A longitudinal study of pulmonary function and radiological change has been conducted on 141 nonsmoking coal miners and 256 smoking coal miners from Lorraine, France. At the time of the first examination occasioned by radiological change or shortness of breath, the men averaged between 46.6 years and 50.9 years of age, and they retired approximately 8 years after entering the study. They have been followed for average periods of about 18 years and a mean of five FEV1 observations per man were made over that period. Changes in radiological category have been documented. Average rates of decline of FVC and FEV1 were similar, and varied between -47 ml/yr in nonsmoking miners still alive, to -78 ml/yr in deceased smoking miners. These accelerated rates were similar before and after retirement from the mine.