Benzene is a colorless, flammable chemical with a sweet odor that is liquid at normal temperatures. It is part of a family of chemicals commonly referred to as volatile organic compounds (VOCs), because they evaporate quickly when exposed to air. Although benzene can be formed and emitted from natural processes, exposure to it comes mostly from human activities.

Benzene is among the 20 most widely used chemicals in the United States. It is used as an industrial chemical in the production of products including plastics, resins, synthetic fibers, rubber lubricants, dyes, detergents, drugs, and pesticides. Benzene is also naturally found in crude oil and is a major part of gasoline.

Human exposure to benzene in the environment usually takes the form of gasoline fumes, automobile exhaust, emissions from certain factories, and off-gassing from some commonly used products. Areas with heavy vehicle traffic can have dangerous levels of benzene in the air. Benzene can also off-gas from paints and glues and become concentrated in an indoor environment. Additionally, cigarette smoking and secondhand smoke can account for significant benzene exposure. Finally, industries such as oil and gas can contribute to local benzene pollution greatly.

The health effects of exposure to benzene include irritation of the body parts in contact with the chemical, immune system problems, and nervous system conditions. Symptoms of short-term exposure to benzene include skin, eye, and respiratory tract irritation. Prolonged exposures to even low concentrations of benzene can result in nervous system dysfunction  and heart problems, as well as trigger anemia and compromise the immune system. Finally, it has been long established that benzene exposure can cause many forms of leukemia. The International Agency for Cancer Research, US Environmental Protection Agency, and US Department of Health and Human Services have all classified benzene as causing cancer in humans.  The usefulness of benzene in the production of industrial and consumer products should not supersede the serious dangers of exposure to this harmful chemical.