During the night of June 18, 2001, a fire broke out at a paper mill in the Aisne department, which housed electrical transformers containing pyralene. Since rescue workers and the general public may have been exposed to PCBs and dioxins, the Prefect implemented health monitoring and protection measures. The Interregional Epidemiology Unit (CIRE) was called upon to provide support throughout the duration of the incident. After the factory reopened, the unit was asked to review the management of the accident and assess exposure levels. Methods: To address the first objective, all documents produced during the incident were reviewed, and relevant agencies (DDASS and DRIRE) were interviewed. For the second objective, population exposure was estimated based on dioxin and PCB measurements taken in the atmosphere, soil, and vegetation on the one hand, and dietary habits and physiological parameters on the other. Results: The Prefect convened a crisis unit to which the Departmental Directorate of Health and Social Affairs was belatedly added. The main decisions were to provide medical monitoring for the exposed population, ban the consumption of locally produced plants, and carry out environmental decontamination. Acute exposure for individuals exposed through dioxin inhalation during the few hours of the fire was estimated at 0.0007 pg TEQ/kg/day for an active adult (firefighter). Acute exposure via ingestion, for individuals who consumed only fruits and vegetables produced in the area, was estimated, for the 48 hours preceding the consumption ban, at 4.7 pg TEQ/kg/day for adults and 9.4 pg TEQ/kg/day for children. Chronic exposure for children aged 2 to 6 years via ingestion of contaminated soil dust was estimated at 0.0467 pg/kg/day, assuming dust ingestion of 400 mg. Discussion: Based on the exposure estimates, it appears that the control measures were sufficient. However, the delayed alert from the DDASS led to medical monitoring of too many people. Exposures related to the fire were low, and consequently the added risk is likely very low. In the "threshold-based" approach (WHO), the exposure level is below the acceptable daily intake, for both acute and chronic effects. In the “no-threshold” approach (US EPA), for a child’s exposure through ingestion of soil dust over 4 years, the excess lifetime risk would be 0.000019. Conclusion: Following this incident and its investigation, we recommend conducting a rigorous scientific risk assessment during such events, as this helps put the risk into perspective and facilitates public understanding and management by administrative authorities. To this end, public health officials must be involved in the management of the event from the outset. (R.A.)