Since the 2011 triple meltdown at Fukushima No. 1, more than 53,000 cleanup and response workers have logged annual radiation exposure exceeding 5 millisieverts (mSv).
Reportedly, the number is the official threshold for qualifying leukemia as a compensable work-related illness under Japanese public insurance.
So far, at least 17 workers have been recognized with occupational radiation illnesses (including leukemia and solid cancers), resulting in at least two deaths.
Authorities expect the number of recognized workplace injury claims to rise further. The decommissioning operations are slated to continue through 2051, and Fukushima’s annual cumulative radiation levels still far outstrip any other Japanese plant.
The 15-year total is based on TEPCO’s official radiation tracking reports, analyzed by Jiji Press, covering the period from the 2011 meltdown through March of this year.
Recognized work-related illnesses
Radiation exposure for workers spiked sharply right after the 2011 meltdown. In the first two years alone, over 600 workers exceeded the normal safety limit of 50 mSv per year. However, safety measures improved quickly, and no worker has surpassed that annual limit since 2013. As a result, the average yearly dose per person dropped from a high of 21.6 mSv in 2010 to just 1.7 mSv in 2025.