The Pulmonary Reaction to High Concentrations of Fibrous Glass Dust

The pulmonary response, in both rats and hamsters, to the presence of fibrous glass dust, is characterized by relatively small accumulations of macrophages without significant stromal change. Whether the fibrous glass dust used was coated (either with a phenol-formaldehyde-type resin or with a textile-type binder) or not, there was no demonstrable difference in reaction. This biologic “inertness” of fibrous glass dust persisted in spite of an extremely high total exposure—24 months to dust concentrations which averaged somewhat in excess of 100 mg/cu m.