The Invisible Rain — The Sea Where Ashes of Death Fell, and a World Awakened

The history of nuclear weapons cannot be told through the flash that fell on two cities alone. Throughout the Cold War, the nuclear powers led by the United States and the Soviet Union repeated an enormous number of nuclear tests to verify the power of new weapons. In deserts, underground, and in the southern seas. With each explosion, invisible particles were lifted into the sky, carried by the wind, and eventually fell back to earth as rain or ash.

People called it the ‘ashes of death.’ Harm that quietly eroded human beings in places that were not battlefields, in an age that was not war. In this installment, we trace with respect what this invisible rain brought about, and how people around the world rose up against it. The starting point of the story is the spring of 1954, at a single atoll in the Pacific.

A Giant Fireball Rising into the Bikini Sky

Not long after the Second World War ended, the United States chose Bikini Atoll in the Marshall Islands of the Pacific as a nuclear test site. And in the early morning of March 1, 1954, the Bravo test of ‘Operation Castle’ was carried out there.

What detonated was a hydrogen bomb. Its power is recorded as being in the range of more than ten megatons, roughly a thousand times that of the atomic bomb dropped on Hiroshima. This output far exceeded the United States’ initial expectations, and because the design estimate had been too optimistic, the damage is said to have spread all at once. A massive crater roughly two kilometers in diameter and tens of meters deep was gouged into the seabed.

The problem was not its scale alone. The coral-reef sand lifted by the explosion took on intense radioactivity and rained down over a wide expanse of sea as a white powder. Downwind were residents of nearby islands and fishing boats at work. Without knowing what it meant, they came to be bathed in the falling white ash.

The Lucky Dragon No. 5 — A Boat That Returned, and One Death

At the time of the Bravo test, a Japanese tuna fishing boat was at work on the sea roughly a hundred-some kilometers from the point of detonation. It was the Daigo Fukuryu Maru, the Lucky Dragon No. 5, with its home port at Yaizu in Shizuoka Prefecture.

The crew saw the dawn sky glow strangely red toward the west. Before long, a white powder began to fall from the sky. Without knowing what it was, they continued fishing while bathed in the ash, and returned to Japan. The twenty-three crew members who came home developed one symptom after another that appeared to be radiation injury: burn-like skin abnormalities, hair loss, fatigue.

And in September of that same year, Aikichi Kuboyama, who had served as the radio operator, passed away. His name is remembered deeply as an event symbolizing the harm caused by the ashes of death. Later investigations further revealed that the Lucky Dragon No. 5 was not the only fishing boat affected; it became clear that several hundred vessels in total had been operating in the same waters. Radioactivity was detected in the tuna that had been landed, and the markets fell into confusion. A test in a distant southern sea had struck directly at Japan’s dinner tables and daily life.

Ash That Fell on Lands Around the World

The harm from fallout was not the Pacific’s alone. Nuclear tests under the Cold War were being repeated on vast tracts of land in many countries as well.

Within the United States, atmospheric nuclear tests were conducted at a test site set in the Nevada desert. The radioactive material produced by the explosions flowed on the wind toward downwind regions and is said to have rained down on nearby villages. People who were thus exposed during their own country’s nuclear development came to be called ‘downwinders,’ and links to the onset of leukemia, thyroid cancer, and other illnesses have been pointed out. Yet rigorously proving the causal connection between each individual illness and exposure, one by one, is difficult, and it is said to be a point on which even researchers’ assessments diverge.

In the Soviet Union, too, the situation was grave. Around the Semipalatinsk Test Site in the Kazakh region, years of nuclear testing are reported to have exposed many residents to fallout, with cancer, thyroid abnormalities, and other health harms spreading. There are various estimates of the number of people affected, and one cannot simply assert a single figure, but it is thought that a considerable number of residents were affected.

Across positions and borders, nuclear testing quietly demanded a price from the people who lived there. We must look at this fact without forgetting respect for those who were harmed, yet without exaggerating the numbers or the causation.

People Who Raised Their Voices Against the Invisible Rain

The exposure of the Lucky Dragon No. 5 moved Japanese society greatly. Anxiety and anger over the ashes of death soon spread into a nationwide signature campaign. And in August 1955, the first World Conference against Atomic and Hydrogen Bombs was held in Hiroshima. Many participants gathered from several countries, and the call for a world without nuclear weapons took shape through the hands of ordinary citizens.

Looking to the world as well, there was a major movement in that same year. In July 1955, the philosopher Bertrand Russell and the physicist Albert Einstein, among others, jointly issued a manifesto warning of the danger of nuclear weapons. This was the Russell-Einstein Manifesto. Among the signatories were leading scientists of the day, including Hideki Yukawa. This manifesto became a catalyst, and in 1957 scientists gathered in Pugwash, Canada, beginning the Pugwash Conferences to discuss nuclear weapons and the responsibility of scientists.

That the very scientists who had been on the side of building the weapons warned the world of their danger. That citizens who had been harmed joined hands across borders. Into the anti-nuclear movement flowed the feelings of many different people from differing positions. Of course, the idea that nuclear deterrence itself protects peace also existed from that time, and the voices demanding abolition and the voices supporting deterrence would go on to coexist for a long time afterward. In viewing this history, we should be cautious about declaring that only one side is right.

The experience of the ashes of death confronted the world with the fact that the power of the nuclear can harm people not only in the instant of war, but also through tests in peacetime. The memory of each person who was harmed, and the voices of those who rose up in protest, became the foundation supporting the subsequent current of nuclear disarmament.

Yet even after a treaty to reduce the ash falling from the sky was made, the nuclear warheads piled up on the ground continued to increase. A mountain of nuclear weapons that had swollen large enough to destroy humanity many times over. To truly reduce it required long and arduous negotiations in which the United States and the Soviet Union faced each other head-on. Facing a swollen mountain of nuclear weapons, the end of the Cold War finally opens the door to disarmament.