Radiation poisoning happens when you’re exposed to extremely high radiation levels, like those caused by a nuclear explosion. Early symptoms include nausea and vomiting. Later, it causes organ damage.

Share on Pinterest
Stringer/Anadolu Agency via Getty Images

Radiation poisoning is an extremely rare condition that develops when you’re exposed to very high doses of radiation.

Radiation is energy that travels through space at the speed of light. If you come in contact with it, it can damage the DNA in your cells.

Radiation poisoning only occurs when you’re exposed to extremely high amounts of radiation in a short period of time, such as after a nuclear explosion or when directly handling radioactive materials.

The amount of radiation you’re exposed to during X-rays, cancer treatments, and other medical procedures isn’t nearly high enough to cause radiation poisoning.

Keep reading to learn everything you need to know about radiation poisoning, including its symptoms and how to prevent it.

Radiation poisoning is a term commonly used to refer to acute radiation syndrome, the sickness that occurs after you’re exposed to toxic levels of radiation.

The National Council on Radiation Protection and Measurements defines acute radiation syndrome as a broad term describing the signs and symptoms of severe damage to your organ systems after significant radiation exposure.

Radiation poisoning becomes more likely and more severe at higher radiation doses.

Scientists measure the amount of radiation absorbed by a person with two units called Gray (Gy) and rads. A radiation dose of more than 0.7 Gy, or 70 rads, can cause radiation poisoning.

Mild symptoms of radiation poisoning can start at absorption rates as low as 0.3 Gy, or 30 rads. But, relatively speaking, that’s a very high level of exposure. For reference, 0.75 Gy is roughly equivalent to receiving 18,000 chest X-rays at the same time.

Overall, radiation poisoning doesn’t happen unless:

  • The radiation reaches your internal organs.
  • A large amount of your body is exposed.
  • The dose is delivered in a short period, usually within minutes.

Radiation poisoning develops in four stages:

  • Prodromal stage: Symptoms such as vomiting, nausea, or diarrhea can appear within minutes to days after exposure.
  • Latent stage: Your symptoms subside during the latent phase, and you generally look and feel healthy for hours to weeks.
  • Manifest illness stage: Your symptoms develop again in the manifest illness stage. The symptoms depend on which of your organ systems is damaged.
  • Recovery or death: Your recovery process can last several weeks to up to 2 years. Most people die if they don’t recover within several months.

Early symptoms

Symptoms of radiation poisoning often develop shortly after exposure and can include:

Radiation poisoning syndromes

There are three classic syndromes linked to radiation poisoning. A syndrome is a group of signs and symptoms that occur together.

The three syndromes that appear during the manifest illness stage include:

  • Bone marrow syndrome: Bone marrow syndrome is characterized by the destruction of cells in your bone marrow. It usually occurs after exposure to 0.7 to 10 Gy, but mild symptoms can start at 0.3 Gy.
  • Gastrointestinal (GI) syndrome: GI syndrome usually occurs at doses of more than 10 Gy, but some symptoms might appear at 6 Gy. It’s characterized by the destruction of your GI tract, dehydration, and electrolyte imbalances. Survival from this syndrome is unlikely.
  • Cardiovascular and central nervous syndrome: This syndrome usually occurs at doses of more than 50 Gy but can sometimes occur at doses as low as 20 Gy. Death occurs within 3 days, often due to the destruction of your circulatory system.

Radiation poisoning is rare. It usually occurs after:

  • extreme events like nuclear explosions
  • directly handling highly radioactive materials
  • consuming nuclear-contaminated food or water

The Chernobyl explosion in the former Soviet Union in 1986 and the Hiroshima and Nagasaki bombings in 1945 are two examples of events that exposed humans to lethal amounts of radiation.

Your chances of developing radiation poisoning are higher the closer you are to a nuclear explosion.

X-rays and medical equipment don’t expose you to enough radiation to cause radiation poisoning. But repeated exposure may slightly increase your risk of cancer over your lifetime.

Decontaminating as soon as possible after a nuclear event can help you reduce your radiation exposure.

Taking off your clothing and washing your body with soapy water can remove most radioactive contamination. Removing contaminated clothing alone can reduce your exposure by 80%.

In the event of a terrorist attack, the Centers for Disease Control and Prevention (CDC) recommends:

  • undressing at your doorway or garage if possible before entering your home
  • avoiding unnecessary hand-to-face contact and avoiding chewing gum or smoking until after decontamination
  • showering with warm water and soap
  • gently blowing your nose, wiping your eyelids, and cleaning out your ears
  • changing into clean clothing
  • rinsing out your tub or shower
  • tuning into media for instructions from public health officials in your area

What to do in case of a radiation emergency

If you’re in a radiation emergency, you can reduce your risks by taking the following steps:

  • Get inside a building and close and lock the windows and doors.
  • Go to the middle of the building or to the basement, away from doors and windows.
  • Bring pets inside if you’re at home.
  • Stay inside with the windows and doors closed.
  • Shower or wipe exposed parts of your body with a damp cloth.
  • Drink bottled water and eat food that’s in sealed containers.
  • Listen for news from emergency channels to understand what’s happening.

Exposure to high levels of radiation can raise your future risk of developing long-term problems like cancer or cardiovascular disease.

Some research has shown that a type of blood cancer called leukemia can form within 2 years of radiation exposure, but cancerous tumors usually don’t occur until at least 10 years after exposure.

A group of 94,000 Hiroshima and Nagasaki survivors was studied for many years to understand the effects of radiation exposure. Of all the survivors with leukemia among that group, the leukemia was attributed to radiation exposure in about one-third of them.

The rates of thyroid cancer in children and adolescents living around the Chernobyl explosion was about 100 times higher than would have been expected.

The risk of developing cancer increases with increasing radiation exposure. Doses of 0.005 to 0.1 Gy are thought to increase cancer risk by 2%. But your risk increases by more than 60% for doses of more than 2 Gy.

Here are some frequently asked questions people have about the effects of radiation poisoning.

Does iodine treat radiation poisoning?

Iodine doesn’t help treat radiation poisoning, but it may help prevent your thyroid gland from absorbing radioactive iodine, which can increase your risk of thyroid cancer. More than 6,000 children developed thyroid cancer after the Chernobyl explosion.

It’s recommended that all children and females exposed to high levels of radiation be offered potassium iodine supplements.

Can cancer treatments cause radiation poisoning?

The amount of radiation used in cancer treatments isn’t enough to cause radiation poisoning. But it can still cause side effects. For example, radiation to your brain can cause cognitive effects that may not show up for more than 6 months after treatment.

Can you survive radiation poisoning?

It’s possible to survive radiation poisoning. Your chances of survival decrease with increasing doses of radiation.

Did people die of radiation poisoning in Chernobyl?

According to the World Nuclear Association, two Chernobyl plant workers died directly from the explosion and 28 other people died within a few weeks from exposure to very high amounts of radiation.

Radiation poisoning is caused by high doses of radiation such as those from nuclear explosions or from direct handling or consumption of radioactive material.

Early symptoms of radiation poisoning such as nausea, vomiting, or headaches can start within minutes to days.

Recovery from radiation poisoning can take from several weeks to 2 years.

The chances of surviving radiation poisoning decrease with increasing doses of radiation.