In what is seen as a major embarrassment for the Kremlin, which has repeatedly promised to tighten safety checks after a number of marine accidents in recent years, an accident occurred on the Nerpa, an Akula II-class attack submarine, due to a gas leak that killed 20 people .
According to the experts, the fatalities aboard the submarine in the Sea of Japan, were the result of Freon gas spewing into the craft after a malfunction in its fire extinguishing system.