Agency officials said on Wednesday that they checked the lungs of the workers 10 hours after the accident and detected 22,000 becquerels of plutonium-239 in the lungs of a worker in his 50s. They said the amount translates into up to 12 sieverts of internal exposure over 50 years, and that most of the substances will be discharged from his body.
But they did not mention the worker’s total internal exposure at that time.
The officials now say that based on the measurement, they estimate that the worker took in more than 360,000 becquerels right after the accident.
They say the figure is just an estimate and that they originally decided to disclose only the 22,000-becquerel measurement.