Radioactive contamination. Fenced-off land which has been contaminated with radioactive fall-out from the Mayak disaster in Russia. On 29 September 1957 at the Mayak nuclear fuel reprocessing plant, a tank holding 300 cubic metres of nuclear waste exploded. About 250,000 people were exposed to the 20 million curies of radiation released. This was about half as much radiation as was released from the Chernobyl disaster of 1986. Since Mayak opened, routine dumping of waste & a series of accidents have contaminated surrounding areas further. Radioactive chemicals can remain danger- ous for tens of thousands of years. Radiation causes tissue death, cancers & genetic defects.