Abstract
The average concentration of coproporphyrin in the urine of groups of workers exposed to different concentrations of lead in air increased with the average concentration of lead to which they were exposed. However, the correlation between atmospheric lead and coproporphyrin levels In urine did not appear to follow any simple curvilinear relationship, particularly for workers exposed to excessively high concentrations. No significant relationship was observed between the concentration of urinary coproporphyrin and periods of exposure. It is concluded that, only when the measurement of lead in blood cannot be obtained, the use of the relatively simple determination of coproporphyrin in urine and lead in air, together, but not separately, may provide the basis for reasonable hygienic control in the lead trades, if accompanied by the appropriate medical supervision.