Passive smoking at work: biochemical and biological measures of exposure to environmental tobacco smoke.

Several biochemical and biological measures of tobacco smoke intake were used to evaluate exposure of restaurant personnel to environmental tobacco smoke as compared with active smokers and non-exposed non-smokers. All of the measured parameters--carboxyhaemoglobin (COHb), thiocyanate (SCN) and cotinine in plasma, cotinine and mutagenicity in urine, total white blood cell count (WBC), and sister chromatid exchange (SCE) frequency in cultured lymphocytes--were significantly elevated in the smoker group (n = 22) compared to the non-exposed group (n = 20). Work-related passive exposure (n = 27) was seen most clearly in the cotinine values, both from plasma (mean P-cot in passive smokers 10 ng/ml vs 5.2 ng/ml in non-exposed) and from urine (mean U-cot in passive smokers 56 ng/ml vs 8.3 ng/ml in non-exposed), but significant increases were also seen in the thiocyanate levels (mean P-SNC in passive smokers 58 mumol/l vs 46 mumol/l in non-exposed) and, as a preliminary finding, in total leucocyte count (in passive smokers 8.0 X 10(9)/l vs 6.8 X 10(9)/l in non-exposed). The results demonstrate that environmental tobacco smoke may be an occupational health hazard.