What is Benzene?

Benzene is a colorless or yellow liquid at room temperature. It is highly flammable, dissolves slightly in water, has a sweet odor, and evaporates into the air very quickly.

Benzene is formed through both natural processes and human activities. Natural sources of benzene include volcanoes and forest fires. Benzene is also a natural part of crude oil, gasoline, and tobacco smoke. Benzene can be released into the air through emissions from motor vehicle exhaust, burning coal and oil, and at gasoline service stations. It is used in manufacturing a wide range of industrial applications, including production of other chemicals, dyes, detergents, and some plastics.

The U.S. Department of Health and Hyman Services (DHHS), along with the International Agency for Research on Cancer (IARC), and the U.S. Environmental Protection Agency (EPA) have determined that benzene is cancer-causing (i.e., a carcinogen), and therefore, of public concern.

How Does Benzene Exposure Occur?

If inadequately protected by safety equipment and other precautionary measures, individuals who work in industries that manufacture or use benzene may be exposed to high levels of benzene. Low levels of benzene also exist in the air due to emissions from tobacco smoke, gasoline service stations, motor vehicle exhaust, waste sites, and other industrial emissions. Indoor air may contain even higher levels due to the presence of products such as glues, paints, furniture wax, and detergents. Additionally, benzene leaks from underground storage tanks or hazardous waste sites may contaminate well water.

Benzene's presence in the human body can be detected by measuring levels in the breath, blood, or the breakdown products found in urine. However, these measurements are not helpful in determining low levels of benzene. Breath and blood tests must be performed shortly after exposure. Benzene converts to products called metabolites, certain kinds of which can be measured in urine. Once again, urine tests must be done shortly after exposure and may not be a reliable indicator of benzene exposure, since metabolites may be present due to other sources.