Abstract: At present, the transportation and disposal of used mineral oil is relatively normative compared with the storage process. The storage has certain risk and has been the emphasis and difficulty for used mineral oil management. The exemption limit value (ELV) of used mineral oil storage was set up using environmental risk assessment methodology, which could be used for its exemption management. Based on exposure scenarios of groundwater transport and diffusion and air diffusion, the ELVs for the storage of liquid-phase used mineral oil and oily wastewater sludge were figured out. The results showed that the major pollutants in used mineral oil were volatile organic compounds, e.g. benzene compounds and PAHs, with a few heavy metals. The ELV of oily wastewater sludge storage was too little for exemption management, which indicated that its storage must follow the requests of hazardous waste management. For liquid-phase used mineral oil, the ELV was 487 kg/a based on the exposure scenario of air diffusion in the condition of open container storage.