Nausea, Blisters, Organ Failure, and Cancer: Why the Side Effects of Radiation Poisoning Vary So Widely

Last February, the Chernobyl power plant fell under the control of the Russian army. Disregarding cautions to avoid contaminated zones, troops dug trenches in the radioactive soil. Several weeks later, local residents witnessed soldiers afflicted with radiation sickness, displaying evident symptoms such as vomiting and sizable blisters on their skin. These actions not only harmed the soldiers themselves but also caused a significant surge in background radiation levels within the vicinity. Forty years after the explosion of the Chernobyl nuclear power plant, which rendered miles of land uninhabitable, it remains a devastating hazard to human health. The incident is a poignant reminder that nuclear accidents have lasting consequences.

Whether it is the legacy of Chernobyl, the renewed threat of nuclear war due to conflicts like the one in Ukraine, or even the ongoing cleanup effort of the Fukushima Daiichi nuclear power plant in Japan—which is slated to release treated radioactive wastewater into the sea—radiation exposure is an integral part of modern life.

However, since 1945, when the United States detonated two atomic bombs over Japan, scientists have meticulously investigated the ramifications of radiation. What they have gleaned, not only the consequences for those exposed but also for generations yet to come, may surprise you.

Radiation Poisoning and Its Side Effects

Symptoms of acute radiation syndrome include vomiting, diarrhea, headache, fever, and hair loss. The bone marrow and gastrointestinal tract are especially sensitive, and people may develop aplastic anemia, a rare blood disorder in which the marrow cannot make new blood cells, and a devastating and rapid form of leukemia. Patients die due to infection, dehydration, and electrolyte imbalance.

High-energy ionizing radiation, like the type from the atomic bombs, harms living cells by blasting electrons out of atoms. These high-energy particles break molecular bonds in important cell structures like DNA. If an ionizing radiation particle hits DNA directly, it cleaves its molecular bonds and introduces mutations in the cell’s instructions.

How do you get radiation poisoning?

In order to get acute radiation syndrome, also known as radiation poisoning or radiation sickness, a person must typically be exposed to a high level of radiation over the course of a few minutes, specifically more than 0.7 Gy—short for gray, the unit for the absorbed dose of ionizing radiation. Some could die after being exposed to as little as 1.2 Gy, according to the CDC, but typically a higher dose of 2.5 to 5 Gy is needed and results in death in 50 percent of those exposed after 60 days. A dose of 10 Gy or higher almost always results in death.

To put those numbers into perspective, victims of the Hiroshima bombing who were within a mile of the bomb’s hypocenter (the exact, mid-air spot where it exploded 590 feet above the ground) received 9.46 Gy. And the infamous mass of highly radioactive material known as the “elephant’s foot,” that was created during the Chernobyl meltdown, could expose someone to a fatal dose of 4.5 Gy within five minutes, or as much as 80 to 100 Gy in an hour.

While the body has ways of healing, the effectiveness of repair mechanisms depends on the degree of damage. “If the damage is sparse, then there is a high likelihood it gets repaired,” Kathyrn Higley, radiological health researcher and professor at Oregon State University, tells Popular Mechanics. “If many pieces of DNA get damaged, the cell may just undergo cell suicide,” she says.

According to Higley, DNA is particularly susceptible because it is condensed and packaged in the cell, and a high-energy particle passing through might break many bonds in a small space. “It just depends on what gets hit and whether the damage is fixable,” she says. Many hits to the DNA could lead to cell death and organ failure. Fewer hits might spare the cell from rapid death, but could set the stage for diseases like cancer later in life.


The “elephant’s foot” is a mass of highly radioactive materials that formed during the Chernobyl nuclear reactor meltdown.

Universal History Archive//Getty ImagesHindsight From Hiroshima and Nagasaki

Most of what is known today about the health effects of atomic radiation stems from research on the Japanese atomic bomb survivors. When the atomic bomb was dropped on Hiroshima on August 6, 1945, the blast leveled the city and destroyed every structure within a mile of ground zero. It also caused a devastating loss of life. In Hiroshima, the bomb killed 70,000 people instantly.

The atomic bomb that struck Nagasaki just a few days afterward killed another 40,000 people. Many died during the initial blast and the firestorm that ensued, but thousands more died from the effects of radiation later on. In Hiroshima alone, the death toll climbed to over 100,000 by the end of 1945 and exceeded 200,000 after five years.

In 1945, the National Academy of Sciences established the Radiation Effects Research Foundation (RERF), a joint effort by American and Japanese scientists, to follow the development of cancer and other diseases in its victims. According to Jon Samet, dean of the School of Public Health at University of Colorado and RERF Counselor, the studies were set up for two reasons: to study the health effects on survivors and whether they could be passed down to their descendants.


Kaz Suyeishi, of the American Society of Hiroshima-Nagasaki A-Bomb Survivors, is seen here describing her experience, saying the bomb’s explosion looked “like heaven” before “everything turned to hell.” Her and other survivors met in Los Angeles in 2003, to be examined by physicians and researchers from the Radiation Effects Research Foundation.

David McNew//Getty Images

The scientists systematically followed the experience of 120,000 survivors in Japan. This group, collectively named hibakusha, were stigmatized in Japan due to fears that radiation sickness was transmissible and could be passed down to children. They were deemed unsuitable to bear children and were sometimes refused housing and food.

Early on, scientists discovered survivors were likely to develop leukemia. Up to 44 percent of all leukemia deaths in atomic bomb survivors between 1950 and 1990 were caused by radiation exposure. For other types of cancers, the rate was much lower but still significant. For solid tumor cancers, like breast and thyroid, scientists found that 11 percent were due to radiation exposure.


Portaits of survivors of the 1945 atomic bombing of Hiroshima: (top L to R) Keiko Ogura, Park Nam-Joo, Sunao Tsuboi, and (bottom row L to R) Shigeaki Mori, Misako Katani, and Emiko Okada. Taken May 2016.


The risks also increased with the dose, with those receiving higher than five millisieverts having a higher chance of developing cancer. (A millisievert is about the amount of radiation a typical American receives each year.) Age and sex also mattered. Younger people and women were more likely to get cancer. And other health related problems like cardiovascular disease and cataracts also developed in a higher incidence in bomb survivors.

Sieverts vs Grays: What’s the Difference?

The gray is the unit that quantifies the physical amount of radiation that is absorbed by mass, or simply, the “absorbed dose” of radiation. The sievert, by comparison, is the unit that quantifies the biological effect that a dose of radiation has on the body. Sieverts are used to measure both the “equivalent dose” for individual organs and the “effective dose” for the entire body.

The Children of Chernobyl

Can damage caused by radiation be passed down to future generations? If a particle of radiation were to travel into the eggs or sperm and cause mutations, would those mutations travel into future generations? And what would the effects be?

“Early on, the assumption was you’re gonna have all sorts of genetic hereditary effects that we need to protect people from,” said Higley. “But, one of the things to come out of this research is that it is not as big of an issue as we thought.”

Today, tens of thousands of children of bomb survivors are still being monitored, and so far, no clear transgenerational effects have been discovered. Researchers have looked to other irradiated populations also. In 2021, researchers from the National Cancer Institute published a landmark study that followed the children of the clean-up workers or “liquidators” at the Chernobyl Nuclear Power Plant.

In 1986, a reactor at the power plant exploded and sent plumes of radioactive contamination over a wide area. The explosion exposed roughly 350,000 people to high radiation levels, and the clean-up effort endangered an additional 500,000 clean-up workers. The researchers tracked down families with parents that were either clean-up workers or evacuees. They carefully reconstructed estimates of radiation doses by checking dosimeter records in workers and measuring the uptake of radioactive iodine by the thyroid gland in evacuees.

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