U.S. crews flying in aid exposed to radiation

U.S. military helicopter crews tested posted for radiation exposure today after flying relief supplies into the tsunami-ravaged northeast of Japan.

Navy helicopters from the aircraft carrier USS Ronald Reagan and from Naval Air Station Atsugi located outside Tokyo flew 29 sorties Tuesday.

On their return, reports CBS News national security correspondent David Martin, crews tested positive for radiation and had to be decontaminated.

In some cases, crews were giving potassium iodine pills - no crews had to be given potassium iodine yesterday when 17 crew members returning to the Reagan tested positive.

Positive readings for radiation were also made at a U.S. Naval installation 28 miles south of Tokyo.

The readings at Navy Base Yokosuka (which is about 160 miles south of Fukushima) mean winds carrying a plume of radioactive emissions from the damaged nuclear reactors in Fukushima have shifted direction and are likely passing over the capital.

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The military is now doing sophisticated calculations to figure out how long crews, planes and helicopters can remain in the plume.

Martin also reports that a U.S. Naval amphibious group led by the Essex has changed its route - instead of operating off of Japan's east coast, the group will now go around Japan via the Inland Sea and operate off of the west coast.