Chronic granulomatous lung disease caused by industrial exposure to beryllium continues to occur, but no community cases have been reported in more than 30 yr. With the advent of a blood screening test that detects beryllium sensitization, physicians can discriminate chronic beryllium disease from sarcoidosis. A 56-yr-old woman in whom sarcoidosis was diagnosed had an unremarkable occupational history, but her husband was a beryllium production worker. Blood and bronchoalveolar lavage lymphocyte transformation tests, measuring the beryllium-specific cellular immune response, were abnormal, confirming a diagnosis of chronic beryllium disease. Chronic beryllium disease continues to occur in the nonoccupational setting and among bystanders in industry, masquerading as sarcoidosis. Because even transient or possibly low levels of exposure may cause disease, this case has important implications for how clinicians, industry, and government agencies define the populations at risk of chronic beryllium disease.