In hazardous industries, disasters are mercifully rare and yet the potential is ever present. For this reason, companies and industries as a whole put substantial effort into gathering information about past small failures and their causes in an attempt to learn how to prevent more serious events. Despite these efforts, recent research has captured how organizations can ‘fail’ to learn. Disastrous events can become ‘black swans’ and remain unpredicted despite the existence of information warning of them. This article engages with this challenge by analyzing incident-reporting systems as a tool for collective knowledge. Drawing together the literatures on organizational knowledge management and incident reporting, we examine incident-reporting systems as used and as structured. We explore the potential use of incident-reporting systems for mediation and synchronization of knowledge within and across groups of professionals and organizations. We also address the social practices that translate information in databases into collective knowledge. Building on the work of Hecker, we argue that research concerned with incident reporting and organizational learning would benefit from using ‘knowledge’ and specifically ‘collective knowledge’ as its reference point. We show that conceptualizing this problem in terms of ‘reporting’ and ‘learning’ distracts attention from the knowledge needs for people to learn. We argue that we must ask: What do people need to know to play their part in major accident prevention? And how is that knowledge effectively shared? We conclude with an empirical research agenda in light of this investigation.