Non-expert summaryThe management of decontamination of the population (who were mobile enough to walk through a showering lane) in the event of a large-scale chemical release in the UK was modelled, based on data collected in field trials. The movement of volunteer casualties at two mass decontamination field exercises was monitored using passive Radio Frequency Identification tags and detection mats. The data were used to inform a computer model of the UK fire and rescue service component of the mass decontamination process. This identified bottlenecks in the process and led to recommendations for change, particularly in the re-dressing part of the process.