Helen ApSimon founding member and Chairman of the European Association for the Science of Air Pollution. ApSimon is well known for her research into the transport of radioactivity from the Chernobyl disaster. In the immediate aftermath, Russia issued a media blackout and ApSimon was one of few European scientists to detect rising radiation levels. She modelled the nuclear fallout, calculating Chernobyl released 15 - 20 megacuries of Iodine-131 and 1 - 2 megacuries of caesium-137. During the first few weeks after the disaster, ApSimon calculated the radioactive plum covered Scandinavia and the North coast of Europe. She travelled to Hungary, Poland, Czechoslovakia
Caesium-137 junkyards, and the glowing caesium salt sold to curious, unadvised buyers. This led to four confirmed deaths and several serious injuries from radiation contamination. Caesium gamma-ray sources that have been encased in metallic housings can be mixed in with scrap metal on its way to smelters, resulting in production of steel contaminated with radioactivity. The Kramatorsk radiological accident happened in 1989 when a small capsule containing highly radioactive caesium-137 was found inside the concrete wall of an apartment building in Kramatorsk, Ukrainian SSR. It is believed that the capsule, originally a part of a measurement device, was lost in the