A fire broke out on the distillation tower of an atmospheric distillation unit operating normally in a refinery. The fire appeared on the valve spur of a naphtha stripper. The stripper was heat insulated till the spur. The naphtha leaked out and spread over the heat insulator that caught fire. The accident led to the temporary shutdown of installations and occurred due to the leak caused by a 6 mm crack in the ox-bow of the stripper. Corrosion was responsible for the leak.