Nazi U-boats, again.

Detroit Free Press: Nazi sub with toxic cargo pains Norway
Oslo - More than 60 years after being torpedoed by the British navy, a Nazi submarine built to threaten Allied ships continues to spread fear off the coast of Norway.

The rusting wreckage of the U-864, sunk during a desperate mission to supply Japan with advanced weapons technology, now poses a major environmental threat because of its poisonous cargo: 70 tons of mercury.

Residents on the tiny island of Fedje, located in the North Sea, want the sub removed. But authorities fear a salvage operation could result in a catastrophic spill. They suggest entombing the wreck with rocks, concrete and sand.

"Local people are very concerned," Fedje Mayor Erling Walderhaug said Wednesday. "They wanted it taken away so the danger would be gone for good."

The U-864 tried to skirt Allied navy patrols to bring jet engine parts, missile guidance systems and mercury for weapons production to Germany's ally, Japan. British experts discovered the mission by breaking a German code.

The British submarine HMS Venturer stalked the U-864 for three hours before sinking it on Feb. 9, 1945, about 2 1/2 miles off Fedje.

The U-864 was only 14 months old when it sank with a crew of 73 in 500 feet of water.

The wreck lay undisturbed for 58 years until Norway's Royal Navy discovered it in March 2003. Oslo's newspaper Dagbladet has called it "Hitler's secret poison bomb."

The mercury containers are rusting, and some are leaking.

Studies showed elevated mercury levels in the silt around the wreck, but so far only fish that live inside have been contaminated, according to the Norwegian Food Protection Authority. Fishing is not allowed in the waters nearby.

After spending three years and about $6.5 million researching the problem, the Norwegian Coastal Administration recommended encasing the submarine with sand to prevent the spread of mercury. The method, it said in a report released Tuesday, had worked 30 times worldwide and was less risky than attempting to lift the 2,400-ton sub.

"Encasing and covering are seen as permanent environmental measures," said Gunnar Gjellan, who leads the government's U-864 project. "The coastal administration recommends that the parts of the wreck be covered with a type of sand as an absorption material and an armoring layer on top to prevent corrosion."

The Ministry of Fisheries and Coastal Affairs said it will review the report before making a final decision.

When released into the ocean, metallic mercury, the silver fluid once used in thermometers, can become more dangerous organic mercury. Through fish, it can be passed on to humans in food. Mercury poisoning can be fatal.

The Norwegian environmental group Bellona has asked that the sub be removed, but Bellona's Marius Dalen said the group would now review the report.