No other Japanese ship was exposed to health-damaging radiation from the 1954 U.S. hydrogen bomb tests in the Pacific Ocean aside from the Fukuryu Maru No. 5, which was contaminated by fallout from one of the tests at Bikini Atoll, according to a recently released health ministry study.
"We were not able to confirm that the exposures (of other vessels) were around the levels that would have had an impact on their health," a health ministry team said in a report last week, adding that the maximum estimated external exposure was far below the international threshold of 100 millisieverts at which an increased risk of cancer is expected.
The study began after the health ministry disclosed an abundance of records in September 2014 that were related to radiation checks conducted on ships that were in the vicinity of Bikini Atoll in the Marshall Islands when the United States conducted its hydrogen bomb tests there in 1954.