Two weeks after the attack on Pearl Harbor, a Japanese submarine shot a torpedo at an American oil tanker just off the California coast, sinking the ship and sending three million gallons (11.36 million litres) of crude to the ocean bottom.

All 38 people on board were rescued in what remains an overlooked chapter of World War II - it was one of several attacks by Japanese and German forces on the U.S. mainland during the war.

The SS Montebello has sat mostly intact 900 feet below the surface with the oil remarkably still on board after seven decades.

A mission to see how much of the oil remains in the hold of the 440-foot ship launches this week to help officials determine how to prevent the crude from leaking and marring the celebrated central California coastline.

A catastrophic release, such as an earthquake, could crack the hull of the wreck and send the crude spewing into the ocean....