A health risk assessment for the Lin-Yuan Petrochemical Industrial Complex (LYPIC) in southern Taiwan was conducted in this study. The main aims of the study were to develop an emission inventory for the 21 processing plants in the LYPIC, conduct hazard identification based on the emission inventory, perform an exposure assessment by applying air dispersion modeling to obtain the annual average concentration of hazardous air pollutants near the LYPIC, and estimate the lifetime risk of cancer associated with volatile organic compound exposure for residents living in the vicinity of the LYPIC. Comparing with the reported monitoring data from several petrochemical and refinery plants in the world, the estimated exposure concentrations in this study were within reasonable range. The results of cancer risk assessment showed that the cumulative excess lifetime cancer risk (ELCR) at four representative residential sites surrounding the LYPIC were in the range of 9.3 × 10–5 to 1.7 × 10–4. From a risk management perspective, in order to protect human health, greater emphasis on the reduction of emissions of benzene, 1,3-butadiene, acrylonitrile, and vinyl chloride is recommended. This study provides a feasible risk assessment procedure to identify the key carcinogenic chemicals emitted from a petrochemical industrial complex.