The introduction of new technology to society often brings great benefits but it can also create new risks. Serious efforts have been made to assess and manage these risks. Perhaps the most notable example is the probabilistic risk assessment. However, these and other risk analysis methods have limitations. By reviewing how the Fukushima Daiichi nuclear accident could fall through the cracks of risks assessments, some of these limitations are discussed. Naturally, this is not intended to dismiss risk assessment but rather to make engineers more aware of what assessments can and in particular cannot do. Moreover, risk assessment methods have been criticized for ignoring the social and ethical aspects of risk. The ethical issues associated with risk analysis are discussed, distinguishing between individual-based approaches to ethics of risks (e.g., informed consent) and collective and consequence-based approaches. The chapter further reviews several methods for dealing with uncertainties in engineering design and applications, including redundancies, barriers, and safety factors as well as the Precautionary Principle and Safe-by-Design.

The process of medication management in anesthesia is both complicated (numerous steps) and complex, in that it requires continual adaptation to a continually changing environment. In addition, medication safety depends on systemic factors, some of which involve processes far from the clinical interface. The system in which medications are managed is complex, if only because humans are a key part of this system. The processes of human cognition are particularly complex, and include knowledge, evidence, information, wisdom and expertise. These processes are explored in some detail, including a discussion of short term and long-term memory. Each practitioner responds to an internally developed mental model of the current situation, which may differ considerable from that of other team members. An understanding of complexity and human cognition may often provide an explanation for failure in healthcare: such an understanding provides a foundation for our overall pursuit of medication safety.