Proper storage and disposal of used cleaning products and other cloths are important at any workplace, not just for hygienic reasons but also, sometimes, for fire safety. Oil-soaked and solvent-soaked rags present a serious fire hazard, and in the case of oil-soaked rags, a spontaneous combustion hazard as well. Safe disposal methods as outlined and required by the Occupational Safety and Health Administration (OSHA) are key to preventing fires in the workplace.

It may sound surprising that an oil-soaked rag could spontaneously combust. Rags used to wipe up spills, clean brushes, or anything else involving painting, staining, or varnishing can absorb significant amounts of oil, which releases heat as it oxidizes. When the heat has no way to dissipate, it builds to the point where it can ignite a flammable cloth rag. Storing used rags with no way to vent this heat, such as in a sealed bin or even a pile of other rags, creates an insulating effect that accelerates the process; ambient heat from machinery or steam lines, or even warm, dry weather can also impact combustible materials. Even something as simple as crumpling or wadding up a used rag can cause dangerous self-heating! Many DIYers have stories about finding a single used rag left undressed had begun to smolder or was painfully hot to the touch.

According to a study by the National Fire Prevention Agency (NFPA), there were 36,784 reported fires at industrial or manufacturing properties from 2017-2021. Of these fires, 20% involved trash or rubbish. This isn’t a problem unique to workplaces, as the NFPA also records an average of 1,700 spontaneous combustion home fires per year, 900 of which are caused by oily rags.

How should you dispose of oily rags, then? OSHA 29 CFR 1926.252(e) indicates that, “all solvent waste, oily rags, and flammable liquids shall be kept in fire resistant covered containers until removed from worksite.” Although solvent-soaked rags are typically not a spontaneous combustion risk, they’re a fire risk and a potential respiratory hazard as their chemicals evaporate. An OSHA-compliant oily waste can is the best way to store these materials. These cans will be fire-resistant, made of a material like steel, and have a lid that automatically closes and only opens to a maximum of 60° in order to protect the contents within from ignition sources like sparks. They’ll also be round and have ventilated bases to encourage air circulation that disperses the heat created by oil-soaked rags. Placing these bins around your worksite, away from ignition sources, as well as daily emptying of the bins will help ensure safe storage of used flammable waste before it can be properly disposed of.