Fire broke out on a distillation column down for repairs within a salicylic acid workshop of a chemical plant. The fire spread to the entire column and in particular to the instrumentation ducts, heat insulators and electrical cables. The blaze was extinguished by the site’s internal fire-fighters 13 min after its initial ignition. Damage was limited to the specific unit, with no environmental impact being recorded; extinction water was recovered in the workshop’s retention basins.

The ignition of phenol vapours caused this accident. The unit had, since the previous day, been partially shut down (the distillation column was offline but the remainder of the unit was maintained in pressure and temperature) following the detection of a phenol leak on a flange at the column base. That morning, a subcontractor performed repairs using an impermeable resin. During column pressurisation testing with water vapour, a new leak was detected at the level of a valve. The operator then decided to disassemble the lower heat insulator on the column to allow for repair work to proceed. During this operation, phenol vapours entering into contact with metal on the column (temperature reading: 78°C) ignited. The unit was shut down for 4 days to clean and refurbish the installation.