What is the primary purpose of lockout/tagout (LOTO) in occupational hygiene practice?

• A. Accelerate machine startup during maintenance.
• B. Increase production throughput during maintenance.
• C. Document maintenance schedules.
• D. Prevent unexpected energization or startup during service/maintenance to reduce hazard exposure.

Answer: (D)

Lockout/tagout protects workers by preventing unexpected energization or startup of equipment during service or maintenance. By isolating all energy sources and applying a physical lock, a device cannot be turned on again until the lock is removed by the person who applied it, and a clear tag communicates that maintenance is in progress. This ensures stored or residual energy—electrical, mechanical, hydraulic, pneumatic, chemical, or thermal—cannot reach the equipment and surprise workers. Verification that energy is released and zero energy is present is done before any service work begins, and only after the area is safe can maintenance proceed and then the equipment can be reenergized. It’s not about speeding up startup, increasing throughput, or simply documenting schedules; those do not provide the active energy-control needed to reduce hazard exposure.