A false alarm was responsible for setting off the emission of deadly fire-extinguishing gases on a new Russian nuclear-powered submarine in the Sea of Japan, killing 20 people and injuring 21 late Saturday, Russian navy officials said.
All but three of the dead were civilian specialists and experts on board the Shark-class submarine Nerpa for the performance test trial, according to the federal prosecutors office.
The ship's nuclear reactor was not affected in the accident, and the submarine returned safely to port on its own, said Russian navy spokesman Igor Dygalo. The reactor was operating properly, and the radiation levels were normal, Dygalo told the Russian news agency Interfax on Sunday.
Dygalo said that, of 208 people on board, 91 were crew members and the rest were civilian specialists and experts overseeing the testing of the submarine.
Analysts said the large presence of civilians was probably a crucial factor in the high casualty count. The regular crew would have been far better prepared for the emergency situation when the gas-emission siren rang, said Igor Kurdin, a former Russian nuclear missile submarine commander and head of the St. Petersburg Submariners Club.
"Even if you are the president of the country present on a submarine," Kurdin said, "you can't rely on your security detail to save your life in a fire, because you need to be able to save your own life by using the rescue equipment properly and quickly."
Kurdin said he believed Freon-112 was the gas emitted in two compartments of the submarine when a fire alarm went off.
Such releases are normally preceded by a specific light and sound signal, after which all on board are supposed to put on gas masks, which would give them 30 minutes to leave the affected compartments or allow them to survive until the area was adequately ventilated.
"The civilian experts on board may well be very good experts in their own technical sphere, but I am sure they were not prepared for a life-and-death survival challenge," Kurdin said.
Andrei Frolov, a researcher with the Center for Analysis of Strategies and Technologies, a Moscow-based think tank, laid some of the blame on the automatic fire-sensing system of the submarine.
"The Amur Shipbuilding Plant in Komsomolsk-on-Amur was testing this new submarine, the first one it produced in 13 years," Frolov said. "Standing virtually idle for more than a decade couldn't help but affect the expertise and skills of the shipbuilders, which must have caused this technical fault.
"I am sure many people were not prepared for what happened," Frolov said. "The accident happened at around 8:30 p.m., and some of the crew could even be sleeping already.
"I am sure the panic ensued, when the doors of the compartments were automatically sealed and the gas was emitted, and for the civilian specialists that must have been too much of a shock to handle it properly," he said.
The civilians on board included specialists from St. Petersburg, where the submarine was designed; from Nizhny Novgorod, where the nuclear reactor was designed; and from Komsomolsk-on-Amur, where the ship was built, Frolov said.
The accident was the worst in a Russian submarine since 118 crew members died when the Kursk sank in the Barents Sea in August 2000 as a result of a torpedo explosion on board.