Lockout/Tagout is a safety procedure are used to ensure that machines are properly shut off and made incapable of restarting prior to the completion of maintenance or service work. "Lock and tag" works in conjunction with a locking device or the power source with the hasp, and placing it in such a position that no hazardous power sources can be positively engaged. The procedure requires that a tag be affixed to the locked device indicating that it is not to be turned on.

Most industrial accidents are caused by the uncontrolled release of hazardous energy. Many of these accidents can be prevented by proper lockout/tagout procedures. Lockout/Tagout is designed to prevent needless deaths and serious injuries to service and maintenance workers by controlling hazardous energy.

To perform service and maintenance work on industrial equipment safely, it is necessary to understand the importance of energy control and established lockout/tagout methods.