Bung plug closure for bung-hole containers

A bung plug closure for bung-hole containers, the bung plug closure comprising a bung plug (10) for being placed in a bung neck (24) of the bung-hole container and a seal cap (11) for closing a plug recess (13) formed in the bung plug (10), the plug recess (13) having a receiving space (19) for receiving a dimensionally elastic engaging body (20) which is formed on the seal cap (11) and which is provided with a radial locking protrusion (21), and the bung plug (10) having key projections (15), which are spaced apart from each other by gaps (16), are disposed on an interior wall (14) of the plug recess (13) and whose inner surfaces (18) define the receiving space (19), matching locking elements (32) for interlocking with the locking protrusion (21) of the engaging body (20) being provided in the plug recess (10) and protruding radially inward over the locking protrusion (21) of the engaging body (20) after interlocking, a valve (49) being disposed in a bottom (44) of the plug recess (13), said valve (49) having a valve body (50) which is disposed in a valve opening (51) of a bottom recess (45), said valve body (50) being provided with a valve cover (55, 60) which is connected to the bung plug (10) and which is provided with a vent (58, 64), characterized in that the valve cover (55, 60) is an elastically deformable disk whose diameter (d) is smaller than a diameter (D) of the receiving space (19), the valve cover (55, 60) being connected to the bung plug (10) in such a manner that a circumferential edge (56, 65) of the valve cover (55, 60), which protrudes radially outward over the matching locking elements (32), is received between the locking protrusion (21) of the engaging body (20) and a recess edge (43) of the bottom recess (45).