Hundreds of crew members have died in accidents on submarines. Some recent accidents:
Aug. 4, 2005: A Russian mini-submarine with seven sailors aboard snags on a fishing net and gets stuck on the Pacific floor about 50 miles off Russia's Kamchatka Peninsula.
Jan. 8, 2005: The submarine USS San Francisco strikes an undersea mountain in the Pacific Ocean en route to Australia, killing one sailor and injuring 97 others.
Oct. 5, 2004: An electrical fire breaks out on the Canadian submarine Chicoutimi off the coast of Ireland, and Britain's Royal Air Force dispatches a search and rescue helicopter. One crew member dies.
May 22, 2002: The U.S. Navy research submarine Dolphin catches fire and is partially flooded about 100 miles off San Diego. All 43 people aboard are rescued.
Feb. 9, 2001: The submarine USS Greeneville crashes into a Japanese fishing vessel while conducting a rapid-ascent drill off Hawaii. Nine people are killed aboard the Japanese ship.
Aug. 12, 2000: The nuclear-powered Russian submarine Kursk goes down in the Barents Sea after an explosion during a military exercise. All 118 crew members die.
April 7, 1989: The Soviet submarine Komsomolets catches fire and sinks off Norway, killing 42 of the 69 sailors aboard.
Oct. 3, 1986: A Soviet submarine catches fire and sinks 600 miles east of Bermuda. The Soviets said three sailors died.
Summer 1983: A Soviet submarine sinks in the northern Pacific, killing 90 crew members, according to U.S. intelligence officials.
April 9, 1981: The USS George Washington, a missile submarine, runs into the Japanese freighter Nisso Maru, sinking the ship off the southern tip of Japan and killing two Japanese crewmen.
Aug. 23, 1980: A Soviet Echo-1-class submarine catches fire and radios for help off Japan. Japanese officials later report that nine crewmen died.
April 11, 1970: A Soviet November-class submarine sinks in the Bay of Biscay off Spain, killing 52 people.
May 21, 1968: The USS Scorpion, an attack submarine, is lost with 99 men aboard off the Azores in the Atlantic.
April 10, 1963: The USS Thresher is lost 220 miles off the New England coast with all 129 men aboard.