A piece in today's Guardian reveals that TEPCO, the utility responsible for the Fukushima Dai-Ichi reactors, did not until very recently have enough dosimeters for all of the employees who are working to stop an even worse catastrophe at the plant. Normally, dosimeters would be worn at all times in order to measure cumulative exposure to radiation; without them, worker exposure can only be estimated.
It's no wonder, then, that the mother of one of the workers told media that her son and his colleagues are "have accepted they will all probably die from radiation sickness in the short term or cancer in the long-term."