Until the 1990s, decontamination was limited to the tasks of ABC units in disaster relief. Today, decontamination measures are considered one of the fundamental tasks in ABC operations. Recent events, such as the emergence of avian influenza, demonstrate that an ABC operation without decontamination is no longer conceivable. The aim of this Red Book is to present not only the essential scientific foundations but also practical decontamination options that can be implemented with the existing resources of fire departments.