88Furthermore, as the Federal Republic of Germany and ClientEarth both rightly point out, there are no validated methods for all questions relating to the endocrine properties of chemical substances. Studies which are compliant with validated methods are not necessarily the most relevant, inasmuch as they do not all explore the most sensitive parameters for the identification of endocrine properties. However, as the French Republic also observes in that connection, exploratory studies are regularly conducted with the specific aim of verifying a particular scientific hypothesis, with the result that they serve, in complementarity with standard studies, to identify such properties. Consequently, an approach which, as a general rule, excludes the use of non-standard or exploratory studies would make it impossible to identify substances which pose a risk to the environment. The precautionary principle, on which the provisions of Regulation No 1907/2006 are based pursuant to Article 1(3) thereof, means that, where there is uncertainty as to the existence or extent of risks to human health, protective measures may be taken without having to wait until the reality and seriousness of those risks become fully apparent (see, to that effect, judgment of 1 October 2019, Blaise and Others, C‑616/17, EU:C:2019:800, paragraph 43).