Approximately 173 subjects employed as waiters, waitresses, or bartenders in the Knoxville, TN, Standard Metropolitan Statistical Area collected a sample of air from their breathing zone while at their workplace for one shift. In addition, area samples were placed near the work spaces of many of the subjects. Collected samples were analyzed for respirable suspended particulate matter (RSPM), ultraviolet-absorbing and fluorescing particulate matter, solanesol, 3-ethenyl pyridine (3-EP), and nicotine. Saliva samples were collected from the subjects prior to and within 24 h following their work shift, to confirm their non-smoking status. The range of concentrations of environmental tobacco smoke (ETS) constituents encountered was considerable, e.g., for nicotine, from undetectable to more than 100 microg/m3. However, the highest RSP levels observed were considerably lower than OSHA workplace standards. Distributions of ETS concentrations suggest that there are two "ETS exposure" types of bartenders: those that work in single room bars and those that work in larger, multiroom restaurant/bars. Personal exposure to ETS of the former group was ca. 10x greater than those of the latter group, who were exposed to ETS levels more comparable to those encountered by wait staff. Exposure (concentration x duration) differences between wait staff and workers in other types of unrestricted smoking environments reported in other studies suggest that exposures in the restaurant environment may be more difficult to assess than originally considered. Salivary cotinine levels indicated that for those subjects living in smoking homes, ETS exposures outside the workplace are at least as important as those in the workplace.