An assessment, including questionnaire and spirographic measurements, was conducted on the respiratory health status in 54 male swine producers, aged on average 36.3, who worked an average of 10.7 years in the industry and spent on average 4.7 hours per day in the swine barns. Atmospheric contaminants were measured including carbon dioxide, ammonia, total dust, respirable dust and airborne endotoxin. Respiratory symptoms and lung function studies did not relate to categories of low, medium and high exposure to respirable dust. The data suggest that respiratory health status relates to endotoxin levels but not to dust level exposures in the presence of low dust levels and indicates that control measures should include endotoxin as well as dust control.