesser affected area, where the count reached between 100,000 and 200,000, were seven boats, including the Daini Kosei Maru.

Among these vessels, I chose three boats from Kochi Prefecture, including the Daini Kosei Maru, and compared the incidence of deaths due to cancer in connection with the crew members with that of Hiroshima A-bomb survivors. While the annual incidence for A-bomb survivors who were exposed to the bombing within a radius of one kilometer from the hypocenter was 0.504%, that of the victims of Bikini was as high as 0.615%, 2.00%, and 0.650% with regard to those respective three boats. Although we must take into account the lack of statistical precision, I suspect that the victims of Bikini were exposed to radiation that is equivalent to the exposure received by A-bomb survivors who were located within one kilometer from the hypocenter in Hiroshima.

(Originally published on March 21, 2011) 

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