Ulrich Müller-Herold's paper introduces a conceptual alternative to risk analysis as the basis of risk management. Risk denotes the combination of probability times magnitude of adverse effects. Conventional management strategies are designed to reduce either one of the two components. Müller-Herold argues that the precautionary principle in environmental policy making requires an approach that implies management steps at an earlier stage. His target is what he calls "endangerment". Controlling endangerment means controlling the scope and range of the potential for damage. He develops a taxonomy of endangerment that comprises two main factors: spatial extension and persistence over time. These two factors determine the degree of endangerment regardless of their strength of destructive potential. So far the term "endangerment" lacks a well-defined quantitative meaning. Müller-Herold develops a quantitative approach and illustrates this with an example.