Benzene
Benzene: A sweet smelling, highly toxic hydrocarbon. Long-term exposure to benzene is known to cause anemia and leukemia. The anemia associated with benzene exposure is termed aplastic anemia. The types of leukemia associated with benzene exposure are adult acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL). It is thought that benzene induces DNA damage in hematopoietic stem cells that give rise to leukemic clones of cells.
Breathing benzene can cause drowsiness, dizziness, tachycardia (rapid heart rate), headache, tremors, confusion, unconsciousness, and death. Eating or drinking foods containing high levels of benzene can cause vomiting, irritation of the stomach, dizziness, sleepiness, convulsions, rapid heart rate, and death.
Benzene is widely used as a solvent. It comes from light coal tar oil and chemically is C6H6. It is a colorless liquid that evaporates into the air very quickly and dissolves slightly in water. Some industries use benzene to make other chemicals which are used to make plastics, resins, and nylon and synthetic fibers. Benzene is also used to make some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides. Natural sources of benzene include volcanoes and forest fires. Benzene is also a natural part of crude oil, gasoline, and cigarette smoke.
The use of glues and other products containing benzene has stopped in most developed countries because of its danger and the allowable worker exposures to the chemical have been drastically reduced. In some countries such as China, however, the use of benzene-containing glues reportedly persists in thousands of small factories.
The US Environmental Protection Agency (EPA) has set the maximum permissible level of benzene in drinking water at 0.005 milligrams per liter (0.005 mg/L). The EPA requires that spills or accidental releases into the environment of 10 pounds or more of benzene be reported to the EPA. The US Occupational Safety and Health Administration (OSHA) has set a permissible exposure limit of 1 part of benzene per million parts of air (1 ppm) in the workplace during an 8-hour workday, 40-hour workweek.
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