AboveAll - thanks for the helpful OSHA link. I hope you don't mind me posting some of the details here, for ease of reading. The OSHA summary distinguishes between "respirators" (those hard mask coverings for the nose and mouth) and "surgical masks" (the masks we don at the CF Clinics). It seems that generally the surgical masks are designed to limit the transmission of "infectious respiratory secretions to others" but do not generally limit the "inhalation of small airborne contaminants". Apparently only a properly fitted and well chosen "respirator" can do that. That's good to know. It also explains that a surgical mask's "ability to filter small particles varies significantly based upon the type of material used to make the surgical mask, so they cannot be relied upon to protect workers against airborne infectious agents." They must also be FDA approved to be marketed as surgical masks. I can imagine that drawing on them with innocuous agents would not be a problem, but I wonder if some of the decorative ones are actually made out of materials suitable for a CFer's purpose. I recognized that some of them were marketed as face warmers for people in winter - which is obviously not the purpose we seek. It makes sense to me to check with your CF Clinic or health care provider to see if your homemade or purchased decorative mask meets the requirements!