These guidelines have been produced to help health facilities respond to and manage mass casualties in the event of chemical weapon use or the release of toxic chemical agents during an armed conflict or other violence. They aim to reduce the risk to people who have been contaminated and protect care providers from secondary contamination. The document sets out guidance and factors to consider when planning, preparing and providing pre-hospital assistance for contaminated people. It also covers the technical and practical aspects of decontamination. It does not, however, provide information on the medical training required to identify and treat chemical injuries.