There are many effects of ionizing radiation depending on the dose one receives. Ionizing radiation is either waves or particles that cause atoms they hit to lose their electrons, ionizing the atoms. This process can have a detrimental effect on living organisms, as ionized atoms, also known as free radicals, damage the human body on a genetic level. Depending on the dose, the effects of ionizing radiation can range from no noticeable symptoms to cancer. As ionizing radiation is a concern in many industries, different regulations and protective measures exist to protect employees.
The primary sources of ionizing radiation are cosmic rays, nuclear fusion, nuclear fission and radioactive decay. Any of these sources can produce one the three main types of ionizing radiation: alpha, beta and gamma. Alpha is the least harmful while gamma, produced in large amounts during a nuclear explosion, is the most harmful. Many safety measures are necessary to protect against gamma radiation. That is not to say though that a massive dose of alpha or beta radiation would not harm a person.
The effects of ionizing radiation begin on the cellular level. At the moment of exposure, free radicals pass through the body at the speed of light. It is in the cell nucleus, the storage area for an organism's genetic material, where the bombardment does the most damage. If a strand of DNA receives a small amount of damage, the DNA can repair itself. Add a little more damage and the cell will self-destruct to not cause further harm to the organism.
The effects of ionizing radiation become a problem when the cell becomes so damaged that its self-destruct mechanism no longer works. In animals, one cell can become the seed for a malignant cancer. Higher doses of ionizing radiation may cause several tumors to develop throughout the body. The most extreme effects occur when an animal receives a lethal dose of ionizing radiation. Rapidly dividing cells such as those found in bone marrow and the gastrointestinal lining die en mass due to their damaged DNA; death is nearly certain.
Industries whose employees are at risk for the effects of ionizing radiation generally have policies and protective measures in place to prevent exposure. For example, nuclear power plants and nuclear research labs have both lead and graphite shielding to protect engineers against radioactive materials. These facilities also have radiation detectors that can quickly notify employees if any radiation leak should occur. Most hospitals with X-ray labs have the same safeguards in place. In commercial aviation, many airlines prevent pregnant women from acting as part of a flight crew due to the increased levels of ionizing radiation present in the upper atmosphere.