It is increasingly clear that data, not just systems and software, can be a safety problem and the SCSC has recently promoted efforts to look at the issue of data in safety systems. This started with a seminar ‘How to stop data causing harm’ held in December 2012 and has progressed with 6-weekly meetings of a working group during 2013. The group, comprising industry, academic, government and independent consultants is producing a guidance document, entitled ‘Guidance for management of data where safety is an issue: managing the risks of dataware in safety-related and safety-critical systems’. The objective of the guidance is to describe the safety data problem, and initially, for key data types and lifecycles, provide methods for defining the level of risk and recommended strategies for safety risk reduction. This paper presents the progress in developing this guidance, and provides an outline of the next phase of this work, which will include production of supplementary material for incorporation into existing safety standards.