The determination of toxic metals in urine is an important clinical screening procedure. In this study, differential-pulse anodic stripping voltammetry on a hanging mercury drop electrode was used for the simultaneous determinations of zinc, cadmium, lead and copper in the urine of 23 production and 23 quality control workers in a steel production plant and their matched normal controls. The urine specimens were pre-treated with a mixed acid solution and Analytical Products Group set-point laboratory standards were used to check the analytical accuracy. The results indicated that the urinary zinc, cadmium, lead and copper levels of the production and quality control workers are significantly higher than those of the controls. The possible connection of these elements with the etiology of disease is discussed. The results also show the need for immediate improvements in workplace ventilation and industrial hygiene practices.