[Evaluation of occupational benzidine exposure of workers in automated benzidine plants]

The exposure to benzidine under old production conditions, during start-up and at normal work in the new benzidine production division in one of the plants in Poland was compared. In comparison with the old production conditions, in the automatized production process airborne benzidine concentrations were 10-fold lower so that the geometric mean of benzidine concentrations was 0.0008 mg/m3. The approximate annual dose of absorbed benzidine amounted to 0.065 mg, as estimated from urinary benzidine concentrations, and was three times lower than the one found in the old productive conditions, i.e. 0.2 mg. The benzidine absorption in the respiratory system was approx. 10%, the remaining part of the dose was probably absorbed by skin. This was proved by high concentrations of benzidine on the skin (epigastrium-up up to 300 micrograms/dcm2, palm-up to 680 micrograms/dcm2), and objects (up to 400 micrograms/dcm2). The results indicate a need to maintain the hygienic regime, introduced in the old productive conditions, including the establishment of the age up to which workers older than 50 may be employed. The cleanness in all the premises should be improved.