A safety study of gaseous hydrogen supply stations with 40MPa storage system is undertaken through a riskbased approach. Accident scenarios are identified based on a generic model of hydrogen station. And risks ofidentified accident scenarios are estimated and evaluated comparing with risk acceptance criteria. Also,safety measures for risk reduction are discussed. Especially for clearance distance, it is proposed that thedistance from high-pressurized equipment to site borders should be at least 6 meters. As a result of the study,it is concluded that risks of accidental scenarios can be mitigated to acceptable level under the proposedsafety measures, with several exceptions. These exceptional scenarios are very unlikely to occur, butexpected to have extremely severe consequence once occurred.