Oily rags can catch fire on their own
Why rags used with some stains and finishes heat up, and what fire officials say to do.
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Why rags catch fire
Massachusetts' Department of Fire Services says: "The oils in some paints, stains, and varnishes release heat as they dry. If oily rags and applicators are left in a pile, a box, or the trash, the heat can remain trapped and cause a fire that quickly spreads to nearby combustibles." Follow the label and your local fire officials.
What Massachusetts says to do
Massachusetts' Department of Fire Services says: "Instead, hang them outside to dry in a safe area or spread them out flat, making sure they are weighted down. They should not be in a pile."
Occasional users
Massachusetts' Department of Fire Services says to "store dry rags in a small, airtight, non-combustible (such as metal) container with a tight-fitting lid," to "Cover the rags completely with a solution of water and an oil breakdown detergent," and to "Dispose of the container during a household hazardous waste collection event."
Frequent users
Massachusetts' Department of Fire Services says those who use oily rags daily or weekly should place dry rags in a listed oily waste container emptied by a private contractor.
Colorado's warning
Colorado's health department says rags with solvents or "some wood preservatives and stains" "may spontaneously burn if the rags aren't stored properly," and that rags should be hung outside or spread out to dry "on a nonflammable surface outside away from your house and other outbuildings," in an area away from potential ignition sources, children, and pets.
A crew's rag that caught fire
The National Park Service describes a linseed oil rag placed "outside to dry flat on a workbench" that "caught fire." NPS says that for a project at home, you should "spread the soiled rags in a single layer on concrete to prevent the buildup of heat and allow the rags to become hard and brittle," and "Place the rags out of direct sunlight and secure the corners to prevent movement by wind."
Your local rules
Follow the label and your local fire officials. Their instructions control.
This is general information, not legal or safety advice.
Sources: Massachusetts Department of Fire Services (mass.gov), Disposing of oily rags; Colorado Department of Public Health and Environment, Preparing products found in your garage for disposal; National Park Service, Fire Prevention 52: Spontaneous Combustion, Fact or Fiction?.
FAQ
General information only. Follow every product label and increase ventilation when you finish, as EPA advises. State fire and health agencies warn that rags used with some oil-based stains and finishes can catch fire on their own: never leave them in a pile, and dry and dispose of them as the label and your local fire officials direct. CPSC says to anchor furniture with drawers, doors, and shelves to the wall. In an emergency, call 911.
Next: oil finishes
The rag warning comes first.
