Interstitial lung disease developed in a 32-yr-old chemist after working 8 yr in a dusty atmosphere containing aluminum powders. Bronchoalveolar lavage disclosed a helper T-lymphocyte alveolitis, and transbronchial lung biopsies showed sarcoidlike epithelioid granulomas. These granulomas contained dust identified by mineralogic analyses as consisting mainly of aluminum particles. Nasal and liver biopsies and a Kveim test did not reveal extrapulmonary granulomatous infiltration. An extensive immunologic work-up showed none of the abnormalities classically seen in sarcoidosis, but peripheral blood lymphocytes exhibited blastic transformation in the presence of soluble aluminum compounds. About 1 yr after cessation of exposure, a chest radiograph and lung function tests remained essentially unchanged, but signs of alveolitis disappeared. This observation suggests that aluminum may cause granulomatous lung disease accompanied by a helper T-lymphocyte alveolitis, similar to that of berylliosis and sarcoidosis. Further observations would be necessary to show if this constitutes an early stage of aluminum-induced fibrosis (aluminum lung).