A United Nations panel has said that the radiation doses that the workers were exposed to in the initial phase of the Fukushima disaster may have been underestimated by 20 percent.
The U.N. Scientific Committee on the Effects of Atomic Radiation claimed that the tests used by the Japanese government and Tokyo Electric Power Co. (Tepco) had failed to take into account some types of radiation released by the three meltdowns at the Fukushima nuclear plant in March 2011, the Japan Times reports.
According to the report, there was a significant delay in testing the workers for radioactive iodine absorbed by their thyroid glands, and no account was taken of the potential contribution from intakes of shorter-lived isotopes of iodine, in particular iodine 133.
The report added that increased exposure to such form of iodine could lead to risk of cancer and thyroid disorders.
More workers will be eligible for free health checks, if the estimates of the U.N. committee proved to be accurate, the report added.
Tepco said about 2,000 workers, whose thyroids got doses of 100 millisieverts or more, had already qualified for cervical ultrasound inspection.