The recent assessment carried out by BARPI shows an increasing evolution of accidentology in classified installations in France with a predominance of fires. In order to characterize their possible impact on the environment and the population, it is essential to collect as quickly and reliably as possible the data relating to the event. Measurement and sampling campaigns are then necessary in order to know the substances emitted, the areas of fallout and to build an adequate sampling plan. The DESIHR project (Swarm Drones for the air Monitoring of High Risk Industrial Sites) aims to study the contribution of new technologies to characterize in real situation and more quickly the substances present in a fire plume and their emission conditions in order to carry out predictive mapping of their propagation. It is based on the use of a fleet of autonomous UAVs capable of adapting its flight plan according to the information acquired by each UAV, in order to fulfill two missions which will consist of : - positioning itself in the plume dispersion axis at increasing distances from the source in order to take samples (coupling micro-sensors, automated opening canisters) that can be rapidly analyzed on the ground thanks to a portable GC/MS for gases and soot (granulometry, chemistry, electron microscopy) in the laboratory. The chemical characterizations will allow to evaluate the dilution rate and flows on vertical sections of the plume. - acquire video images of the plume from outside the plume simultaneously from different viewing angles. This information will be transmitted live (crisis cell) so that image processing can be used to determine parameters useful for plume modeling (plume height, volume, section and shape of the plume, etc.). It is broken down into five tasks : - to select the most relevant UAV payloads for the missions and to define the flight strategy with a swarm of UAVs with regard to various constraints (regulatory, aggressive environments, etc.); - to implement algorithms defining the collective actions of the UAVs, the flight controls and the flight plans. This will provide a fleet of autonomous UAVs whose behavior will be based on the data acquired by the payloads integrated into them; - mechanically integrate the capture systems with the UAVs and perform the electronic interfacing of the capture systems; - set up experiments where the generation of artificial model plumes is controlled. This will then provide a controlled and simple framework for evaluating the performance of the payloads used, the performance of the collective actions undertaken by the UAVs, and finally, the relevance of the approach to the final challenges of chemical analysis and modeling; - to carry out a demonstration in a realistic situation undertaken on the SDIS76 exercise platform in Le Havre, the results of which will make it possible to study the possibility of an industrial valorization of the technological solutions proposed by the project. This project is multidisciplinary, bringing together skills in crisis management, robotics, automation, servo-control, mechanics, metrology of atmospheric pollutants, image analysis, atmospheric modelling and air quality. To cover these fields of expertise, six partners are directly involved in the project. A balance has been found between research and development approaches and representation of end-users and distributors. The project will also benefit from the support of the members of the Normandy UAV Innovation Center (CIDN, 7 founding players including: ULHN- NAE - Le Havre Seine Développement) via access to certain shared equipment (UAVs, simulators) and CIDN resources (indoor/outdoor flight zones).