6 Juin 2016
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.
With the disclosure, the ministry also retracted its earlier, long-held position that the radiation testing records no longer existed.
Supporters of the former Fukuryu Maru fishermen said that the health ministry’s new study wasn’t thorough enough.
“The government study is only checking radiation exposures from the first of the six tests held,” said Masatoshi Yamashita, 71, an executive at a civic group who’s been researching the Bikini Atoll case for over 30 years. “It’s not enough.”
While the story of the tuna trawler also known as the Lucky Dragon is well known for the fatal H-bomb fallout that rained down on its deck following the test on March 1, 1954, details about the radiation exposure received by other ships that were in the vicinity at the time have largely been a mystery.
This is the first time that the government has come up with an estimate of the radiation received by other ships’ crews, the Health, Labor and Welfare Ministry said.
Earlier this year, a group of former crew members from those ships applied for workers’ compensation for cancer and other diseases that they say were caused by exposure to the atomic tests.
The report, however, says the health ministry team did not find clear signs that the radiation had affected the white and red blood cell counts of those who were exposed, based on blood tests and other data contained in the records disclosed in 2014.
It also reported that the maximum external exposure stood at 1.12 millisieverts, and claimed that internal exposure is likely to have been “quite small in comparison to the external exposure,” based on other exposure studies related to the Fukuryu Maru’s crew and to residents of the Marshall Islands.
All 23 members of the Fukuryu Maru began developing acute symptoms of radiation sickness shortly after the trawler was showered by fallout from the Castle Bravo H-bomb test on March 1, 1954.
One member of the fishing boat died about six months later at the age of 40.