04 Aug The Dangers of Oily Rags

The Dangers of Oily Rags

Oily rags may look harmless, but improperly stored rags can create a serious fire hazard. Certain oils, paints, stains, and other products can generate heat as they oxidize. When contaminated rags are piled together or improperly stored, that heat may become trapped and build until the material ignites—even when there is no spark or open flame.

This process is known as spontaneous heating and can result in spontaneous ignition.

Guide for Discussion

How Spontaneous Ignition Occurs

Some oils and other materials react with oxygen in the air through a process called oxidation. Oxidation can generate heat.

Normally, this heat dissipates into the surrounding air. However, when oil-soaked rags or similar combustible materials are piled together, the heat may become trapped. If heat is generated faster than it can escape, the temperature can continue to rise until the material ignites.

This is especially dangerous because a fire may develop hours after the work has been completed, when no one is nearby to detect it.

Materials That May Present a Hazard

Materials that may be capable of spontaneous heating include rags, towels, wipes, clothing, or other combustible materials contaminated with certain:

• Drying oils, such as linseed or tung oil
• Oil-based paints and stains
• Varnishes and finishes
• Wood-finishing products
• Vegetable oils
• Solvents or other flammable or combustible products
• Paint or coating residues

Not every oily material has the same potential for spontaneous heating. Always review the product’s Safety Data Sheet (SDS) and follow the manufacturer’s storage and disposal instructions.

Safe Storage of Oily Rags

Do not leave oily or solvent-contaminated rags:

• In piles
• On workbenches
• In ordinary trash cans
• In cardboard boxes
• On or near combustible materials
• Near heaters, hot equipment, welding operations, or other ignition sources

At the workplace, place combustible waste and oily rags in approved, properly designed waste containers with self-closing lids, as required by the materials involved and company procedures.

Keep containers:

• Closed when not being filled.
• Clearly identified for their intended contents.
• Away from heat and ignition sources.
• In designated locations.
• Emptied and disposed of at appropriate intervals.

Do not mix incompatible chemical wastes in the same container.

Do Not Rely on a Closed Ordinary Container

Placing oily rags in just any closed container is not an adequate control. The container must be appropriate for the material and intended for the safe collection of oily or combustible waste.

Similarly, do not assume that simply spreading contaminated rags out to dry is an acceptable workplace disposal method. Drying, storage, and disposal must follow the product manufacturer’s instructions, SDS, company procedures, and applicable fire and environmental requirements.

Housekeeping Is Critical

Good housekeeping is one of the most effective ways to prevent fires involving oily waste.

• Clean up oil, paint, and solvent spills promptly.
• Do not allow contaminated rags to accumulate.
• Place used rags in the designated container immediately after use.
• Keep combustible waste away from hot surfaces and ignition sources.
• Regularly inspect oily-waste containers.
• Remove accumulated waste from the work area according to established procedures.
• Report damaged, missing, or overflowing waste containers.

Before Leaving the Work Area

At the end of the task or shift, take a moment to inspect the area.

Ask:

• Have all oily rags and wipes been collected?
• Are they in the proper container?
• Is the container lid closed?
• Have spills and residues been cleaned up?
• Are combustible materials separated from heat and ignition sources?
• Does any waste require special handling or disposal?

A few minutes of housekeeping can prevent a fire that might otherwise develop after everyone has left.

Remember

Oily rags can start a fire without an external ignition source. Never leave oil-soaked or chemically contaminated rags piled together or dispose of them in ordinary trash.

Place them in the approved container designated for oily waste and follow the SDS, manufacturer instructions, and company procedures for storage and disposal.