Occupational exposure of non-smoking restaurant personnel to environmental tobacco smoke in Finland. 
Environmental tobacco smoke (ETS) exposure levels in different restaurant types in Finland were assessed before the National Tobacco Act restricting smoking in restaurants was activated.  Exposure to ETS was determined by measuring nicotine in the breathing zone of non-smoking restaurant workers and by quantification of the nicotine metabolites cotinine and 3-hydroxycotinine in the urine of these workers during one whole work week.  Altogether 23 workers from 15 restaurants were included in the study.  The geometric mean (GM) breathing-zone nicotine level was 3.9 microg/m(3) (3.7 microg/m(3) in pubs, 1.4 microg/m(3) in dining restaurants, and 10.2 microg/m(3) in nightclubs).  The GM cotinine and trans-3'-hydroxycotinine level in urine were 3.3 ng/mg((creatinine)) and 15.3 ng/mg((creatinine)), respectively.  The exposure to ETS of restaurant workers in dining restaurants was clearly lower than that of workers in pubs and nightclubs as indicated by all ETS-markers used in the present study.  During the work week, the cotinine and 3'-hydroxycotinine levels in urine of the study subjects increased.  The correlation between breathing zone nicotine and urine cotinine and hydroxycotinine was 0.66 for both compounds.  Post-shift cotinine and hydroxycotinine levels were not significantly higher than the pre-shift levels.  If 9 ng cotinine/mg((creatinine)) is considered as the level above which heavy exposure has occurred, then this level was exceeded by 14 (approximately 60%) subjects at least once during the work week.  Nicotine metabolite concentrations in the urine increased during the work week in 80% of the subjects, and the increase was especially noticeable for subjects working in both pubs and nightclubs.  The study indicates that measures to restrict ETS exposure in restaurants are needed.