What They Learned about Radiation After the Bomb

Within six weeks after the bombing of Hiroshima and Nagasaki, three US and two Japanese teams studied the impact of radiation. The Japanese wanted to know the medical effects on survivors. The American’s wanted to know how and why people died from the blast. The Americans gathered information for a few months and left. Later, President Harry Truman approved a broader research effort. What they learned about radiation after the atom bomb blasts and what we continue to learn affects all of us today.

The yellow and black symbol for radiation danger.

The ABCC and the RERF

The National Research Council formed and funded The Atomic Bomb Casualty Commission (ABCC) to study the medical and biological effects of radiation after the A-bomb. They hoped to produce useful data for peacetime uses of atomic energy.

By 1950 the ABCC employed 143 allied and 920 Japanese personnel in Hiroshima and Nagasaki.

Unfortunately, the ABCC did not help the Japanese they studied. Signs and magazines were in English. Linoleum floors caused pregnant Japanese women wearing traditional wooden clogs to slip and fall. They didn’t offer or give medical treatments. And they offered little or no compensation for lost work to their study participant.

Over time, the hibakusha (atom bomb survivors) lost faith in the ABCC. The Atomic Energy Commission planned to withdraw their support. An appeal by an American geneticist gained the organization time and funds. But it wasn’t enough.

In April 1975, they established a new binational organization run by both the United States and Japan. And the ABCC became the Radiation Effects Research Foundation (RERF). 

The Participants

A 1950 census had helped identify 280,000 hibakusha all over Japan.

The ABCC recruited about 75,000 hibakusha who still lived in Hiroshima or Nagasaki. The participants included men and women of all ages. 

Later, the ABCC recruited an additional 20,000 to 25,000 participants.

The organization intended to follow these people for decades.

Calculating Exposure

Scientists put an enormous effort into estimating each person’s exposure level. Select survivors gave detailed information about where they were when the bomb hit. They collected copper from temple roofs at various distances from the hypocenter. Using mass spectrometry, they measured an isotope to help them estimate the amount of radiation. In 1957 and 1958, Oak Ridge National Laboratory built typical Japanese houses at the Nevada Test Site. After atomic bomb tests, they measured radiation inside and out of the buildings.

They interviewed 28,000 survivors in the 1960s. Information gathered included the survivor’s exact position, standing, sitting, direction faced, exact location within the building, and the building’s construction materials. 

Researchers used the information to calculate the dosage of radiation each survivor received. They refined the information again in the 1980s. This time they identified the radiation dosage at individual organ levels.

Possible Birth Defects

The possible effect of radiation on survivor’s children was one of the ABCC’s immediate concerns. Babies already conceived in August had small head sizes at birth. And studies done on fruit flies suggested that irradiation of adults caused heritable genetic changes and defects in offspring.

The ABCC enrolled more than 60,000 expectant mothers into their research program. (See Science Magazine’s site for details gathered during the study.) Births between 1948 and 1952 showed no correlation between parental exposure and birth defects, birth weights, or stillbirths. Unexpectedly they learned that the sex of the baby appeared to be affected by the gender of the irradiated parent. If the mother was a survivor, the likelihood of her having a daughter increased. Irradiation of the father appeared to increase the number of baby boys.

What They Learned About Radiation

image of an atom

According to Science Magazine, the ABCC/ RERF learned a lot about radiation from the atom bomb survivors. Below are some of the lessons listed by that magazine.

The younger an individual was at the time of the bombings, the greater their risk of developing cancer. The higher the dose of radiation, the higher the percentage of cancer deaths. But the risk decreased over a survivor’s lifetime.

Women were at higher risk of developing radiation-associated cancer. They believe that was largely because of additional cases of breast cancer.

Women exposed to bomb radiation at the age of her first menstruation had a higher risk of developing breast or uterine cancer later in life than those exposed before or after puberty.

Radiation most increased the risk of leukemia among survivors. Especially among those whose exposure came from near the hypocenter.

It also increased the risk of cancer of the stomach, lung, liver, and breast. Exposure also heightened the risk of heart failure and stroke, asthma, bronchitis, and gastrointestinal conditions.

How We Use What They Learned

Medical personnel, astronauts, and radiation researchers, among others, wear dosimeters. These little badges register how much radiation exposure the wearer receives. They base the recommended limits for these workers on the ABCC/RERF organization’s research.

The shielded rooms and aprons for X-rays and chemotherapy are also thanks in part to the atom bomb radiation research.

They also learned how radiation damages human cells. Read RERF’s explanation.

Have We Really Learned?

image of four hands with different skin colors clasping each other's wrists

Radiation is useful in medicine and in dating ancient objects. But did we learn our lesson about radiation as a weapon?

Time has passed. Almost 70% of the participants from Hiroshima and Nagasaki have died. The rest are in their 80s and 90s. The RERF will follow each of them until the last one dies. But the organization will continue to research the biological and medical effects of radiation for years beyond that time.

But even in Japan, people are forgetting. Once there are no more A-bomb survivors, will there be no more memories of the horror of the atom bombs dropped on Hiroshima and Nagasaki? Will what they learned about radiation after the A-bomb be enough to keep us all from dropping another bomb, a bigger bomb, on another city? Let us pray for a lasting peace. More than that, we must work to attain peace. A peace that never fears a bomb of any kind.

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