In a plant manufacturing chlorine pellets for swimming pools, combustion occurred in a hopper feeding a compression machine performing the pelleting step. Three workshop employees noticed smoke emanating from the machine booth and the overhanging feed cone. Fire-fighters were notified, the internal emergency plan was activated and the 10 employees all evacuated factory premises. Equipped with full-face masks, 4 of them returned to: remove packaging placed near the machine (cardboard boxes, plastics, chemical products, etc.), disassemble the front part of the booth, and collect the substances burning in the barrels in order to prevent the fire from spreading. The 300 kg of raw materials present (mix of dichloroisocyanuric acid / sodium bicarbonate / adipic acid) were in the final phase of combustion 20 min after the initial outbreak. The mechanical smoke exhaust ducts minimised the accumulation of white smoke in the workshop, and a cloud began to drift outside. The combustion ashes were extracted from the machine and stored in metal cans. Fire-fighters, who arrived at the scene 20 to 25 min after the alarm was sounded, entered the workshop with self-breathing apparatuses in order to assess the extent of the damage. With approval of the plant owner, they did not use water to extinguish the blaze, as hydrolysis of the involved substances would have triggered a release of toxic smoke and chlorinated gases. Wearing chemical protection suits, they progressed into the workshop to conduct sampling; the analyses were all negative. Production was suspended for 12 hours, but the production line was not fully restarted until 48 hours later. A visual inspection of the facilities revealed a trace of circular heating on the paint seen on the motor block of the chemical product conveyor. Disassembly of the system exposed a decoupling between the conveyor and the motor. The auger/motor shaft anchoring bolt had broken, after which it rubbed during part rotation against the metal wall of the drive tube. The induced heating caused dust from chlorinated substances to ignite. The factory plans developped preventive maintenance controls for high-risk parts in the aim of gradually improving its facilities. Guidelines were modified. Authorised to store 200 tonnes of combustive matters, in accordance with the “SEVESO upper-tier” threshold, this site was required to institute an external emergency plan.