Objective To investigate the effects of glutathiones-transferase (GST) T1, GSTM1 and epoxide hydrolase (EPHX1) genes on skin injury in workers exposed to coal tar pitch. Methods Workers from a carbon manufacturing company involved in coal tar pitch production and use were selected as the study subjects using a judgment sampling method. Workers with skin injury after exposed to coal tar were selected as the case group (55 cases), and those with the same workshop and type of work but without skin abnormalities were selected as the control group (197 cases). Urine and blood samples were collected from the workers, and levels of polycyclic aromatic hydrocarbon metabolites, including 1-pyrenol (1-OH-P), 1-naphthol (1-OH-N) and 2-naphthol (2-OH-N), in urine were measured using ultra high-performance liquid chromatography tandem mass spectrometry. The GSTT1, GSTM1 and EPHX1 genes in blood were detected by polymerase chain reaction. Results In the case group, all 55 workers reported skin stinging, 25 workers reported itching and flaking, and 15 workers reported blackheads and pigmentation. Urinary levels of 1-OH-N and 2-OH-N were lower in the worker in the case group than that in the control group (all P<0.05). However, there was no significant difference in the level of 1-OH-P between the two groups (P>0.05). There were significant differences in the number of workers with GSTT1, GSTM1 and EPHX1(His139His) genes between the two groups (all P<0.01). The GSTT1 and GSTM1 genes were positively correlated with post-shift urinary levels of 1-OH-N, 1-OH-P, and 2-OH-N (all P<0.01). The EPHX1 (139Arg locus) gene was positively correlated with post-shift 2-OH-N levels (P=0.03). The GSTT1, GSTM1, and EPHX1 (139Arg locus) genes were associated with reduced skin damage among coal tar workers (all P<0.01), after controlling for age, length of service, gender, smoking, and alcohol consumption. Conclusion Exposure to coal tar pitch can cause skin injury in workers, and the GSTT1, GSTM1, and EPHX1 (139Arg locus) genes are protective factors against skin injury in those workers.