In-ground storage tanks have a high level of safety and are environmentally friendly. The side wall and bottom slab of in-ground storage tanks have a multiplex structure with three layers: reinforced concrete, insulation and a membrane. In-ground LNG storage tanks are only partially visible from the outside of the terminal site making them difficult to be targeted by terrorists. Furthermore, since the LNG is stored below the ground surface, in the unlikely event of a terrorist attack or the concrete roof being destroyed by a projectile, the LNG would not leak onto the ground. In-ground storage tanks do not need to be surrounded by a dike and the legally required space between tanks as well as the necessary distance from items to be protected is relatively small allowing the tanks to conserve space