Utility of a routine medical surveillance program with benzene exposed workers.

BACKGROUND

A medical surveillance program of benzene-exposed workers has to be established in such a way as to observe early signs of benzene-induced cytopenia, pancytopenia, or leukemia. This study evaluates the utility of routine medical survey applied to benzene-exposed workers by analyzing the hematological, immunological, and cytogenetic assay results.

METHODS

The results of a previous study of hematological, immunological, and cytogenetic assays in benzene-exposed workers (up to 15 ppm) are used to discuss medical surveillance program by defining the relationship between various benzene exposure concentrations and toxic endpoints.

RESULTS

Exposure to benzene concentration lower than 5 ppm does not produce any abnormal hematological measurements. For benzene cumulative exposure above 100 (ppm-years), some blood indices [mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), band neutrophils] show significant differences in comparison to the control group. The incidence of dicentric chromosomes was higher and the level of B-lymphocytes was lower even with workers exposed to 5 ppm of benzene; correlation with exposure indicators was not found.

CONCLUSIONS

The results suggest that peripheral blood indices, although not sensitive enough, are still the most suitable parameters in a health surveillance program applied to benzene-exposed workers. B-lymphocytes could be a promising indicator of the benzene-induced damage. Cytogenetic tests did not prove to be suitable. Further investigation of useful screening tests for health surveillance program of benzene-exposed workers is still required.