The Obsky 402, a dredge boat used for decades to collect sediments from the Tom River. The sediments in the river were contaminated and many of the crew has fallen ill. Workers on the boat knew the sediments in the river were polluted but paid no attention to it. Many inhabitants of cities surrounding the Siberian Group of Chemical Enterprises and its workers have fallen ill. The SGCE is located in the closed city of Seversk and has had over 35 accidents in four decades. The town, once called Tomsk-7, was a secret city until 1992 and did not appear on official maps. The city still remains closed to non-residents. The last major accident took place in 1993. An explosion destroyed part of a reprocessing facility and an area of 200 square kilometers was contaminated with radioactive materials, resulting in evacuations and ongoing devastation. Radioactive materials from Europe are still processed by the SGCE and additional contamination stems from deliberate dumping of highly radioactive waste in the Tom River.