A safety procedure used to ensure dangerous machines are shut off and cannot be restarted during maintenance is called what?

• A. Lockout Procedure
• B. Tagout Security
• C. Safety Interlock System
• D. Lockout-tagout (LOTO)

Answer: (D)

Isolating dangerous energy during maintenance is done with a procedure that both physically blocks the energy source and clearly communicates that work is underway. This is Lockout-Tagout. The lock provides a physical barrier—placing a padlock or other locking device on the energy-isolating device so it cannot be opened or energized. The tag adds essential information: who placed the control, what work is being done, and when it should be removed. Together, they prevent accidental restart and ensure that only the person who applied the lock can remove it, which is crucial for maintaining a safe environment when equipment could be hazardous.

In practice, you would shut off the machine’s energy source, apply the locking device, and attach a tag with your identification and purpose. Only after the work is completed and the area is verified safe can the lock be removed and the equipment reenergized. The combination of a lock and a tag is what makes this approach reliable and enforceable.

Other terms describe parts of the idea or focus on a single aspect. A lockout procedure covers the process of locking out, but without the tagging element, it relies on people to enforce it, which is less robust. A safety interlock system refers to a device that prevents starting if a guard or safety condition isn’t met, not the broader practice of controlling hazardous energy during maintenance. Tagout security isn’t a standard term for this safety practice. The comprehensive method that covers both isolation and clear warning is Lockout-Tagout.