Toluene, also known as methylbenzene, is a colorless liquid with a sweet, pungent odor. It is mainly used as a raw chemical for industrial purposes and as a solvent, but it may also be found in consumer products such as paints, glues and nail polish removers. Toluene, like benzene, also occurs naturally in crude oil. Exposure to toluene can cause skin irritation, drowsiness or dizziness, damage to the central nervous system, and is also suspected of damaging the unborn child. Exposure to toluene can be determined by analyzing the urinary excretion of S-benzyl-N-acetylcysteine (S-BMA), a widely used biomarker of toluene exposure.