In Japan, the lifetime cancer risk level of 10^-5 is used to set the ambient air quality standard for benzene, which is a well-established cause of cancer in humans. This study assessed the “acceptable” risk level for the Japanese public aged 20–59 years regarding atmospheric carcinogen(s). Results of face-to-face questionnaire surveys conducted in 2014 indicated that more than half the respondents selected annual cancer risk level of “one in one million” or over as “acceptable”. Five percent of respondents demanded “zero-risk”, and twenty percent did not answer their “acceptable risk level” for atmospheric carcinogen(s). Moreover, the results of investigations conducted from 1999 through 2014 suggest that the acceptable risk levels for carcinogenic substances in the air have tended to increase over time.

Ensuring food safety is one of very important regulatory affairs. The Agreement of Sanitary and Phytosanitary Measures (SPS Agreement) of the World Trade Organization requires that measures related to food safety shall be based on estimated risk and scientific principles. The Codex Alimentarius Commission, the international standard setting body in the food safety area, also emphasized the importance of science and risk analysis. To support all of these activities, regulatory science serves as a good basis and is essential for making any regulatory decisions.

National policy has played a big role in improvement of environment and promotion of water supply systems, while the emphasis has been historically changed according to the social demands. To improve water supply systems, the government determines policies mainly based on scientific risk assessment, taking actual situation into account. For example, the water quality standard is determined based on the independent scientific risk assessment by the Food Safety Commission of Japan, and also based on risk management while considering existence, treatability, monitoring methods of possible contaminants. In the policy assessment, implementation of scientific risk assessment and consideration of the feasibility in risk management are important. Risk-based and other kinds of assessment methods are introduced to improve water supply and environmental conditions in administrative framework.

In this paper I will introduce the discussion on environmental risk in environmental law and policy and seize an opportunity to discuss the relation or consistency between regulatory science and environmental law. I will explain the precautionary principle and the theories on the extent of environmental risk reduction. I will also discuss the dichotomy of danger (Gefahr) and risk (Risiko).

How science should build effective and meaningful relationship with various policy making agencies, especially environmental fields, whose policy making are currently requested to be risk-based, and evidence-based way of making decisions? We begin discussion with categorization of science, risk governance, then science and regulatory policies to draw overview of science-policy interactions.