The Lucky Dragon No. 5 in the Daigo Fukuryu Maru Exhibition Hall in Tokyo.

The Lucky Dragon No. 5 in the Daigo Fukuryu Maru Exhibition Hall in Tokyo.
28 February 2018

How the unlucky Lucky Dragon birthed an era of nuclear fear

David Ropeik

David Ropeik

David Ropeik is an instructor in the Environmental Management Program of the Harvard Extension School, a consultant in risk communication, and author of How...


Yumenoshima Park on a drizzly November day is a dreary place. It sits on an artificial island made of waste and landfill along one of the drainage canals that empty into Tokyo Bay, in Koto, a neighborhood in the Japanese capital that doesn’t show up on any must-visit lists. Hundreds of thousands of people visit the famous Tsukiji fish market, a couple miles to the west, every year. Millions visit Tokyo Disney, a couple miles the other way. But few visit the Daigo Fukuryu Maru Exhibition Hall, a small A-frame building tucked in a corner of the park. More might, if they understood the significance of the weathered 94-foot long fishing boat on display inside.

The Lucky Dragon No. 5 looks odd sitting indoors, resting on the concrete floor supported by red metal posts under dim lighting. A ladder on the starboard side lets you climb up and peer at her deck and wheelhouse. Peer, and ponder what it must have been like on the morning in 1954 when the vessel bobbed in the Pacific Ocean near the Marshall Islands, and the sky in the west burst into eerie orange, like a bright sudden dawn, followed by a roar and a violent rush of waves. Ponder what the 23 crew members thought when a ghostly white rain, thick with ash, started to fall, coating them and their catch. Ponder how profoundly the strange and frightening events that morning shaped so much of the world we now live in.

Just before dawn on March 1, 1954, most of the crew of the Daigo Fukuryu Maru were below deck asleep, having worked overnight at the grinding labor of long-line tuna fishing. Yoshio Masaki, the ship’s fishing master, was on deck, and later recorded in his log the frightening things he saw and heard: “Suddenly the boat has been surrounded by a bright light. Such an early dawn is impossible. Makes feel something very dangerous.” Another crewman wrote “Oh. What is that!? Shocked! Suddenly all over the west direction, as if having been inflamed, became deep and bright like sunrise. Terrible!” Masaki wrote, “nine minutes later a roaring sound arrives like overlapping avalanches. Bang, bang, bang, bang—an awful sound like the Marshall Islands are sinking as angry waves into the sea.”

The crew raced to the deck. Someone yelled “atomic bomb!” Fear raced through men who just a few years previously had been combatants in World War II, men who knew about Hiroshima and Nagasaki. They searched for the mushroom-shaped cloud they had seen in pictures of those bombings. They scanned the sky for planes and the horizon for ships.

But what they had witnessed was far more than a Hiroshima-style atomic bomb. The glow and shock wave came from the test detonation of a thermonuclear weapon, a new version of mankind’s most powerful tool of war. The test was code-named Castle Bravo, and it had gone frighteningly wrong. The bomb turned out to be more than twice as powerful as its designers predicted, and while the Lucky Dragon was 86 miles from the test site and outside the officially declared warning zone, it was well within the range of the bomb’s impact.

The crew returned to work hauling in their catch, but as they watched, strangely layered circles of clouds slowly spread from the direction of the explosion. Then it started to rain. Pelting white rain, driven by suddenly howling winds that the US meteorologists assigned to the bomb test had predicted would blow the other way. The unnatural rain coated the ship and crew with a gritty ash that stuck to the men’s hands, necks, faces, and hair and got in their mouths and eyes. It painted the dark blue tuna on the deck a ghostly grey.

The rain and ash fell on the Lucky Dragon for five hours. By the time it subsided, some of the crew were dizzy, vomiting, or had fevers. They had been covered in, swallowed, and inhaled the highly radioactive remains of corals incinerated by the immense nuclear explosion, the powdery remnants of which had been thrown into the sky and then rained back down across a vast area of ocean. By the time they got back to port two weeks later, most of the crew were suffering from headaches, bleeding gums, skin burns, and hair falling out in clumps. All the men were hospitalized.

Operation Ivy. The Japanese media devoted extensive coverage to the plight of the Lucky Dragon. The Yomiuri Shimbun reported “Japanese fishermen encounter Bikini A-bomb explosion test. 23 men suffer from A-bomb disease.” Within days the international press was covering it too.

Though the world already knew that high levels of radiation had caused what was then known as “atomic bomb disease” among survivors of the weapons dropped on Hiroshima and Nagasaki, that illness was associated with the radiation generated at the moment the bombs exploded. Japanese medical investigators found that in this case, the men of the Lucky Dragon No. 5 were suffering from something else, an illness experts labeled “acute radiation disease” that was caused not by the bomb but the radioactive rain it produced. The Japanese began calling this rain shi no hai, death ash. The media, and the world, quickly began calling it by a new name that within weeks joined the global lexicon of fear: fallout.

Japan, which for years had honored but also stigmatized and avoided the hibakusha, citizens from Hiroshima and Nagasaki who survived the atomic bombs, now poured out sympathy for the Lucky Dragon crew and outrage at the United States for once again victimizing Japan with atomic weapons. “We are not guinea pigs!” wrote one newspaper.

Just days after the Lucky Dragon returned to port, a Japanese town passed a resolution against the use of atomic bombs. That action was widely reported and within weeks such resolutions were adopted across Japan, and within a few months, around the world. The first “World Conference Against A and H bombs” was held the following summer, in Hiroshima. This was fully nine years after such bombs had been used. It wasn’t the World War II bombings but the Lucky Dragon No. 5 that finally triggered the world-wide call to ban the bomb, the first truly global protest movement of the modern era.

The Daigo Fukuryu Maru also peeled away the cloak of secrecy surrounding the US nuclear weapons testing that had been going on in the Pacific for eight years. The US military had made an hour-long film, Operation Ivy, focused on the 1952 test of a nuclear bomb nicknamed “Mike.” The film was made for internal use only, and when President Dwight Eisenhower saw it, he was so shaken that he ordered it kept secret, afraid it would terrify the public—as it ultimately did. Within two weeks of the Lucky Dragon’s return to port, with the world now aware of the tests and pressuring the American government to open up, the film was released to the public.

The first 50 minutes of the film, about technical preparations for the test, look like the stuff of standard military public relations. But at minute 54:39, everything changes. There is a final silent moment as we watch the bomb drop. Then it goes off, and the terrifying destructive power of thermonuclear weapons, which the world had never seen, becomes frighteningly real. With a roar accompanied by ominous music, the massive fireball lights the sky like a false sun, and a towering mushroom cloud slowly surges high into the atmosphere. This dramatic sequence goes on with no narration for nearly two minutes.

The film then shows just how massive the fireball was by overlaying it on the skyline of Manhattan. Over more ominous music the narrator says, “the fireball alone would engulf about one quarter of the island of Manhattan.” Then there is a sequence showing the Pacific island on which the test was conducted, and the gaping ocean-filled crater that was all that was left of the island and surrounding reef after the explosion. A map of Washington DC is shown, and the narrator says, “with the Capitol at point zero there would be complete annihilation” for three miles in all directions.

These six brief minutes of film, released as a result of the Lucky Dragon incident, terrified the world. Operation Ivy played repeatedly on US television stations, and within days was being shown in dozens of countries. People already knew about atomic weapons and the Cold War, but the film made them aware that thermonuclear weapons posed an existential threat to life on earth.

The Lucky Dragon created new fears in other ways as well. News coverage showed the contaminated tuna the boat had brought in. Japanese health authorities ordered tests on any fish caught in a 2,500-kilometer radius around the bomb test site. Thousands of samples were radioactively contaminated.

Officials at the US Atomic Energy Commission, which shared authority for the test program, tried to play down the risk, but food companies around the world shut off fish imports from Japan. And the media reported that the radioactive cloud from an atmospheric nuclear bomb test rose so high into the stratosphere that winds carried the fallout around the world. Many soon believed that the threat was not just to a few unlucky Japanese fishermen, but that potentially dangerous radioactive rain could ultimately fall everywhere, on everyone, endangering the whole world’s food and water.

The Lucky Dragon incident helped spread widespread fear of nuclear radiation into popular culture. The radioactive monster Gojira (known in subsequent Western films as Godzilla) rose from the sea on Japanese movie screens in the fall of 1954, just months after the Daigo Fukuryu Maru affair. In the original film, the crew of a fishing ship sees a strange orange underwater glow, recoils in terror at a blinding flash, and all that’s left is the charred hull of the empty ship bobbing in the waves. An ancient monster stirred to life by an immense human-made explosion then tramples an island village, leaving radioactive footprints. The beast attacks Tokyo, a strange electric glow lighting up along his spine just before he blows steamy radioactive breath that sets anything on fire.

Screenwriter Ishiro Honda, who had earlier started to make a more conventional monster movie, later wrote that he was inspired to change the film by the Daigo Fukuryu Maru incident, and that he “took the characteristics of an atomic bomb and applied them to Godzilla.” The version shown in the United States two years later (adapted to be less anti-American) featured a radio journalist (played by Raymond Burr) watching the radioactive monster destroy Tokyo and telling his audience “I’m saying a prayer, a prayer for the whole world.” The message was clear. The terrifying risk from nuclear weapons and radioactive fallout was global.

The modern genre of mutants-caused-by-radiation movies quickly sprang up. Some books and sci-fi movies had already touched on radiation fears, but now the subject exploded into all forms of popular culture, and the radiation-zapped monster remains a mainstay bogeyman in films, books, and visual art. The fear was born as the “death ash” rained down on the crew of the Daigo Fukuryu Maru. A plastic Godzilla toy stands over the bookshop at the museum that houses the vessel’s remains.

The birth of modern environmentalism. The death ash played a huge role in creating the environmental movement as we know it. American biologist Barry Commoner, one of the founders of the movement to reduce air and water pollution from industrial chemicals, initially focused on the global environmental threat of radioactive rain. In 1956, Commoner was one of 24 Washington University scientists calling for a halt to atmospheric testing of nuclear weapons because of the threat it posed to human and environmental health. In 1958 he helped found the Greater St. Louis Committee on Nuclear Information. In the late 1950s, he helped run a study that documented trace amounts of a radioactive isotope in thousands of children’s baby teeth, the result of nuclear tests. Commoner would later say that the US government’s secrecy and dishonesty about the dangers of nuclear-weapon testing motivated him to act on environmental issues. “The Atomic Energy Commission turned me into an environmentalist,” he said in a 1993 interview.

In 1960, Rachel Carson published Silent Spring, a foundational work in the establishment of modern environmentalism. Most people see the book as a cry against the indiscriminate use of DDT and other industrial chemicals, but the global threat of radioactive fallout also helped inspire her to write it. “In this now universal contamination of the environment,” she writes, “chemicals are the sinister and little-recognized partners of radiation in changing the very nature of the world—the very nature of its life.”

The central case made in Silent Spring, and by environmentalism generally, is that for all the benefits modern human-made technologies offer, they can also endanger the natural world. That belief profoundly shapes public attitudes and behaviors about a wide range of issues to this day. We have come to fear, not without reason, that the remarkable technological progress the world has enjoyed since World War II comes with frightening risks. Our threat perception has been shaped by Commoner, Carson, and the environmental movement they helped created. The Daigo Fukuryu Maru was the match that lit the fuse.

The danger from fear itself. Six months after the Lucky Dragon returned to port, Aikichi Kuboyama, the ship’s radioman, died. The official cause of death was liver failure, from which he had been suffering for years. But it was clear that radiation had weakened his immune system so much that that was what actually killed him. “Has the death of a citizen ever been watched by so many eyes?” asked the Asahi Shimbun newspaper. “They are the eyes of a strong anger and protest against the ‘ashes of death.’” Edward Teller, one of the brilliant people who developed the hydrogen bomb, commented dismissively that “it’s unreasonable to make such a big deal over the death of a fisherman.” How arrogant he was, and how utterly ignorant and mistaken. Kuboyama’s death was a big deal. Nuclear radiation was a killer. (The rest of the crew survived but suffered life-long health problems associated with prolonged exposure to such high doses.)

The Japanese word for fear is kyoufu. Ironically, while the modern world’s kyoufu of radiation essentially began with the Lucky Dragon incident and Kuboyama’s death, another Japanese experience—the atomic bombings of Hiroshima and Nagasaki—has taught us that radiation is nowhere near as dangerous as we have come to assume. A total of 86,600 hibakusha have been followed with regular medical examinations for 71 years and compared to 23,000 Japanese who were not exposed to radiation. It stuns most people to learn this (it sure stunned me), but the overall increased radiation-induced cancer death rate among atomic bomb survivors—thousands of whom instantly received high doses of radiation from the bombs themselves, then experienced extended exposure to fallout in their air, water, and food—is less than one percent. “Atomic bomb disease” has killed a total of only 586 of those 86,600 survivors. At lower but still substantial doses –doses far higher than those caused to the public by the nuclear accidents at Chernobyl in 1986 or Fukushima in 2011—radiation has caused no change in disease rates compared to the normal rates among the control population. The children of the hibakusha have also been followed and studied, and show no multi-generational genetic damage passed down from their parents, though children born to pregnant women among the hibakusha did suffer a higher rate of birth defects. (The 70-plus year-long study of the atomic bomb survivors continues, conducted by the Radiation Effects Research Foundation in Hiroshima.)

Based on this hard-won knowledge, experts can say with confidence that the increased lifetime cancer mortality rate from Chernobyl will be just 3 to 4 percent above normal cancer death rates for the affected population, according to a 2006 World Health Organization study. The Fukushima nuclear accident is unlikely to raise the rate of any disease associated with radiation above normal. The doses to which people were exposed at Fukushima were nothing near those experienced by the hibakusha closest to the blast in 1945, and nothing like the intense doses received by the crew of the Lucky Dragon.

But though the information from health experts is reassuring, fear of radiation from Fukushima persists. It persists in the tens of thousands of people evacuated as a precaution when no one knew what was going to happen, who now won’t move back even though radiation doses are low enough in most areas to allow them to safely do so. Families and entire communities have been decimated. Rates of unemployment, alcoholism, depression, and stress-related illnesses are elevated compared to other areas of Japan. As was sadly true for the hibakusha before them, some children from Fukushima prefecture are shunned and stigmatized when they travel.

The fear persists across Japan, where sales of agricultural products from the Fukushima prefecture are lagging, echoing past fears of contaminated tuna from the Lucky Dragon, even though we now know that the actual risk from the infinitesimal doses around Fukushima is practically zero.

It persists with the hundreds of billions of yen being spent to collect water running through the Fukushima Daiichi nuclear plant site. The water picks up a radioactive molecule called tritium, which the world’s top experts all agree causes such a low dose to anyone exposed that it poses no threat to human health. (Some of the red and green exit lights in theaters, designed to stay on when the power fails, are filled with tritium.) Japanese authorities will probably release all that tritium-tainted water into the ocean. Though this would pose no threat to the environment, the very idea is facing fierce resistance, fed by excessive fear of anything connected to the word “radiation.”

Finally, kyoufu of radiation persists across Japan and elsewhere in the form of opposition to nuclear energy. Nuclear power produces neither greenhouse gasses, which contribute to climate change, nor particulate pollution, which sickens or kills tens of millions of people around the world every year. Having shut down its nuclear power fleet because of fear of radiation following Fukushima, Japan is now burning more fossil fuels to produce electricity, contributing to short- and long-term health threats that are vastly greater than those posed by radiation. (So is Germany, and so are several US states.) Due to fear of radiation, some Japanese don’t want to allow TEPCO, the electric company, to restart their Kashiwazaki Kariwa nuclear complex, where millions have been spent upgrading safety since Fukushima. Without revenue from that plant, TEPCO has to continue to borrow Japanese taxpayer money to pay for the clean-up at Fukushima, a multibillion-dollar effort to capture radioactive material that experts agree poses no threat to public or environmental health.

The fact that deep nuclear fear has persisted for so long, despite solid evidence that the risk isn’t as great as we thought it was back in 1954, is perhaps the Daigo Fukuryu Maru Exhibition Hall’s most profound lesson. The museum helps us understand the events and historic context that gave birth to our fear of radiation, and why it is so deeply engrained. It helps us realize how fear with such deep emotional roots is not readily overcome by objective consideration of the facts alone. It helps us see how easily fear can overpower reason, even when fear of a risk does more harm than the risk itself.

Fortunately, the museum also offers a cause for optimism. It suggests that with time, we might be able to put old fears in new perspectives. The curator of the Daigo Fukuryu Maru Exhibition Hall is Ichida Mari. When I visited recently I asked her what visitors to the museum say about Fukushima. She said there is still plenty of worry, but things seem to be changing. “At first after Fukushima people were feeling a lot more fear about it,” she said, “but in the past three years, that fear and concern has decreased, and at the same time there has been a sense of increased knowledge about radiation.”

Knowledge—based on history, scientific research, and experience—can help people in Japan and elsewhere move beyond their fears of radiation. Research on the psychology of risk perception has found that emotion and instinct play an oversized role in shaping our fears, and that once learned, those fears stubbornly resist change. But the research has also found that knowledge and time help give objective reasoning more influence over emotion as we make our choices and judgments about risk.

Knowledge from this obscure but immensely important little museum, plus knowledge from the study of the hibakusha, plus the amount of time that has passed since the Chernobyl and Fukushima disasters (31 and six years respectively) with no large death toll from either, might shift society’s thinking about radiation. In that way, the Daigo Fukuryu Maru Exhibition Hall offers reason for hope.