The hazard function model employed internationally in radiological risk assessment for deterministic (threshold-type) biological effects of moderate and high doses of ionizing radiation is used to distinguish three levels of risk for Fukushima recovery workers: life-threatening damage unlikely (RADHAZ

The hazard function model employed internationally in radiological risk assessment for deterministic (threshold-type) biological effects of moderate and high doses of ionizing radiation is used to distinguish three levels of risk for Fukushima recovery workers: life-threatening damage unlikely (RADHAZ low), possible (RADHAZ moderate), and likely (RADHAZ high). Based on hypothetical exposures considered, life-threatening damage could reach the possible or likely range if the worker is exposed to a very large gamma spike during a work shift, say owing to a hydrogen explosion. Projected long-term increase in cancer risk from low-dose exposures of down-wind populations is purely hypothetical, since it is based on the discredited linear no-threshold (LNT) hypothesis. Such projections can lead to radiation phobia, with avoidable casualties. A radiological emergency situation currently exists at the Fukushima Dai-ichi (No. 1) nuclear power station (NPS) in Japan as a result of the Mar 11, 2011, magnitude 9.0 earthquake, which triggered a massive tsunami that killed thousands of Japanese citizens. Thousands are also still unaccounted for. The Fukushima Dai-ichi NPS is operated by the Tokyo Electric Power Company (TEPCO) and is located on the eastern coast of the main Japanese island of Honshu about 225 km north of Tokyo. The facility consists of six boiling water reactors, three (units 1 to 3) of which were operating when the earthquake occurred. The large tsunami caused by the earthquake overwhelmed the site’s sea defenses and disabled the heat exchangers and also the diesel generators, so that the site fuel-rod cooling services were then dependent on back-up batteries, which could only supply limited power for a short period. The radiological emergency arose because of the overheating of reactor fuel rods, due to a loss of electrical power for the cooling system. The Cs released from the damaged rods poses a risk to the emergency workers since its gamma emission can penetrate the body and seriously damage the radiosensitive bone marrow. Serious damage to the bone marrow can lead to radiation deterministic (threshold-type) effects that include loss of life.The workers wear protective garments and respirators to prevent inhalation intake of airborne radioactive material; thus, the focus here is on exposure to the external gamma rays that penetrate the body and protective garments. The Fukushima Disaster