Benzene is an organic compound consisting of carbon and hydrogen that is a colorless liquid at room temperature, is highly flammable, and has a distinctive sweet smell similar to that of gasoline (which contains benzene). It is is also highly toxic, targeting the lungs, liver, kidneys, heart and brain, can damage DNA and chromosomes, and is carcinogenic. It can be ingested by inhaling, skin contact, or drinking contaminated water.
Benzene is produced naturally by forest fires and volcanoes. But it is also produced synthetically on a vast scale, now mainly from petroleum, as a precursor in the production of chemicals with more complex structures, particularly polystyrene, as well as other plastics, detergents, lubricants, medications, dyes and pesticides.
Major sources of human exposure include tobacco smoke, gasoline, exhaust from motor vehicles, exhaust from gas stoves, and industrial emissions. Despite its limited use in consumer products because of its toxicity, indoor air nevertheless typically contains higher levels of benzene than outdoor air because of emissions from the diverse household chemical products that contain it such as glues (e.g., used in furniture, cabinets and carpeting), paints, furniture wax, and even some detergents.