How is engineering safety best served by forensic science and engineering that pertains to legal processes? A critical question for a lawyer is ‘who is trying to do what to whom?’ The primary concern of the court is not an abstract inquiry into the causes of an incident but to establish who is to blame. Failure is essential to the growth of knowledge. As failure is exactly what engineers do not want it is all the more essential that we learn lessons when it does happen. Technical reports are embedded in human and social systems and so forensic engineers must be sensitive to semantic subtleties regarding error, mistakes, accidents and disasters. Models of how ‘latent’ hazards, technical and social, are given, but all require engineers to think in an integrated way – to cross disciplinary boundaries between ‘hard’ physical technical systems and ‘soft’ managerial ones. This may be facilitated by systems thinking – a way of looking for commonalities, dealing with dimensionality, multiple perspectives and looking for alignment between fragmented professional and social silos.