Oily Rags & Spontaneous Combustion

A pile of rags soaked with oil-based stain or linseed oil can catch fire by itself, with no flame or spark, hours after the work is done. Painters, floor finishers, woodworkers and homeowners have lost shops, trucks and houses this way.

• Painters
• Floor finishers
• Woodworkers
• Homeowners

Why it happens

Some oils harden by reacting with oxygen in the air. That reaction gives off heat. Spread out, the heat escapes. Bunched up in a pile, a bag or a trash can, the heat builds until the rags ignite.

Risky products

• Boiled or raw linseed oil
• Tung oil and Danish oil
• Oil-based stains and wood finishes
• Oil-based varnish and polyurethane
• Some teak oils and deck stains

Check the product label and SDS; many warn about spontaneous combustion.

Safe handling

• On jobsites and in shops: put oily rags in an approved oily waste can with a self-closing lid, and empty it every day. OSHA requires oily rags and solvent waste on construction sites to be kept in fire-resistant covered containers until removed.
• Other options: lay rags flat outside to dry, away from buildings, then dispose of them; or put them in a metal can, cover with water, seal it and dispose of it as local rules allow.
• Keep oily waste cans away from heat, sun and other trash.

• Don’t pile oily rags in a corner, bucket or plastic bag
• Don’t throw them in a dumpster or trash can with other waste
• Don’t leave them in a truck or trailer overnight
• Don’t put them in a dryer

Last updated: October 2, 2026