A credentials verification system for controlling compliance with required carrying of permit cards at construction work sites has an association database with stored data that correlates work permits with RFID data corresponding to RFID tags, where a respective and unique RFID tag is assigned to and irremovably attached to each work permit. A local control system at each work site includes: an RFID tag reader that reads an RFID tag wirelessly when a worker approaches within a predetermined distance of the RFID tag reader; a local processor and a software facility associated with the local processor that verify that a sensed RFID tag is authorized; and an entry controller operating under the local processor for controlling the entranceway into the work site so as to admit a worker only when the worker has been determined to carry the required work permit(s).