Benzene is an organic chemical, one of the aromatic hydrocarbons. It is essentially colorless and has a slightly sweet odor. It is highly flammable. It dissolves easily in water and evaporates quickly at room temperature. It boils at 176 degrees F.

Natural sources of benzene include volcanoes and forest fires. Benzene is also a natural part of crude oil, gasoline and cigarette smoke. Some industries use benzene to make other chemicals that are used to make plastics, resins, nylon and synthetic fibers. Benzene is also used to make some types of lubricants and pesticides. Benzene can cause cells not to work correctly, leading to conditions such as anemia. It can damage the immune system by changing blood levels of antibodies and causing the loss of white blood cells.

An ingredient of gasoline, benzene is found in groundwater contaminated by leaking underground fuel storage tanks, or in surface water subject to fuel spills. Gasoline contains a bit less than 1% benzene. Produced from coal or petroleum (usually the latter), Benzene ranks among the top 20 chemicals in production volume. Used to make solvents, detergents, plastics, resins, paint and many other products.

Tobacco smoke contains benzene as does burning PVC.

Benzene is a carinogen in humans, plus long exposure to high levels in air causes leukemia. People who are exposed over long periods in their workplace are most at risk.

Drinking water or eating food containing high levels of benzene can cause, vomiting, dizziness, or even death.

The EPA regulates benzene. The MCL for benzene in water is 0.005 mg/L (5 ppb).
Water treatment: Benzene can be removed by adsorption with granular activated carbon. It can also be treated by ozonation.

Sources: US EPA, US Occupational Safety and Health Administration, US Centers for Disease Control and Prevention, Clean Water Partners. Water Technology Volume 32, Issue 4 - April 2009