Benzene

Benzene Exposure?
Benzene exposures likely occur among worker who are in close contact with chemical and its products.

Benzene can enter the environment through spills, accidental releases of chemicals, volcanic eruptions, and forest fires.

With exposure from less than five years to more than 30 years, people have either developed or died from leukemia.

What is Leukemia?
Leukemia is a cancer of blood-forming tissue such as bone marrow. The types of leukemia are grouped by the type of cell affected and the rate of cell growth. It can be either acute or chronic.

All the cancers begin in cells, which are the building blocks for blood and other tissues. Normally, cells grow and divide to build new cells, as the body needs them. As and when cells grow old, they die and new cells take their place.

Sometimes this process goes wrong and new cells form when the body does not need them, and old cells do not die. Leukemia is cancer that begins in blood cells.

In people with leukemia, the bone marrow produces abnormal white blood cells and the abnormal cells are leukemia cells.

The four main types of leukemia are as follows:

• Acute myelogenous leukemia (AML)
• Acute lymphocytic leukemia (ALL)
• Chronic myelogenous leukemia (CML)
• Chronic lymphocytic leukemia (CLL)
• Hairy cell leukemia (HCL)

Other possible diseases linked to benzene:

• Myelofibrosis
• Polycythemia vera
• Cytopenias
• Multiple myeloma
• Hodgkin's disease
• Pancytopeni

Benzene and Science
The results of a new study suggest that even low levels of exposure to the chemical benzene have measurable adverse health effects. Researches in Science report that Chinese factory workers breathing benzene at levels permissible by U.S. standards have fewer white blood cells and platelets than unexposed workers do.

Experts have known for years that high levels of benzene reduce white blood cell counts and cause leukemia in people. Benzene is found in gasoline and tobacco and is used in many chemical-manufacturing processes.

To look for effects of such low-level exposures, scientists from institutions including the National Cancer Institute (NCI), the University of California at Berkeley and the Chinese Center for Disease Control and Prevention teamed up to assess 250 shoe factory workers in China, who are routinely exposed to various levels of benzene. By carefully measuring individual laborers' exposure to benzene and other chemicals, the researchers showed that the 109 workers exposed below the 1 ppm level still had white blood cell counts almost 15 percent lower than similar workers who were not exposed. The reduction was larger for individuals subjected to more than 10 ppm of benzene.