Handling oily rags: storage, self-ignition and disposal

Why rags ignite on their own

Some oils dry by reacting with oxygen in the air. These include linseed and tung oil, boiled linseed oil, oil paints, and oil-based varnishes and stains. This oxidation releases heat.

A single rag laid flat has time to cool. In a pile or a bag, the heat builds up. The temperature keeps rising until the fabric bursts into flame. Sometimes this takes several hours — at night, when nobody is in the workshop.

Joinery and paint shops, furniture workshops and ship repair yards are most at risk — wherever varnishes and oil finishes are used.

What about engine oil?

Mineral oils — engine, hydraulic and gear oil — hardly self-heat. But oily rags burn very well. A spark from a grinder or a hot part nearby is enough. So the storage rules are the same for all oily rags.

How to store them on site

• Only a closed metal container with a lid, ideally self-closing. Not a plastic bucket and not a bag.
• Keep the container away from clean rags, solvents and heat sources.
• Before disposal, lay rags with linseed oil, varnish or stain flat to dry outdoors. Or put them in a metal container filled with water and close it.
• Empty the container at the end of every shift. Never leave rags overnight in a pile, on a workbench or in a workwear pocket.
• Keep the container away from welding, cutting and grinding.

Disposal: the waste code

In the European List of Waste, rags contaminated with hazardous substances have code 15 02 02*. The asterisk marks hazardous waste. Oils, fuels and solvents make rags hazardous.

Rags without hazardous contamination are code 15 02 03. They go with ordinary industrial waste.

Hazardous waste must not go into a general bin. Hand it to a company with a hazardous waste permit. In Estonia, the transfer is documented with a hazardous waste transfer note (ohtlike jäätmete saatekiri).

Workshop checklist

• A metal container with a lid at every station where oil or varnish is used.
• A label on the container saying what goes in.
• A named person who empties it at the end of the shift.
• A contract with a hazardous waste handler and a collection schedule.
• Clean rags stored separately, in closed packaging.

Clean rags are part of good housekeeping

We supply dry, sorted wiping rags in 10 kg bags. Keep the bag closed until use, away from the waste container. To pick the right grade, read types of wiping rags.