United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)


In 1955 the General Assembly of the United Nations established a Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in response to widespread concerns regarding the effects of radiation on human health and the environment. At that time, nuclear weapons were being tested in the atmosphere, and radioactive debris was dispersing throughout the environment, reaching the human body trough intake of air, water and foods.

The Committee was requested to collect, assemble and evaluate information on the levels of ionizing radiation and radionuclides from all sources, natural and produced by man, and to study their possible effects on man and the environment. Treaties now ban tests of weapons in the atmosphere, but many other exposures to radiation occur from other sources and practices. Nuclear reactors are used in many countries to produce electric energy, and medical x-ray examination and procedures are very common throughout the world. One of the most significant sources of exposure is natural radiation that has always existed on earth and to which everyone is exposed. Natural radiation includes cosmic rays that enter the atmosphere from outer space, and potassium, uranium, radium, radon and other radionuclides in soil, water, foods and the human body.

The Committee is comprised of scientists from 27 member states . The UNSCEAR Secretariat gives the Committee the necessary assistance in carrying out its work and it consults with scientists throughout the world in establishing databases of exposure and information on the effects of radiation.

Moreover, the Committee produces the UNSCEAR Reports, which are detailed reports to the General Assembly but are also available to the scientific world. The reports review exposures from natural radiation sources, from nuclear power production and nuclear tests, exposure from medical radiation diagnosis and treatment, and from occupational exposure to radiation. They include also detailed studies on cancer induced by radiation, on the mechanism of the development of cancer and the body’s repair systems against it, further on the risks of hereditary diseases induced by exposure to radiation, and on the combined effects of radiation and other agents.