1. Benzene Metabolites: Phenol, catechol, and hydroquinone are metabolites indicating exposure to benzene, a known carcinogen. 2. Aflatoxin Metabolites: Aflatoxin M1 and M2 are metabolites of aflatoxin B1, a potent liver carcinogen. 3. Cotinine: A metabolite of nicotine, used as a biomarker for tobacco smoke exposure.