Fire Chief Warns Of Spontaneous Combustion From Cooking Oil-Soiled Rags

(Beaver Dam) The Beaver Dam fire chief says there has been an increase in the number of fires caused by spontaneous combustion from oily rags. Once thought to be an industrial or wood shop issue, Chief Alan Mannel says there has been an uptick of such incidents in kitchens, taverns, laundromats and restaurants.

A local bar and grill recently had a close call. There was a slight smell of smoke and patrons complained of burning eyes. Fire officials used a thermal imaging camera and noticed that a stack of towels was warm. When the towels were moved, they burst into flames. Upon further investigation, Mannel says he discovered that the towels had been used to clean up cooking oils and that fuel, combined with heat and oxygen, is a recipe for fire.

In that incident, the oxygen came from disturbing the towels. The heat was produced through the breakdown oxidation of the remaining cooking oil in the towels, specifically animal and vegetable-based cooking oils. Heat can also be produced in a clothes dryer.

Mannel says most people do not realize that cooking oil is moderately-to-highly susceptible to supporting spontaneous combustion. Just ask any farmer about storing wet hay, he says, as dried out hay decomposes and causes heat. If the heat is not allowed to dissipate, it can rise high enough to ignite combustibles.

Mannel says that modern, high-efficiency washing machines could be part of the reason for the increased fires. He says they do a good job with most items but not on soiled rags and towels containing cooking oil, especially when cold water is used which locks in the remaining oils. In addition, detergents used for ordinary fabrics do not remove all of the oil.

Mannel says such fires can be prevented by presoaking rags, laundering rags in commercial washing machines, using commercial solvents to remove residual oils, washing twice, using hot water, air-drying on a clothes line or a medium heat setting, allowing to cool after drying, storing in metal cabinets with air flow, allowing rags to cool to room temperature before folding and disposing of heavily-soiled rags and towels.