A lid (2) for a closed container incorporates an opening which can be closed by a door (5) provided with side walls (18) so that even when the door is open, the only access to the interior of the container is through a slot (8) in a wall (7) of the door unit. Needles or other sharps may be introduced through the opening (8) into the container for safe storage. When the door (5) is pushed down to close the opening, a two-part live hinge formed by grooves (14) acts to bias the door into the closed position. Re-opening is achieved by pressing on the flange (6) incorporating the grooves (14). A flap (21) provides a secondary closure device.