Emergency response technical work at Fukushima Dai-ichi nuclear power plant: occupational health challenges posed by the nuclear disaster

INTRODUCTION Fukushima Dai-ichi nuclear power plant (NPP) was heavily damaged by the tsunami that resulted from the 9.0-magnitude earthquake which occurred off the coast of eastern Japan on 11 March 2011. The loss of all alternating current (AC) electrical power, even from emergency generators, disabled cooling functions and the supply of recycled water. Hydrogen explosions destroyed two reactor buildings and there was meltdown of the reactor cores. The nuclear accident was assigned the maximum severity level of 7, which is equal to that of the Chernobyl disaster that occurred in 1986. Efforts were made to achieve stable cooling of the nuclear reactors, and the release of radioactive materials was brought under control. On 16 December 2011, the Japanese government, the Tokyo Electric Power Company (TEPCO) and technical-support companies achieved cold shutdown of all the reactors stricken by the tsunami. During this period, numerous efforts were made to protect disaster response technical workers. The aim of this paper is to describe the greatly increased risk from hazards that disaster response technical workers faced because of the Fukushima Dai-ichi NPP disaster.