Glass wool or vitreous fibers are non-crystalline, fibrous inorganic substances (silicates) made primarily from rock, slag, glass, or other processed minerals. They belong to the man-made mineral fibers (MMMFs) group and their respiratory effects are well described by De Vuyst et al. . The authors pointed out the absence of firm evidence that exposure to these fibers is associated with lung fibrosis, pleural lesions, or non-specific respiratory disease in humans. Because of this observation, we find it of importance to present a case of interstitial fibrosis, which implies a direct association between long-term exposure to glass wool and the clinical outcome.