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.

FDA Study - Benzene in Soft Drinks

Recently, the U.S. Food and Drug Administration (FDA) conducted studies on soft drinks and other beverages to determine benzene levels in these products. Soft drinks and other beverages may contain benzoate salts (such as sodium benzoate or potassium benzoate), which act as a preservative that inhibits the growth of bacteria, yeasts, and molds. Beverages may also contain Vitamin C (ascorbic acid) to prevent spoilage or to provide additional nutrients. Under certain light and heat conditions, benzoate salts can react with ascorbic acid to form benzene.

Since the U.S. Food and Drug Administration (FDA) has no regulatory limits for benzene in beverages other than bottled water, it uses the standard set by the EPA, which is 5 parts benzene per billion parts of water (ppb) as the maximum allowable level of benzene in drinking water.

A 2005-2006 survey by the FDA and Center for Food Safety and Applied Nutrition (CFSAN) shows that most soft drinks and other beverages to date do not pose a safety concern, since the benzene levels found in those products are either negligible or below 5 ppb. However, while the FDA believes that the beverage industry has taken appropriate steps to reduce benzene levels, it continues to follow-up with companies who produce beverages that exhibited high benzene levels according to this latest survey.

Short-Term and Long-Term Effects of Exposure to Benzene

Breathing high levels of benzene can lead to signs and symptoms which manifest themselves within minutes to several hours. These symptoms include:

• drowsiness
• dizziness
• rapid or irregular heartbeat
• headaches
• tremors
• confusion
• unconsciousness
• death (if exposed to very high levels)

Consuming food and beverages with high levels of benzene can also result in symptoms within minutes to several hours including:

• vomiting
• stomach irritation
• dizziness
• drowsiness
• convulsions
• rapid or irregular heartbeat

Benzene is also an eye, skin, and respiratory tract irritant.

Long-term (chronic) exposure to benzene may cause blood disorders, leukemia, or have negative effects on the female reproductive system. Blood disorders that result from long-term benzene exposure may affect bone marrow (the tissues that produce blood cells), which can lead to anemia. Long-term exposure may also cause excessive bleeding, as well as damage to the immune system due to changes in the levels of antibodies and the loss of white blood cells.

Long-term exposure to high levels of benzene in the air can cause leukemia, particularly Acute Myelogenous Leukemia (AML).