In August 2000, the Russian Oscar II-class submarine Kursk sank in the Barents Sea when a leak of high-test peroxide in the forward torpedo room led to the detonation of a torpedo warhead, which in turn triggered the explosion of around half a dozen other warheads about two minutes later. This second explosion was equivalent to about 3–7 tons of TNT[1] and was large enough to register on seismographs across Northern Europe.[2] The explosion and the flooding by high pressure seawater killed the majority of the submarine's 118 sailors.