There are questions to ask first. 

1. What where the rags used for?  For example, if they were used to clean up after oil painting, they also contain some oil and can spontaneously combust.

2.  How tight is the lid?

1.  The turpentine has an air quality standard of 20 ppm (TLV-TWA).  If this is a painting class and real turpentine is used at everyone's easel, it is very likely the whole class is over exposed to turpentine.  It takes an incredibly fast air exchange ventilation system to keep up with a solvent this toxic.  If they would switch to Gamsol or Isopar L that has a TLV-TWA of 100 ppm, that would be much safer.  And these solvents work the same.

The factors that make spontaneous combustion more likely are the present of linseed or any natural (unsaturated) oil, any drying agents, or paints that contain oil and/or metal pigments that act as drying agents such as compounds of manganese, cobalt, some iron forms, etc.

2.  The lid needs to be really tight if there is oil, varnish, or oil paint present to insure the rags don't catch fire.  If there is no oil source on the rags then the only problem would be the escape of the turpentine vapors contaminating the air in the room all night.  The tighter that lid fits, the better. If the lid is tight, there is no problem leaving the rags overnight.  (In my experience that wait in the can is usually a lot longer than overnight.)

There also may be an issue with how Facilities disposes of them.  But at least the is no longer in your lap.

Monona

On Monday, August 26, 2024 at 10:16:31 AM EDT, Tricia Hahn <thahn**At_Symbol_Here**jbu.edu> wrote:

I'm looking for information on solvent-soaked rags protocols. 

Our art department collects them in the red metal cans with a lid - turpentine soaked. Their question is whether it's ok for them to be left in the can overnight. The facilities staff pick them up in the morning. I can't seem to find clear direction on that.

Thank you!

Tricia Hahn

John Brown University

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