The Ministerial ordinance on exemption of the Ordinance on Prevention of Ionizing Radiation Hazards in response to the situation resulting from the Tohoku-Pacific Ocean Earthquake in 2011 raised the upper radiation exposure dose limit during emergency works from 100mSv to 250mSv only for the particularly unavoidable emergency case at the Fukushima Daiichi Nuclear Power Plant and the detailed provisions were specified in item No.2 in the Note of the Labour Standards Bureau Notification No.0315-7 (15 March 2011) in accordance with Article 1 “Basic Principles” of the Ordinance on Prevention of Ionizing Radiation Hazards. Guidance about the radiation exposure dose during later radiation works other than emergency works for the workers who had been engaged in emergency works at the Fukushima Daiichi Nuclear Power Plant is shown below and careful attention should be paid to it.