International Nuclear Safety Group the Kyshtym disaster, which occurred at Mayak, a Nuclear fuel reprocessing plant in the Soviet Union. Since then, there have been hundreds of nuclear accidents, some considered minor while others were horrendous, with one of the worst accidents being the Chernobyl disaster of April 26, 1986. Involving a nuclear power plant at Chernobyl, now in Ukraine, a combination of nuclear volatility and the disregard of several safety procedures caused an explosion of its fourth reactor, ending in the worldwide environmental and human catastrophe. Following the Chernobyl accident, the IAEA was forced to create a new branch of their organisation to
Ryanggang explosion popular speculation that the explosion was nuclear in origin. United States Secretary of State Colin Powell said there was "no indication" that it was nuclear, and South Korea similarly said that it did not appear to be nuclear. It would be some days before the effects of a nuclear explosion would be unequivocally visible to apolitical authorities. It would not be possible to hide the nuclear nature of such an explosion for long, as the radioactive isotopes created by a nuclear explosion would be detectable to outside observers around the world. North Korea initially denied that the explosion was nuclear.