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
Period 6 element spectroscopy. The first small-scale applications for caesium have been as a "getter" in vacuum tubes and in photoelectric cells. In 1967, a specific frequency from the emission spectrum of caesium-133 was chosen to be used in the definition of the second by the International System of Units. Since then, caesium has been widely used in atomic clocks. Since the 1990s, the largest application of the element has been as caesium formate for drilling fluids. It has a range of applications in the production of electricity, in electronics, and in chemistry. The radioactive isotope caesium-137 has a half-life of about 30