Next generation sequencing of human cancers have revealed the presence of characteristic mutational signature that reflect their etiology. Furthermore, when a strong strand bias is observed in a mutational signature, it is suggested that DNA adducts might contribute to the mutation induction at the relevant lesions of contextual mutations. These DNA adducts could be considered as “driver adducts” for human cancer development. Therefore, screening and identification of driver adducts that can be linked to the mutational signatures is a promising method to unveil the environmental factors-human cancer relationship. Recently, we have reported unique mutational signatures with C:G to T:A transitions observed in cholangiocarcinoma among printing industry workers in Osaka, Japan. Moreover, we analyzed mutational signatures and driver adducts of 1,2-dichloropropane (DCP) that have been suggested to be responsible for occupational cholangiocarcinomas, by using a multidisciplinary approach, such as whole genome and a comprehensive DNA adducts analyses. Based on the results obtained from the present study, 1,2-DCP might contribute to the occupational carcinogenesis of cholangiocarcinoma.