The hydrogen seasonal storage, as pure gas or mixture with natural gas, is expected to sustain both the energy storage and sectorial integration. The salt caverns are able to store the large quantities of hydrogen at elevated pressures for seasonal period of time. In this study, a new approach integrating Additive Ratio ASsessment (ARAS) method and interval type-2 hesitant fuzzy sets (IT2HFSs) is proposed to tackle the underground hydrogen storage site selection problem in Romania. This study presents an integrated method to select the best location among four alternative sites based on 7 main and 14 sub-criteria. The result shows that the proposed method can be useful to handle fuzzy multi criteria decision-making (MCDM) problems.