A flash inside a plant manufacturing solvent resins for paints injured 2 employees. The damaged reactor was producing resins for decorative paints in 10-tonne batches. Once ester production had been completed, 400 kg of xylene were added to eliminate the water; 75% of the xylene was then eliminated by vacuum sealing. The preparation step ended by manually adding polyamide granules via the manhole. Though the reactor had been nitrogen-inerted, xylene vapours created an explosive atmosphere around the manhole. An unknown source of inflammation ignited this mix. Both technicians stationed nearby and sustained facial burns requiring hospitalisation. The paper bag containing polyamide granules, placed next to the manhole, was struck by the fireball but did not combust and was partially blackened. The reactor was switched to safe operating mode (by draining its contents). The Inspection Authorities for Classified Facilities asked the plant operator to submit a report analysing the deficiencies leading to this accident. The reactor operating protocol had to be changed; the insertion of polyamide, the lone remaining manual operation in this process, was earmarked for automation.