It is uncertain who will assist the victims of use of nuclear, radiological, biological or chemical weapons if an international response is required, and how this assistance can be provided without undue risk to those providing it. The use of such weapons or any other release of the materials of which they are composed cannot be considered as presenting a uniform risk. There are a variety of risks, each with its own implications for getting help to the people affected and for the health and security of those bringing that help. The political implications are serious and complex. This brief review shows the difficulties inherent in assisting the victims or potential victims of use of nuclear, radiological, biological and chemical weapons.