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.