Graphite pneumoconiosis. A review of etiologic and epidemiologic aspects.

Six hundred and five cases of graphite pneumoconiosis have been reported in the literature. In 39 cases the diagnosis was based on or supported by autopsy or lung biopsy results. Only 14 of the 39 cases were presented with relatively complete documentation as to details about dust exposure. Only one of these completely documented cases suggested that nearly pure graphite may cause graphite pneumoconiosis. Eleven experimental studies on animals dealt with the effect of graphite dust on various tissues, and nine with the effect on lung tissue. The three studies on the effect of pure or nearly pure graphite gave no unanimous conclusion. Five out of six studies dealing with graphite containing silica demonstrated fibrogenic effect on the lungs. Most of the 18 epidemiologic studies of workers exposed to graphite dust are invalid because they do not comply with ordinary methodologic requirements. The present state of knowledge does not exclude the possibility that analytically pure graphite may cause pneumoconiosis although the majority of the evidence indicates that pneumoconiosis is a mixed-dust type of lung reaction.