What are the concerns about underground hydrogen storage?

Underground storage tanks can be either installed in a vault or directly buried. Both offer additional
protection from external impact and fire, but each has unique challenges. Vaults must be properly
ventilated and designed to not create an explosion or asphyxiation risk. Direct burial vessels should not
have any underground leak points and must be protected from corrosion. Both types of installation must
have hydrogen vents routed to a safe location above grade.