Toluene in blood after exposure to toluene.

Analysis of the postshift toluene levels in the blood of 50 assembly line workers indicates that toluene levels in blood were correlated with the time-weighted average (TWA) exposure levels of the same day (r = 0.90). Toluene concentrations in 10 laboratory technicians not exposed to toluene at their work gave an average level of 0.002 microgram/mL of blood. Significant levels of residual toluene were found in the preshift blood of workers exposed to 57 to 146 ppm of toluene as compared to the unexposed. The blood toluene values determined from capillary blood taken from finger tips are higher than the reported values from venous blood. The method described is useful for large-scale screening and epidemiological surveys.