<p>The petrochemical industry is one of the main anthropogenic sources arsenic exposure. However, there is a lack of studies focusing on inorganic arsenic species and their impact on metabolites. Therefore, the purpose of this study was to investigate the exposure of arsenic species in the urine of residents living near a petrochemical industrial area in central Taiwan to determine whether it is associated with changes in metabolites. We recruited 81 children and 79 elderly residents living near a petrochemical complex in central Taiwan. Study subjects completed questionnaire survey and urine sample were collected to detect four arsenic species by HPLC–ICPMS and metabolites by GCxGC-TOFMS. Compared to the low exposure group, the children had significantly higher concentrations of all arsenic species, while the elderly had only significantly higher concentrations of inorganic arsenic in high exposure group. Specifically, children in the high-exposure area showed about 20-fold higher As³⁺ and tenfold higher As⁵⁺ concentrations, whereas elderly participants had 1.4-fold higher total arsenic levels. Moreover, high exposure groups performed significantly worse on various arsenic methylation indicators, especially in children. Further, we identified down-regulation of several inorganic arsenic-related methylation pathway metabolites and also found up-regulation of some metabolites of oxidative stress caused related to inorganic arsenic. We concluded that petrochemical industry may contribute to higher inorganic arsenic exposure related to worse arsenic detoxification ability and higher oxidative stress to residents nearby.</p> Graphical abstract <p></p>