Ask the Expert Question-and-Answer Archive

by Ron Joseph

January, 2005

Health and Safety--CARC Polyurethane Overspray

Q. Does dried CARC overspray dust pose a significant health threat?

A. I do not believe that dry overspray of CARC poses a health threat. My reasons for saying this is that the polydiisocyanates in the coating (the harmful ingredients) will already have reacted either with the base component (polyester or acrylic) or with moisture in the air. Therefore, by the time someone inhales the dust it is chemically inert. This is not necessarily true of wet overspray in which the polydiisocyanate may not yet have fully reacted. This is why it is so important for painters to wear the appropriate protective clothing and respirators.

Bayer Chemicals (www.bayer.com) is the leading, but not the only supplier of isocyanates to the paint industry and I encorage you to visit their website for more information and for confirmation of my answer. You might need to scout around to find they literature.

I am not a toxicologist or industrial hygienist and therefore, speak only from experience and not with absolute chemical knowledge.

Ron Joseph