Chronic beryllium disease (CBD) is typically considered only when occupational exposure to beryllium is a certainty; however, CBD has also occurred in occupational and environmental settings where exposure was unexpected. When the etiology of a case of granulomatous pulmonary disease is not determined, sarcoidosis is the "diagnosis of exclusion." This diagnosis does not communicate much information about the patient's prognosis, the disease's etiology, or even what disease etiologies were specifically excluded. Some cases of CBD have been called sarcoidosis, allowing exposure to continue for the patient and (at times) other individuals. The granulomatous changes of sarcoidosis are thought to result from an abnormal immune response. While the etiologic agents that can initiate this response are largely unknown, the immunopathogenesis of CBD has been well described, and laboratory methods are available in a few centers that can (if used) identify beryllium hypersensitivity. The potential for exposure and disease to be widely separated in time and location makes it important for health-care and environmental health professionals to be aware of these new diagnostic methods.