Some systems failures are due to defects in manufacturing and design, however that there are a significant number of system failures which result from errors, omissions and inconsistencies in the system requirements. We thus need methods to support a `safe' requirements engineering process whose objectives are to specify system requirements such that system states which compromise safety are avoided and to include, along with the requirements, a justification or safety case which explains why the specified system is indeed safe. This paper describes the extension of a viewpoint-based requirements method to incorporate safety analysis.