A theory of chemicals regulation and testing

Risk management of chemicals requires information about their adverse effects such as toxicity and persistence, for example. Testing of chemicals allows for improving the information base for regulatory decision‐making on chemicals' production and use. Testing a large number of chemicals with limited time and resources forces a prioritization of chemicals. This paper proposes a decision model that provides a ranking of chemicals according to “urgency to test”. The model adopts a value‐of‐information approach describing the expected welfare gains from regulatory actions that respond to test information. We determine the value‐of‐information of tests revealing chemicals' levels of toxicity and persistence. We compare our findings to the prioritization of chemicals in the new European Chemicals Regulation “REACH”, where several tens of thousands of chemicals are to be tested in order to fill existing information gaps and to implement more effective risk management. We find that the main lines of chemicals' prioritization under REACH receive backing from our decision model. However, prioritization for testing can be further improved by accounting for testing costs and the sensitivity of regulatory action with respect to the test information.