The 'Sendzimir' Steel Mill, Cracow, Poland, gives employment to approximately 17,000 workers. During the years 1994-98, 1396 compensation claims for diseases related to occupational hazards were registered. After a scrupulous investigation, 851 cases were certified as occupation-related diseases. Of this number, 481 cases (56.5%) were diagnosed as pulmonary diseases, including silicosis (n = 225, 46.7%); chronic bronchitis (n = 138, 28.7%); lung carcinoma (n = 59, 12.3%); epithelial cancer (n = 42); adenocarcinoma (n = 12); microcellular carcinoma (n = 5); asthma, 12 atopic and 24 non-atopic (n = 36, 7.5%); and asbestosis (n = 23, 4.8%). Chronic bronchitis was diagnosed in patients exposed to industrial dusts, containing SiO2, NOx, and SO2. Asthma occurred most frequently among those exposed mainly to Cr+6, Co and Ni containing dusts, and lung carcinoma in those exposed to policyclic aromatic hydrocarbons, including benz(a)pyren, asbestos, chromium, vapours of oils and lubricants. In 1994-96, chronic bronchitis and silicosis, and in 1997-98, lung carcinoma and asthma were most frequently diagnosed in the workers under study. It is likely that the diminishing frequency of chronic bronchitis and silicosis was the consequence of technological progress, and greater concern for hygiene standards. Increasing incidence of lung cancer reflects long latency characteristic of this illness.