Abstract: A system is provided for safe passage of personnel between a pair of protective enclosures, at least one of which is portable such as a garment or a mobile unit, and which afford a protective environment to persons or things therewithin. The enclosures comprise an eveloping structure having at least one flexible panel, and the enclosures are adapted to be brought into a position with panels abutting. A first opening is formed in one of said panels and a second opening in the other panel, the openings being dimensioned and arranged to be co-extensive when said panels are in abutting position, and primary fasteners, such as zippers, are attached to each of the openings for repeated opening and closing thereof. Secondary covering fasteners, including flaps with fabric hook-latch material, are on the exterior of each of the panels surrounding and totally covering the primary fasteners.