The progress of scientific knowledge is decisive for environmental, technology, and food law. The approval of products and active substances is often dependent on substance lists in chemicals law according to the REACH Regulation. The classification of substances inherent in the approval procedures is less a matter of fundamental political issues than of rather technical regulatory details – an assessment, which is to be evidence-based on scientific grounds. Risk assessment is primarily a matter of information management. Different actors need to interact to deal with (often fundamental) knowledge problems, and the interaction needs to be organized. The adaptation of substance lists has therefore been consistently delegated to the Commission by way of tertiary legislation in accordance with Article 291(2) TFEU. Despite the central importance of scientific opinions of regulatory committees for European legislation, there is a lack of coherent standards as to which rationality requirements science-based opinions of regulatory committees must observe if they are to be made the subject of legal regulation. The following article would like to use the example of the authorization of biocidal active substances to explain which criteria can be derived from case law and must be observed by regulatory committees.