BACKGROUND Sarcoidosis is a granulomatous disorder of unknown cause that usually first involves the lungs. After the diagnosis of a deck grinder was changed from sarcoidosis to dust-induced lung disease by the VA, the Navy asked the National Institute for Occupational Safety and Health (NIOSH) to determine if Navy work environments have been associated with lung diseases, some of which may have been reported as "sarcoidosis." METHODS Sarcoidosis-related associations were measured using a case-control approach involving the modern personnel database of the Naval Health Research Center (NHRC). Sarcoidosis incidence rates were also computed using total Navy manpower data, and previously published military data from the 1940s and 1950s were juxtaposed with current findings to gain a broader historical perspective. RESULTS When reported sarcoidosis incidence rates from 1943 to 1993 are examined, an unexplained peak of military sarcoidosis rates appears in the 1960s and 1970s along with a decline in the black/white ratio of these rates from about 17:1 to 6:1. The case-control analyses reveal a decreased risk for sarcoidosis diagnoses among men who worked only on "clean ships." CONCLUSIONS These findings suggest that sarcoidosis-like diseases in the military may be associated with environmental factors. To implement effective primary prevention, early detection, and treatment programs for sarcoidosis-like disease, these trends and work environment patterns need to be explained. Clinical studies of Vietnam-War-era veterans, which assess their work exposures and job activities in more detail, may identify preventable causes among this generation, which has a historically high rate of disease.