In the cryogenic silence of frozen biological material stored in her radiation lab, Dr. Ayumi Hida hears a lesson for the nuclear age: “The atom bomb must not be used ever again.”
Hida is the Nagasaki chief of clinical studies for the longest continuous health survey in history, a remarkable effort begun days after the destruction of the cities of Hiroshima and Nagasaki. Her work has helped to establish that Japanese people still suffer—physically, mentally, and socially—from two atomic bombs dropped, as of August 2025, eighty years ago.
As Japan marks these anniversaries on August 6 and 9, decades of medical exams by Hida and her colleagues at the Radiation Effects Research Foundation (RERF), along with evidence from its massive collection of preserved blood and tissue, have revealed that the nuclear genie unleashed in 1945 is still at work.
Jim Carrier
Dr. Ayumi Hida, chief of clinical studies at the Nagasaki laboratory of the Radiation Effects Research Foundation, tracks the long-term effects of the 1945 bomb.
RERF has found in Japan’s bomb survivors new cancers, heart and immune problems, strokes, inflammation, leukemia, and even a form of cataracts—atop the usual maladies of old age. With a mean age of eighty-five, their ranks dropping by some 6,000 a year, 106,825 Japanese atomic bomb survivors—known as hibakusha, a term meaning “bomb-affected people”—also suffer from post-traumatic stress.
“They say, ‘I have an atomic bomb nest in my body,’ ” Dr. Masao Tomonaga tells The Progressive. Tomonaga, eighty-two, a hibakusha himself, cares for 400 survivors in a nursing home.
“The human consequences of the atomic bombs have not ceased,” he has written. “Many people are still dying of radiation-induced malignant disease. Therefore, it is too early to finalize the total death toll. Hibakusha have faced a never-ending struggle to regenerate their lives and families under the fear of disease.”
Honored for their anti-nuclear activism—the national Japanese hibakusha group known as Nihon Hidankyo won the Nobel Peace Prize in 2024—their unique stories describe what it was like to live through the only nuclear attacks in history. In Hiroshima and Nagasaki, where peace is a subject taught in schools, hibakusha speak regularly, so much so that students sometimes complain that they’ve heard it before.
Every living hibakusha is a walking laboratory, an experiment in the human effects of nuclear war. It is this story that is now emerging from long-term studies. “Fat Man,” the plutonium bomb dropped on Nagasaki on August 9, 1945, killed 73,000 of the city’s 240,000 citizens, either instantaneously or by the end of 1945, with a combination of blast wind, thermal burns, and radiation—or, in some cases, all three. Fat Man’s twenty-one-kiloton yield surpassed the Hiroshima uranium bomb’s fifteen kilotons, but its effect was partially shielded by Nagasaki’s hilly Urakami River canyon over which it exploded.
Jim Carrier
Dr. Masao Tomonaga, an eighty-two-year-old physician and bomb survivor who cares for 400 bomb survivors, says radiation from the 1945 blast is still killing them because of genetic mutations.
Six hundred yards from ground zero on the day of the blast, Nagasaki’s medical college and hospital lost half of its staff and students, but the survivors set up first-aid stations within days. The injuries they saw ranged from embedded glass to ruptured intestines to carbonized skin flash-burned by the radiation. Tomonaga wrote that “according to the saddest memory of some survivors, the blast wind tore off the heads of babies who were being carried on their mothers’ backs in the traditional Japanese way. Most of the mothers also died.”
By that September, U.S. Army, Navy, and Manhattan District teams, with doctors, pathologists, and physicists, arrived together with occupying forces. Their mission was driven, largely, by a desire to understand the bomb’s effects and how the United States could protect itself from a nuclear bomb in the future. At the time, radiation was a new and mysterious force, and discoveries were mostly classified. Information about radiation and anything related to the bombings would be censored in the Japanese media until 1952.
Within weeks, however, the effects of the radiation began to show up in individuals—loss of hair, bloody diarrhea, peeling skin. Autopsies were performed and organs—such as hearts, lungs, eyes, brains—from hundreds of victims were taken to the U.S. military’s Institute of Pathology in Washington, D.C., where, in a secret, bomb-proof laboratory, the effects of high radiation were studied, analysis that helped create the guidelines and warnings for radiation exposure used worldwide today. The last organs, slides, and tissues were returned to Japan in 1973.
On October 12, 1945, General Douglas MacArthur ordered the merger of Japanese and American medical studies on the bombings under the leadership of sixty American and more than ninety Japanese physicians and scientists. The Joint Commission for the Investigation of the Effects of the Atomic Bombs evolved, in 1975, into RERF, with labs in Nagasaki and Hiroshima. It is supported by the Japanese government and with $14 million annually from the U.S. Energy Department’s Office of Environment, Health, Safety and Security.
In 1950, Japan identified 94,000 bomb survivors and a control group of 27,000 people who were not exposed to the bomb, and began a lifetime epidemiological study of cancer and causes of death. Of that initial group of survivors, 25,000 adults are still being followed closely as they age for signs of any effects of radiation.
Every day at the RERF lab in Nagasaki, five of these patients arrive for their two-year screening. Blood is drawn, urine is collected, they are given a physical, and quizzed about their medical history and lifestyle. Living cells are stored in liquid nitrogen tanks—to date 2.3 million tubes of blood are stored there, Hida reports. Serum, plasma, and urine are put in freezers. The lab also holds half a million paraffin blocks of tissue and nearly one million autopsy and surgical slides, some dating back to 1945, she tells The Progressive. RERF is also following 77,000 children of bomb survivors and 3,600 people who were in their mothers’ wombs at the time when the bombs exploded. These efforts have helped RERF to identify three chronological phases of atomic bomb casualties.
Jim Carrier
Liquid nitrogen tanks at the Radiation Effects Research Foundation in Nagasaki hold millions of blood and tissue samples from atomic bomb victims at a temperature of -321˚ Fahrenheit.
By 1949, 210,000 survivors thought to be in relatively good health began to encounter the first signs of malignancy—leukemia, caused by radiation’s damage to blood cells. Cases in children and adults four-to-five times greater than those not exposed rose until 1955, and leveled out for a decade after that.
Around 1960, solid cancers began to appear, their numbers peaking in 2000 and remaining at that level since, Tomonaga reports. They included lung, breast, thyroid, stomach, colon, liver, skin, and bladder cancers. Some patients had three to five different cancers—all originating independently, rather than metastasizing from a source organ.
The third phase, evident now, includes a second wave of leukemia called myelodysplastic syndrome. This development, which occurs in the elderly at a rate of four times that of the general population, indicates that damaged cells in the bone marrow of children in 1945 have survived for more than seventy years in their bodies. Tomonaga’s hypothesis is that stem cells, which are designed to generate replacement cells in their host organ, “eventually transform to malignant cells” when gene abnormalities accumulate. In essence, they become tiny cancer factories, Tomonaga tells The Progressive. “It can be said that the atomic bomb is still killing some hibakusha.”
Statistically, 46 percent of leukemia deaths and 10 percent of solid cancer cases in Japan between 1950 and 2000 are attributable to the bomb’s radiation.
It is also known that Nagasaki’s plutonium bomb was inefficient—only one of the six kilograms of plutonium exploded—leaving most of its atoms intact. Plutonium particles, with a half-life of 24,000 years, have been discovered in lake bottoms, in spots where black rain fell ten to fifty miles from the hypocenter, and in the lungs and bones of people who died soon after the bombing. It’s possible, Tomonaga has written that the plutonium particles “continue to emit alpha rays intermittently and injure lung cells nearby, causing lung cancer.” This potential has yet to be studied.
As Japan recovered from World War II, hibakusha were shunned and discriminated against by non-bomb-affected families who feared that the hibakusha’s exposure to radiation would be harmful to them and their offspring. This belief arose from the many cases of miscarriage, deformities, and stillbirths of babies who were in utero when the bomb exploded, amid a long-held cultural embrace of purity and distaste for pollution.
This stigma remains today. Some survivors won’t apply for hibakusha certificates or take part in medical studies for fear of being labeled as untouchable. RERF reports that its studies have found no statistical proof that radiation damage has been passed to subsequent generations, but the suspicion is still widely held. For its part, RERF has been criticized for its practice of researching without treating, and has never completely shaken its early reputation treating hibakusha as guinea pigs.
Not until 1957, after lobbying by the newly formed Nihon Hidankyo and public outcry following the 1954 hydrogen bomb tests in the Marshall Islands that drenched Japanese fishermen aboard the Lucky Dragon No. 5, killing one of them, did Japan’s parliament approve free medical care for hibakusha. Because of restrictive requirements, only a small number were eligible at first. The Atomic Bomb Survivors’ Support Law was broadened in 1995.
In 2014, Japan officially recognized 192,719 living persons as hibakusha. Some 119,169 had been directly exposed to the bomb. The total includes 45,260 who were exposed by entering the cities shortly after the bombings, 20,939 who helped in relief or burial activities, and 7,351 unborn children of mothers who were exposed. With certificates issued by the government, they get free health care, a monthly stipend of a few hundred dollars, and payment of their funeral expenses.
A hibakusha certificate is granted, generally, if the person was within a zone of estimated radiation. The first zones in Hiroshima were concentric circles around ground zero. Nagasaki’s is an irregular shape. When they tell their stories, Nagasaki hibakusha pull out a map and point to the spot where they were on the morning of August 9.
The size and shape of that zone have been disputed by subsequent research. After noticing a cluster of cancer patients in his medical clinic, Dr. Kohya Honda and Nagasaki University environmental researcher Toshihiro Takatsuji found plutonium and cesium deposits near the Nishiyama reservoir that were ten to thirty times higher than elsewhere in Nagasaki. Combing through oral histories, they found 900 reports of fallout and have mapped hot spots outside the official Nagasaki zone.
Jim Carrier
Dr. Kohya Honda, left, and researcher Toshihiro Takatsuji have mapped plutonium fallout hot spots miles outside the officially recognized Nagasaki hibakusha compensation zone.
The Japanese government is trying to prevent the expansion of Nagasaki’s qualifying zone because it could weaken support for nuclear power, the researchers tell The Progressive during a visit to the reservoir. They estimated that the expansion would also add about 5,000 people as official hibakusha.
In Hiroshima, a “black rain” fallout survey was successful in granting a larger hibakusha certification area. But as far away as thirty kilometers, Nagasaki’s fallout, largely dry, could still have contaminated food or water, says Masato Ohya, an emeritus professor at the Nagasaki Institute of Applied Science. “Even those who were outside the designated area inhaled a lot of nuclear particles. And that affected people’s bodies through internal exposures.”
Because today’s nuclear weapons are almost all plutonium-triggered bombs, they could leave unexploded plutonium particles, too. “So, the Japanese and U.S governments want to underestimate the potential of damages caused by their weapons,” Ohya says. “That’s why the voices of those outside the designated area have been neglected.”
Japan’s support for hibakusha is not universal, either. Envy and discrimination still exist, to the point where some hibakusha refuse to take part in the RERF research for fear of being publicly exposed and shunned, Dr. Hida says.
Perhaps because Nagasaki’s business district was not destroyed by the bomb, perhaps because many of the dead were bulldozed into mass graves without identification, perhaps because of its long history as Japan’s first open international port—a story represented in the opera Madame Butterfly—and perhaps because Hiroshima was bombed first, Nagasaki has never made the atomic bomb the center of its cultural history, in the opinion of professor M.G. Sheftall, a U.S.-born academic who has lived in Japan since 1987 and authored two new books on Hiroshima and Nagasaki.
Still, there is an unpretentious recognition of the city’s atomic history and its effort to promote peace. “The keyword from Nagasaki people is that Nagasaki should be the last,” says Tatsujiro Suzuki, president of Peace Depot, a think tank focusing on peace studies. “When I came to Nagasaki years ago, I suddenly came to a town where everybody believes that nuclear forces can be abolished,” he tells The Progressive. “If you walk down the street, the people I meet, most are related to hibakusha, so no one is separate from the experience.”
Jim Carrier
The thirty-two-foot-tall bronze Peace Statue by sculptor Seibo Kitamura (1884-1987) in Nagasaki’s Peace Park. Seibo wrote of the statue: “The right hand points to the atomic bomb, the left hand points to peace, and the face prays deeply for the victims of war.”
After the war, Nagasaki remodeled the area around ground zero—a destroyed Christian, working-class neighborhood—into a compact peace zone. On the north end, a broad plaza is dominated by sculptor Seibou Kitamura’s bronze Peace Statue of a figure pointing up to the bomb with the other hand reaching for peace. The plaza is filled daily with school groups and tourists from cruise ships.
At the other end of the plaza is a peace fountain and an open park with Fat Man’s hypocenter marked by a tall shaft. Nearby, the Atomic Bomb Museum conveys a blunt history, with graphic photos and artifacts. One cannot miss the photo of a boy lying on the ground, entirely carbonized. Exhibits near the museum’s exit remind visitors of the awesome growth of nuclear weapons worldwide in the years since 1945. Japan, forbidden by its constitution from having a military, relies on the United States for its deterrence, which explains its ironic refusal to sign the Treaty on the Prohibition of Nuclear Weapons.
Adjacent to the museum is the cathedral-like National Peace Memorial Hall, which holds a record of every known person who died from the two bombs. Each year on the anniversary of the bombings, the names of new victims are added. The toll, as of last year, was 198,785.
Jim Carrier
The atomic bomb called “Fat Man” exploded 1,600 feet above this hypocenter marker in the city of Nagasaki, Japan, at 11:02 a.m. on August 9, 1945. It obliterated a working-class Catholic community.
Eighty years ago, six days after the Nagasaki bomb was dropped, President Harry Truman asked the U.S. military to carry out a survey of the Japanese bombing. Much like the one conducted in Germany, the survey was designed to “establish a basis for evaluating the importance and potentialities of air power as an instrument of military strategy.” The survey interviewed more than 700 Japanese officials, recovered many documents, looked at the bombs’ effects on Japanese strategy and surrender, and recorded the health and morale of citizens. Its report, published a year later, concluded with these words:
“No more forceful arguments for peace and for the international machinery of peace than the sight of the devastation of Hiroshima and Nagasaki have ever been devised. As the developer and exploiter of this ominous weapon, our nation has a responsibility, which no American should shirk, to lead in establishing and implementing the international guarantees and controls which will prevent its future use.”
In atomic history, Nagasaki and Hiroshima are the theoretical made real. Though reconstructed, what remains in those cities to shock us to action are the bombs still ticking in 106,825 human beings.