I'm having an issue at work with a specific type of dust particle. They are little black fibers that are about 20 microns wide and about 1 millimeter long. You can see them with the naked eye, barely. The problem is that when they come into contact with an organic solvent (we are working with polyurethane dispersed in DMF and MEK), they leach a bluish color in their immediate area. When they do this, the fiber remain intact. I've been wracking my brain trying to find the source of these things. Has anyone experienced this before, and can you shed any light on it?