Photomicrographs of lung tissue from welding fume-exposed A/J mice. Preneoplastic lesions (panel A) and adenomas (panel B) were the most common lung lesions observed in all exposed and sham groups. These representative low magnification photomicrographs were captured at 48 weeks post-exposure to GMA-SS fume. Panel C is a high magnification photomicrograph showing the presence of GMA-SS fume (brown-black granular pigmented areas) at 48 weeks post-exposure. An increased persistence in the lung was observed for GMA-SS fume compared to the GMA-MS or MMA-SS fume. At 78 weeks post-exposure, the presence of GMA-SS fume is still observed in the lung and an increased lymphohistiocytic infiltrate was associated with this fume (panel D).