The National Institute for Environmental Studies (NIES) is implementing the “Comprehensive Environmental Risk Research Program” as one of the strategic research programs in its Fifth Mid- to Long-Term Plan (FY2021–2025). This program aims to expand the scope of risk assessment to encompass all chemicals of concern that are manufactured and used, in order to comprehensively assess and manage the risks posed by chemical substances resulting from human activities, and to assess effects and risks that have been difficult to quantify by considering vulnerable populations and life histories, and by improving comprehensive measurement and mathematical models. The program also aims to develop comprehensive environmental risk indicators to contribute to the formulation and revision of chemical management measures implemented by the Ministry of the Environment and international organizations. This manuscript introduces the contents of a special session held at the 37th Annual Meeting of the Society for Risk Analysis Japan. In the session, an overview of the Comprehensive Environmental Risk Research Program was presented, followed by presentations of research on health hazard assessment, ecological hazard assessment, comprehensive measurement methods for identifying multiple and combined exposures, mathematical modeling for understanding the environmental dynamics of all chemicals of concern, and the proposal of comprehensive risk indicators. Based on these presentations, the direction of research on comprehensive environmental risk assessment for “all chemicals of concern” was discussed.

Amid the COVID-19 pandemic, regulatory frameworks for chemical management have evolved, integrating circular economy and sustainability principles. Changes in European regulations, international treaties, and other regulatory frameworks indicate the need to reassess existing approaches and identify best practices. The session, held during Society for Risk Analysis Japan Annual meeting 2024, provided an overview of recent developments, including the Global Framework on Chemicals (GFC), the Plastics Treaty, the European Green Deal, and the Chemicals Strategy for Sustainability. Discussions focused on the future of global chemical risk governance from a risk science perspective, highlighting key challenges and opportunities for establishing sustainable and effective regulatory strategies.

The selection of final disposal sites of soils generated by decontamination after the Fukushima Daiichi Nuclear Power Station accident is an urgent issue. In this study, we identified major factors related to acceptance of final disposal sites using decision tree analysis under three different questions: (1) approval of final disposal near one’s place of residence (base question), (2) acceptance of final disposal when residents’ opinions were reflected (procedural fairness question), and (3) acceptance of final disposal when sites were divided into 46 prefectures (distributive fairness question). Three thousand people aged 20 to 79 years living in 46 prefectures other than Fukushima Prefecture were randomly selected and surveyed from September to December 2022 by postal method. The analysis was conducted on 806 individuals who gave consent and had no missing survey items. The results revealed that regardless of questions, protected values were present in the first layer. In the second layer, dread risk perception, intergenerational expectations, and social benefit perception were extracted at the base question; social benefit perception and trust at the procedural fairness question; and inequity, interest, and social benefit perception at the distributive fairness question. Acceptance of final disposition is largely governed by protected values. Social benefit perception was extracted in the second layer in any questions, suggesting that discussion on social benefits is important in the selection of final disposal sites. Furthermore, enhancing trust is particularly important in selecting final disposal sites when residents’ opinions are reflected.

The issue of acceptance of site selection for geological disposal facilities for high-level radioactive waste is still an important research topic despite the existing various studies. This study focused on differences in the site selection procedure, and aimed to determine the factors influencing acceptance in terms of procedural fairness and interregional fairness. The results of a web-based hypothetical scenario experiment showed that the acceptance of geological disposal policy influences site acceptance regardless of the site selection procedure. Meanwhile, the procedural fairness of the site selection influences site acceptance in the public invitation/offer procedure, whereas the procedural fairness of the site selection, interregional equity, and expectation of national consensus influence site acceptance in the screening procedure.

The purpose of this study was to determine the extent of Bousaisi’s knowledge and anxiety about radiation and their behavioral intentions for radiation disaster mitigation. A questionnaire survey on radiation disaster prevention was administered to Bousaisi in Japan, and 666 responses were analyzed. The results showed that Bousaisi’s knowledge of radiation was not sufficient, and they expressed high anxiety in many health hazard items. From the open-ended statements regarding behavioral intentions for disaster risk reduction, Bousaisi with less knowledge about radiation and those with higher levels of radiation anxiety tended to report that they did not know what to do in the event of a disaster. These results suggest the need to educate Bousaisi on radiation disaster prevention and clarify their behavioral intentions for disaster risk reduction.