Radiation sickness is caused by exposure to a large amount of radiation. This may be the result of a nuclear accident or the explosion of a nuclear weapon. Radiation sickness can be acute or chronic.

The acute form of the disease can develop quickly, within a few hours or days of exposure. A person with acute radiation sickness has usually been exposed to large amounts of radiation over a very brief period of time. This happens in the case of a nuclear plant accident or a nuclear bomb explosion.

It may take several days or weeks to develop the chronic form of the disease. A person with chronic radiation sickness has usually been exposed to lower doses over a longer period of time. This happens in the case of radioactive fallout from a nuclear explosion or accident. It may also be caused by long-term exposure to radiation in the workplace.

What is going on in the body?

When radiation penetrates the body, the effects are felt first in individual cells. With very high doses of radiation, many cells will die. Other cells will not be able to function normally. The tissues made up of these cells will then not function. Eventually the function of the body will break down. If the damage is great enough, the person will die. If the damage is less, the person may be very sick, but may recover. The larger the area of the body that is exposed, the more severe the disease will be.

What are the causes and risks of the disease?

A person can be exposed to radiation anywhere radioactive materials are used. This includes nuclear power plants and research labs. Other places include mines where the materials are removed. The detonation of any size nuclear device will release radioactive material.