What is Lockout-Tagout?

Lockout-Tagout (LOTO) is a safety procedure that isolates hazardous energy sources — electrical, mechanical, hydraulic, pneumatic, chemical, or thermal — before workers service or maintain equipment. A physical lock ("lockout") physically prevents a machine from being energized, and a tag ("tagout") labels the isolation point to warn others not to restore power.

Why LOTO matters

Machines that unexpectedly start up or release stored energy during maintenance are a leading cause of serious workplace injuries. LOTO procedures are designed to prevent this by ensuring energy sources are verified as isolated before anyone works on the equipment.

Basic steps in a LOTO procedure

  1. Prepare — identify all energy sources for the equipment
  2. Shut down — power down the equipment using normal operating procedures
  3. Isolate — disconnect or block all energy sources
  4. Lock and tag — apply a lock and warning tag to each isolation point
  5. Verify — confirm the equipment cannot be restarted before work begins

References