Metabolites of a tobacco-specific lung carcinogen in nonsmoking casino patrons.

Epidemiologic data have shown increased risks of lung cancer in nonsmokers exposed to environmental tobacco smoke (ETS). We measured biomarkers in urine samples from nonsmokers before and after a 4-h visit to a casino where smoking is allowed. The tobacco-specific lung carcinogen, NNK [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone] is a constituent of ETS.