This paper presents the results of a study on environmental monitoring during the transition and long-term phases following a major nuclear accident—topics addressed by the Emergency Monitoring Committee in the Society of Health Physics—and offers relevant recommendations. Given the scarcity of international case studies involving sustained monitoring during these phases, the post-Fukushima experience offers an exceptionally instructive reference. We reviewed detailed project records on environmental radiation mapping using airborne, vehicle-borne, and ground-based methods; food safety monitoring; and individual dose measurements. In particular, the Comprehensive Radiation Monitoring Plan developed after the Fukushima accident organized extensive, long-duration monitoring projects, resulting in a wealth of practical reports on both established and emerging technologies, as well as their field performance and experiences. Building on these lessons, we argue that establishing a formal yet adaptable framework for transition and long-term environmental monitoring is now imperative for future preparedness against large-scale nuclear accidents. Informed by the post-Fukushima record and expert discussions, the committee has drafted a set of recommendations outlining objectives, operational scope, and implementation logistics for transition and long-term monitoring.

Tritium is used in many fields as technology advances, so it is essential to understand how this affects the environment. However, there are many issues with current tritium analysis, especially OBT analysis. These include the situation that it is complicated and time-consuming. There is no standard sample with which to evaluate the analysis techniques, nor any standardized analytical method. This leads to a lack of data on the environmental behavior of tritium. To select the appropriate analytical method and measurement equipment, it is important to determine the concentration level and sample type. This paper therefore introduces these issues in detail.

The Japan Health Physics Society (International Correspondence Committee, Planning Committee) and the Japanese Radiation Research Society (Globalization Committee, Education and Training Committee, Radiation Risk and Protection Committee, Public Relations and Publication Committee) held a joint symposium on the draft report of the International Commission on Radiological Protection (ICRP) Task Group 91 on May 24, 2025. At this symposium, experts in radiobiology, epidemiology and radiological protection made presentations to explain the contents of the draft report, followed by a general discussion among all presenters and participants.