Hygienic characteristics of carbon black used in tyre production.

Seven types of carbon black used in type production were subjected to hygienic evaluation. The coal tar pitch volatiles (CTPVs), toluene solubles, were determined by the gravimetric method and benzo/a/pyrene by HPLC with a spectrophotometric detector. Toluene solubles were found to amount to 0.12-0.25% (by weight). Benzo/a/pyrene (1.44-3.07 ppm) was detected in five out of the seven carbon blacks examined.