In an oil de-waxing unit, a pool on fire was detected a little before 6.00 am at the foot of an oil/ammonia cooler that was neutralised the previous day following the detection of a hydrocarbon leak. The fire spread to an area of 50 m² and damaged the electric cabling, piping, neighbouring valves and fittings and four heat exchangers. The internal emergency plan was triggered and the fire-fighters brought the fire under control at 6.18 am. No casualties or pollution were reported. The economic impact, mainly due to the damage caused to the equipment and loss of production due to shutdown of facilities was assessed at 400 k euros. More than 12 hours before the fire, the technician had repaired a leak after draining and emptying hydrocarbons and crystallisable paraffin. The paraffin may have partially solidified in the heat insulator protecting the device thus retaining several hundred litres of solvent. During the previous night, heating with steam would have caused the most volatile substances in the insulator to evaporate. Heat tracing had triggered a wick fire phenomenon that liquefied the set paraffin and released around 2 tonnes of an already ignited mixture. The operator implemented measures to avoid similar accidents from reoccurring.