Baritosis: a benign pneumoconiosis.

Baritosis is one of the benign pneumoconioses in which inhaled particulate matter lies in the lungs for years without producing symptoms, abnormal physical signs, incapacity for work, interference with lung function, or liability to develop pulmonary or bronchial infections or other thoracic disease. Owing to the high radio-opacity of barium, the discrete shadows in the chest radiograph are extremely dense. Even in the most well-marked cases with extreme profusion of the opacities, massive shadows do not occur. When exposure to barium dust ceases the opacities begin slowly to disappear. Nine cases of baritosis occurring in a small factory in which barytes was crushed, graded, and milled are described. Two of the cases occurred after only 18 and 21 month's exposure, and 9 of the 10 men employed for more than one and a half years had baritosis. Five of the affected men examined at intervals since their exposure to barytes ceased in 1964 showed marked clearing of their radiological abnormalities.