Chronic Exposure
Repeated exposure to high levels of benzene (¡Ü200 ppm) can result in persistent CNS effects. Chronic benzene exposure in the workplace has been associated with hematologic disorders (i.e., thrombocytopenia, aplastic anemia, pancytopenia, and acute myelgenous leukemia). Chronic exposure may be more serious for children because of their potential longer latency period.
Carcinogenicity
The Department of Health and Human Services has determined that benzene is a known human carcinogen. Hematologic neoplasms such as acute myelogenous leukemia have been documented to occur with chronic exposures as low as 10 ppm benzene. Other neoplasms have been documented in animal models.
Reproductive and Developmental Effects
Benzene is not included in Reproductive and Developmental Toxicants, a 1991 report published by the U.S. General Accounting Office (GAO) that lists 30 chemicals of concern because of widely acknowledged reproductive and developmental consequences. However, it has been shown to cross the placenta in humans and to be fetotoxic in animals. No information was located as to the presence of benzene in breast milk or of the potential transfer to nursing infants.
Benzene has very weak genotoxicity, Nonetheless, special consideration regarding the exposure of pregnant women is warranted. Medical counseling is recommended for the acutely exposed pregnant woman