The primary process established by the European Commission to address the science needed to define key REACH concepts and to help rationally implement REACH's ambitions is enshrined in a series of activities known as the REACH Implementation Projects (RIPs). These are projects that aim to define the methodology that could be used, and present the basis for guidance on the actual principles and procedures that may be (are proposed to be) followed in the development of the required documentation that ensures the safe use of chemicals. In order to develop soundly based and equitable regulation, it is necessary that science governance using established and accepted scientific principles must take a leading role. The extent to which such governance is embraced will be determined by many factors, but notably the process adopted to enable scientific discussion to take place. This article addresses the issues of science as they have impacted on the exemplification of the Exposure Scenario concept under REACH. The current RIP activities have created a non-adversarial process in which the key stakeholders are able to discuss the key REACH challenges. But the RIP activities will be finalised before REACH comes into force. A suitable mechanism should perhaps now be identified to ensure that this positive spirit of scientific discussion and collaboration can continue to benefit REACH and those that it serves well into the future.