In a cross-sectional study, 13 nonsmoking men with heavy exposure to paper dust were compared with 14 unexposed men, mainly office workers, employed at the same paper mill. They were studied using questionnaires, physical examinations, pulmonary function studies, and chest radiographs. Among those exposed there was an increased lung elastic recoil pressure (Pel) compared with controls which was significant (p less than 0.05) at the maximal level of total lung capacity (100% TLC). Furthermore, among the exposed workers there was also a significantly (p less than 0.05) decreased residual volume (RV). Two of the exposed men underwent lung biopsies, one of which showed fibrotic alveolar walls. Among the exposed there was also a significant (p less than 0.05) predominance of symptoms from the lower respiratory tract. We suggest that the observed pulmonary function impairment taken together with the histological examination of the lung biopsies are signs of a nonspecific reaction to high levels of paper dust.