This study investigates the impact of exposure to heavy metals on the health of workers in the petroleum industry. In this study forty participants in four groups were involved. Group 1 was the control, while groups two, three and four were samples collected from mechanic workers, filling station attendance and artisan petroleum handlers respectively. Blood samples were collected and analyzed for heavy metals, immunological parameters and liver function parameters. The results revealed that the concentration of the various heavy metals was highest in artisan petroleum handlers, followed by mechanic workers and filling station attendants. The heavy metal concentration was significantly lowest in the control group. Also from the result, the immunological parameter was highest in artisan petroleum workers followed by the mechanic workers and filling station attendance. The control group has the lowest level of immunoglobulin level. The result further revealed that the level of liver enzymes was significantly low in control group followed by the filling station attendants, the mechanic workers and finally the artisan petroleum handlers respectively.