A safety procedure used to disable machinery and process equipment being serviced by disengaging or isolating it from its power source. This is to ensure that it cannot be restarted until associated maintence is completed. It uses a system of locks and tags in which tags on the locked equipment are used to indicate that the equipment cannot be restarted. The procedure involves notifying employees, shutting down and isolating the equipment, locking and tagging, the release of any stored energy, and verification that the equipment has been isolated.