Abstract: A mobile safety structure for the storing and handling of containers of hrdous materials comprising multiple modular storage units. The modular storage units may be configured in tandem to form one embodiment of the modular mobile safety structure. In this configuration access between the interiors of adjacent modular storage units is provided by a bellows which is connected to and removable from a bellows support frame in a side wall of each modular storage unit. The modular storage units may also be configured in a stacked arrangement to form an alternate embodiment of the modular mobile safety structure. In this configuration access between the interiors of the stacked modular storage units is provided through an opening between units in the stack. A pull down safety ladder affixed to the roof assembly of all units except the top unit in the stack allows the user to gain access to each unit in the stack of modular storage units.