TOKYO—A prominent Japanese radiation safety specialist has resigned  his governmental advisory post in protest over what he calls "inexcusable" standards for school children in Fukushima Prefecture. The Yomiuri Online news web site reported in Japanese this evening that Toshiso Kosako, a radiation safety expert at the University of Tokyo, feels the standards are too lenient and that his advice has been ignored.
On 19 April, the ministry of education announced  a "provisional idea" for schoolyards contaminated by radiation emanating from the ravaged Fukushima Daiichi Nuclear Power Plant. The ministry cited a recommendation by the International Commission on Radiological Protection (ICRP), based in Ottawa, Canada, that sets an acceptable level of between 1 and 20 millisieverts (mSv) per year for individuals. In its Application of the Commission's Recommendations to the Protection of People Living in Long-term Contaminated Areas After a Nuclear Accident or a Radiation Emergency , ICRP recommendation reads:
The reference level for the optimization of protection of people living in contaminated areas should be selected in the lower part of the 1-20 mSv/year band.
Japan's education ministry figured that children could spend 8 hours a day in a schoolyard with as much as 3.8 microsieverts per hour of radiation and then 16 hours a day inside a building with 1.52 microsieverts per hour and stay within a 20 mSv per year limit. Some 800 groups and 34,000 individuals have signed a petition  demanding the withdrawal of the education ministry's 20 mSv per year standard, according to a coalition of citizens' organizations that will present the petition to the government on 2 May.
"Setting this (radiation exposure) number for elementary schools is inexcusable," says Kosako, according to Yomiuri Online. His resignation is expected to put additional pressure on the government to rethink its decision.