Although emergencies involving mass casualties following the release of chemical or radiological agents are rare, the risks are well-recognized and many countries have prepared national response plans. The MASH (Mass Casualties and Health) study, partially funded by the European Commission, examined preparations for mass-casualty management and associated health risks within the Member States of the European Union (EU). The objective of the study was to improve the overall capacity to manage mass-casualty incidents that may equally outstretch the resources of a single country or involve several states simultaneously. Through confidential questionnaires and other means, MASH investigated the current response capabilities and planning for chemical and radiological incidents within the EU and also explored, through a number of seminars, developments in information and communications technologies, together with relevant developments in biotechnology which could improve a unified response. Finally, a foresight study has identified a number of areas for improvement and identifies six strategic aims for EU Member States to cope with chemical and radiological mass casualties. This presentation will cover the main findings of the MASH study and consider its wider message for chemical and radiological incidents worldwide.