Five cases of pneumoconiosis in carbon electrode manufacturing workers were described. Exposures and potential exposures in the facility employing these workers included coke (65996772) dust, pitch (65996932) fumes and dust, silica (14808607), graphite (7782425) dust, and asbestos (1332214). Cases were all male with ages of 49, 70, 64, 67, and 58 years at first examination. Two were lifelong nonsmokers, and job tenures ranged from 24 to 35 years. Chest auscultation, chest x-rays, and pulmonary function tests were carried out. Auscultation was normal in one case, revealed fine basilar crackles in two cases, and indicated hyperresonance in two. Variable radiographic abnormalities were noted. Small opacities were generally of the linear/irregular type. Small rounded opacities but no large opacities were seen. One case showed normal spirometry results, and two each showed an obstructive or restrictive pattern. Three had impaired gas exchange. Lung biopsy material was examined in detail in one case. Considerable birefringent crystalline material was present; the amount of free silica was less than that noted in typical simple silicosis. A coarse black pigment, probably carbon (7440440), and fibrous aluminum-silicate (12141467) predominated. A mixed dust exposure was suggested. The authors conclude that these cases suggest that pneumotoxic exposures in this industry continued at least into the early 1960s and that control measures should be evaluated for efficacy.