How might we assess expert opinion and convergence on risky matters? Shanteau [17] points to the importance of the level of decision, made by experts using a medical analogy of diagnosis (what is it?), prognosis (what is the likely outcome?) and treatment (what to do about it?), with a different logic applied on different levels. Furthermore, experts and professionals possess similar cognitive properties as non-experts. "Experts are not immune to the cognitive illusions that affect other people" [27] . And it is increasingly noted that cognition and emotion are intertwined in decision-making (see [28] ). As Cross [29:28] comments: "when an attitude or an activity is of considerable importance to a person, the individual is loathe to believe that it is hazardous." Furthermore, biases or heuristics found in studies of perceived risk may be found among experts and affect their assessments and opinions. In this paper, we address some of these issues about expert opinions, utilising the ideas of non-convergence (especially at different levels of an assessment), and of the heuristics made by different professional groups (commitment to a particular practice, reliance on rational models and thinking), to understand different concepts of risk relating to the blood supply arising from a case when supply of 'safe blood' was potentially disrupted in one Canadian city. So all may want 'safe blood' but do the management and decision-making styles and discourses of all actors converge or vary?