Deaths due to the Chernobyl disaster and other diseases with longer time latencies following the release of radioactive debris from the disaster. A United Nations' International Atomic Energy Agency (IAEA) study estimates the final total of premature deaths associated with the disaster will be around 4000, mostly from an estimated 3% increase in cancers, which are already common causes of death in the region. Some non-governmental organizations, many with staunch positions on the spectrum of the nuclear power debate, have claimed numbers up to a million excess deaths caused by the nuclear disaster. UN and other international agencies such as the Chernobyl Forum and the World
Caesium-137 populates the ground state of barium-137, which is stable. Ba-137m has a half-life of about 153 seconds, and is responsible for all of the emissions of gamma rays in samples of caesium-137. 85.1% of metastable barium then decays to ground state by emission of gamma rays having energy 0.6617 MeV. One gram of caesium-137 has an activity of 3.215 terabecquerel (TBq). The main photon peak of Ba-137m is 662 keV. Caesium-137 has a number of practical uses. In small amounts, it is used to calibrate radiation-detection equipment. In medicine, it is used in radiation therapy. In industry, it is used