A verification system is implemented to ensure the continued isolation and de-energization of hazardous energy sources during the course of maintenance and servicing operations. Once the equipment is shut down and the hazardous energy has been controlled, maintenance/servicing personnel, sometimes in conjunction with operations personnel, must test the machinery or equipment to verify that the isolation of the equipment’s energy source(s) is effective. The employees may walk through the affected work area to verify isolation. If there is a potential for releasing or re-accumulating hazardous energy, verification of isolation must be continued.