Since the crisis at the Fukushima No. 1 nuclear plant began, 17 workers have suffered radiation of more than 100 millisieverts, the maximum annual exposure for nuclear plant workers until the level was raised amid the emergency.
The employees were engaged in critical work to lift the stricken six-reactor plant out of disaster amid high risks of exposure to radiation.
Tokyo Electric Power Co., the plant operator and the nation's biggest utility, says it is "up to each individual to decide whether to continue" working at the plant.