Benzene is a hydrocarbon with the molecular formula C6H6. Benzene is a natural constituent of crude oil, and is one of the most elementary petrochemicals. It is a colorless and highly flammable liquid with a sweet smell. It is mainly used as a precursor to heavy chemicals, such as ethylbenzene and cumene, which are produced on a billion kilogram scale. Most non-industrial applications have been limited by benzene's carcinogenicity.
The contamination of water and soil is the worst cause of exposure to benzene. Approximately 100,000 sites in the U.S. have soil or groundwater contaminated with benzene.
Benzene increases the risk of cancer and other illnesses, most notably bone marrow failure. Much clinical, and laboratory data links benzene to leukemia, aplastic anemia, and bone marrow abnormalities. Acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), aplastic anemia, acute lymphoblastic leukemia (ALL), and chronic myeloid leukemia (CML) have been direcly linked to benzene exposure.
In 1948 the American Petroleum Institute stated that "it is generally considered that the only absolutely safe concentration for benzene is zero." and it is classified as a human carcinogen by the US Department of Health and Human Services (DHHS).
In women high levels of benzene exposure for many months caused irregular menstrual periods and decreased the size of their ovaries. In men the likely effect is abnormal amount of chromosomes in their sperm, which can impact fertility and fetal development. Benzene exposure has been linked directly to the neural birth defects spina bifida and anencephaly.
Benzene is widely used in the manufacture of heavy chemicals, plastics, rubber, lubricants, paints, adhesives, resins, pesticides and many other products. Benzene was found in Liquid Wrench, lacquer thinners, flooring adhesives, motor oils, penetrating oils, hydraulic fluids, and many different brands of solvents. Toluene and xylene, commonly used solvents, contain benzene.
The people with the highest risk of developing benzene-related illnesses are industrial workers in positions where the exposure is prolonged and concentrated. Workers at refineries, chemical plants, steel mills, textile plants and print shops have been known to have experienced high benzene exposures. Some industries where benzene exposure could occur include:
Industrial plant Workers (jobs with solvent exposures)
Newspaper Press Workers
Offshore and Oil Workers
Shoe / Leather Workers
Synthetic Rubber Production
Tire Plant Workers
Occupations in refineries or chemical plants could very well involve significant benzene exposure. Coke oven workers or workers in byproduct plants of steel mills may also have been exposed to high concentrations of benzene. Instrument workers, boilermakers, carpenters, insulators, operating engineers, and machinists who worked with benzene or other solvents (such as toluene) may also have had substantial exposures to benzene. Workers on barges hauling gasoline products (up until the mid-1990s when closed vapor systems became required) could also have experienced hazardous benzene exposures.