In order to produce slabs, billets or blooms, molten steel is poured into large ingots or continuously cast. The size of the ingots or other cast material is reduced by rolling mills, meanwhile, these materials are shaped into usable products.

Considerable amounts of energy is required by the rolling process. The rolls is turned by high horsepower motors, and other mill equipment is controlled by high-pressure hydraulic systems. There are kinds of rolling fluids on steel mills, such as water, water-oil emulsions, water-glycol solutions and petroleum-based products.

The rolling process generate heat from hot-rolled steel and frictional heat causing the rolling fluid to evaporate. Some may splashes off the running rolls. If oil or glycol are contained in the rolling fluid, these materials will gather on cooler building, equipment surfaces and inside fume exhaust systems, where they may be ignited. The possible fuel sources also include hydraulic fluids, lubricating oils and greases.  

Large dollar loss exposures may be caused by mechanical breakdown of rotating mill parts and electrical breakdown of large electric motors. Fire protection systems of steel rolling mill should include the building, the mill itself, mill motors and gears, oil cellars, pits, hydraulic systems, fume hoods, exhaust ducts, scrubbers and precipitators. The gears, rolls, motors and all ancillary equipment necessary for running the mill are supposed to be protected against mechanical and electrical breakdown.