Scientific justifications for the political decision-making on environmental remediation carried out after the Fukushima nuclear accident.

The Japanese government decided to implement environmental remediation after the Fukushima Daiichi Nuclear Power Plant (termed "1F" in Japan) accident on 11th March 2011. As the initial additional annual dose target was set to be 1 mSv or less as a long-term goal, we examined the decision-making process undertaken by the then leaders, particularly the Minister of the Ministry of the Environment (MOE) who was responsible for the final decision. We found that technically based assessment of dose targets, health effects and risk-based approaches justified by scientific experts were not communicated to the then Minister and officials of the MOE before the remediation strategy was decided.