In a cement works, a fire broke out in a boiler room releasing huge quantities of smoke. Two boilers (1 electric and 1 gas) that could not be operated at the same time were used to warm-up a highly viscous fuel. When the gas boiler was operating, the electric boiler was switched on leading to the overheating of the residual cooling fluid. There was no major environmental impact. The clinker production was stopped but not the production of cement as the plant could operate on the existing clinker stock while awaiting the necessary repair operations.