A blast resistant shelter apparatus (100) includes a framework (201) having at least an upper metal rail. A plurality of metal panels (128) each have a C-shaped cross-section defined by a central flat web (130) and two channel arms (132 and 134) on the opposite sides of the central flat web. The metal panels are vertically mounted within the framework in a side by side relationship to define a wall. Each panel includes an upper (140) and a lower (142) end plate. A metal interior wall cladding (144) is connected to the panels and spans the channel arms of each panel to close the cross-sections of the panels to define an interior space (146). The upper metal rail and the upper end plate of each panel have aligned fill openings defined therethrough for introducing a particulate material (156) such as sand into the interior space of the associated panel.
