I would imagine ANY dust in the lungs would lead to resperatory problems. Balsa dust will affect asthmatics. Paint, most types, or "coatings" as they are now called, give off particles in suspension (fumes) and epoxy spraying is considered a grade one hazard in industry. We dice with death in the "ordinary" thing we use in modelling never mind the razor blades,whirling props,crashing planes. Our fuel (methanol) is an absorbsion poison and we casualy wipe it off our hands with a rag ! Geez...wish I could give up smoking, makes me so depressed/depressing. Oh well back to the building board .
