This study investigates the health impact of prolonged exposure to heavy metals on workers in the petroleum industry. Forty participants were grouped into four categories: control, mechanic workers, filling station attendants, and artisan petroleum handlers. Blood samples were analyzed for the presence of heavy metals, immunological parameters, and liver function markers. The results showed that the highest concentrations of heavy metals were found in artisan petroleum handlers, followed by mechanic workers and filling station attendants, with the lowest levels observed in the control group. In terms of immune function, artisan petroleum workers exhibited the highest levels of immunoglobulins, while the control group displayed the lowest. Liver enzyme levels were significantly lower in the control group and progressively higher in the filling station attendants, mechanic workers, and artisan petroleum handlers. These findings highlight the potential risks posed by heavy metal exposure in the petroleum industry, particularly in terms of immunotoxicity and hepatotoxicity. The results underscore the need for improved health and safety regulations to protect workers from the detrimental effects of heavy metal accumulation.