[Prevalence of pneumoconiosis in workers exposed to phosphate rocks].

The occurrence of pneumoconiosis among workers at a phosphate rock mill in Paulinia, S. Paulo (Brazil), is analysed. Among the 73 exposed workers the occurrence of 20 cases of pneumoconiosis (27.4%) is registered. Beyond the physical examination, the investigation included spirometric examination, thorax X-rays, and lung biopsies during thoracotomy. The majority of the pneumoconiotic workers were assymptomatic with mild alterations in the spirometric pattern, mainly in the maximal medium expiratory flow, with 2 cases of restrictive pattern. The two lung biopsies did not reveal any degree of fibrosis and the analysis of the inhaled material, using X-ray spectrometry and colorimetric method, did not show enough SiO2 to promote fibrosis. It is concluded that the pneumoconiosis in question must be included in the non-fibrogenic group until further investigation can be made, by prospective research.